JP7638490B2 - Soil reaction force detection device and soil reaction force detection method - Google Patents

Description

The present invention relates to a soil reaction force detection device that detects reaction forces received from target soil, and a soil reaction force detection method using the soil reaction force detection device.

Conventionally, there has been a method for measuring the degree of compaction of ground, which involves impacting a freely dropped weight from an appropriate height onto ground after or during compaction, detecting the impact force F and the response speed v of the ground at the time of impact, and using the ratio of the two (F/v) as an index to measure the degree of compaction of the ground (see, for example, Patent Document 1).

There is also a method for measuring soil hardness that uses a spring to create a cone (circular cone) that displaces in response to an axial load, and measures the retraction distance (displacement distance) of the cone in response to the reaction force it receives from the soil when the protruding cone penetrates the soil (see, for example, Patent Document 2).

Patent No. 2523324 Patent No. 6541112

However, when measuring the degree of ground compaction using the method of measuring the degree of ground compaction described in Patent Document 1, the weight can be dropped vertically onto a flat surface by free fall, but it cannot be dropped vertically onto an inclined surface (e.g., a slope). For this reason, the evaluation of the impact force F at the time of collision and the response speed v of the ground differs between flat and inclined surfaces. As a result, it has been difficult to measure the degree of ground compaction on an inclined surface that can be compared with the degree of ground compaction on a flat surface. Furthermore, the method of measuring soil hardness described in Patent Document 2 has the problem that the displacement of the cone is too small when the soil is soft, making it impossible to measure the hardness correctly.

In view of the above circumstances, the present invention aims to provide a soil reaction force detection device and a soil reaction force detection method that can easily grasp the condition of the soil even on an inclined surface, and can grasp the condition of the soil with high accuracy even in soft soil.

The present invention has been made to solve the above-mentioned problems, and the soil reaction force detection device of the present invention comprises a penetration section having an increasing cross-sectional area section in which the cross-sectional area of a cross section perpendicular to the axial direction increases as it moves from the tip side to the base end side in the axial direction, and in which at least the increasing cross-sectional area section is penetrated into the soil, a moving mechanism that moves the penetration section along the axial direction to penetrate the penetration section into the soil, a moving mechanism holding section that holds the moving mechanism, a reaction force detection section that continuously detects the reaction force that the penetration section receives from the soil, and an installation section that is provided on the moving mechanism holding section and defines a ground reference plane perpendicular to the axial direction, and is characterized in that before detection begins, the installation section is abutted against the surface of the target soil, so that the surface of the target soil and the ground reference plane become parallel, and the axial direction of the penetration section takes a detection posture perpendicular to the surface of the target soil, and by moving the penetration section while maintaining the detection posture, the reaction force detection section detects the increasing state of the reaction force that the penetration section receives as the increasing cross-sectional area section passes through the surface of the target soil and enters the target soil.

In addition, in the soil reaction force detection device of the present invention, the tip of the penetration part before detection starts is located at the same position as the ground reference surface of the installation part, or further toward the base end in the axial direction.

In addition, in the soil reaction force detection device of the present invention, the moving mechanism holding section is configured as a cylindrical housing having an opening at the tip side and whose central axis is parallel to the axial direction, and the installation section is configured as an extension section that extends radially outward beyond the inner circumferential surface around the central axis of the housing.

In addition, in the soil reaction force detection device of the present invention, the extension portion is characterized in that it has a ring shape arranged around the central axis of the housing, or a distributed structure in which multiple portions are arranged at intervals around the central axis of the housing.

In addition, in the soil reaction force detection device of the present invention, the movement mechanism stops the movement of the penetration part when the base end in the axial direction of the increased cross-sectional area part is at the same position as the ground reference surface or when the base end in the axial direction is at a position farther away from the target soil than that.

The soil reaction force detection device of the present invention is further characterized by having a detection data storage unit that stores the penetration depth of the penetration part into the target soil in association with the reaction force value detected by the reaction force detection unit at that penetration depth, and a characteristic value calculation unit that calculates the increase amount or increase gradient of the reaction force detected by the reaction force detection unit in an actual measurement section, which is a predetermined section during the movement of the penetration part, and sets the increase amount or increase gradient as a characteristic value of the target soil.

The soil reaction force detection device of the present invention is further characterized by having a detection data storage unit that stores the penetration depth of the penetration part into the target soil in association with the reaction force value detected by the reaction force detection unit at that penetration depth, and a characteristic value calculation unit that calculates the integral value of the reaction force detected by the reaction force detection unit in a measured section, which is a predetermined section during the movement of the penetration part, and sets the integral value as a characteristic value of the target soil.

The soil reaction force detection device of the present invention is further characterized by comprising a detection data storage unit that stores the penetration depth of the penetration part into the target soil in association with the reaction force value detected by the reaction force detection unit at that penetration depth, and a characteristic value calculation unit that calculates the reaction force detected by the reaction force detection unit at a predetermined penetration depth of the penetration part and sets the reaction force as a characteristic value of the target soil.

The soil reaction force detection device of the present invention is further characterized by having a detection data storage unit that stores the penetration depth of the penetration part into the target soil in association with the reaction force value detected by the reaction force detection unit at that penetration depth, and a characteristic value calculation unit that calculates the penetration depth when the reaction force detected by the reaction force detection unit reaches a predetermined value and sets the calculated penetration depth as a characteristic value of the target soil.

The soil reaction force detection device of the present invention further includes a conversion rule storage unit that stores a conversion table or a conversion formula that associates the characteristic values with the evaluation values of the soil, and the characteristic value calculation unit further calculates the evaluation value of the target soil from the characteristic values by referring to the conversion table or the conversion formula.

In addition, in the soil reaction force detection device of the present invention, the specified actual measurement section is characterized in that the initial section from when the penetration part starts to enter the target soil to when it is midway through its movement is excluded.

The soil reaction force detection device of the present invention further includes a movement mechanism control unit that controls the movement mechanism, and the movement mechanism control unit stops the movement of the penetration part by the movement mechanism when the reaction force detection unit detects a reaction force equal to or greater than a predetermined threshold value.

The soil reaction force detection device of the present invention is further characterized by having an angle detection unit that detects the angle of the axial direction relative to the surface of the target soil, and an alarm unit that notifies the outside if the angle detected by the angle detection unit is not within a predetermined range including a preset 90 degrees.

The soil reaction force detection device of the present invention is further characterized by including an angle detection unit that detects the angle of the axial direction relative to the surface of the target soil, and a movement mechanism control unit that stops the movement mechanism if the angle detected by the angle detection unit is not within a predetermined range including a preset 90 degrees.

The soil reaction force detection device of the present invention is further characterized by having an angle detection unit that detects the angle of the axial direction relative to the vertical direction, an operation unit that accepts an operation to set any of the angles detected by the angle detection unit as a reference angle, and an alarm unit that notifies an external device when the angle detected by the angle detection unit is not within a predetermined range including the reference angle.

The soil reaction force detection device of the present invention is further characterized by having an angle detection unit that detects the angle of the axial direction relative to the vertical direction, an operation unit that accepts an operation to set any of the angles detected by the angle detection unit as a reference angle, and a movement mechanism control unit that stops the movement mechanism when the angle detected by the angle detection unit is not within a predetermined range including the reference angle.

The soil reaction detection method of the present invention is a soil reaction detection method using a soil reaction detection device that includes a penetration section having a cross-sectional area increasing section whose cross-sectional area perpendicular to the axial direction increases as it moves from the tip side to the base end side in the axial direction and in which at least the cross-sectional area increasing section penetrates into the soil, a reaction force detection section that detects the reaction force that the penetration section receives from the soil, and an installation section that defines a ground reference plane perpendicular to the axial direction, and is characterized in that before detection begins, the installation section is abutted against the surface of the target soil so that the surface of the target soil and the ground reference plane become parallel, and the axial direction of the penetration section takes a detection posture perpendicular to the surface of the target soil, and while maintaining the detection posture, the cross-sectional area increasing section is passed through the surface of the target soil and penetrates into the target soil, and the reaction force detection section detects the increasing state of the reaction force received by the penetration section.

The soil reaction force detection method of the present invention is also characterized in that the increase or increase gradient of the reaction force detected by the reaction force detection unit is calculated in a measured section, which is a predetermined section during the movement of the penetration part, and is used as a characteristic value of the target soil.

The soil reaction force detection method of the present invention is also characterized in that the integral value of the reaction force detected by the reaction force detection unit is calculated in a measured section, which is a predetermined section during the movement of the penetration part, and is used as the characteristic value of the target soil.

In addition, in the soil reaction force detection method of the present invention, the reaction force detected by the reaction force detection unit at a predetermined penetration depth reached by the movement of the penetration part is calculated and used as the characteristic value of the target soil.

In addition, in the soil reaction force detection method of the present invention, the penetration depth when the reaction force detected by the reaction force detection unit reaches a predetermined value is calculated and used as the characteristic value of the target soil.

The soil reaction force detection device and soil reaction force detection method of the present invention can provide the excellent effect of making it easy to grasp the state of the soil under various conditions.

1 is an oblique view of a soil reaction force detection device in an embodiment of the present invention. This is a cross-sectional view cut axially through the main body device of a soil reaction force detection device in an embodiment of the present invention. 1A is a cross-sectional view taken along the axial direction of a soil reaction force detection device according to an embodiment of the present invention installed on a flat surface, and FIG. 1B is a cross-sectional view taken along the axial direction of a soil reaction force detection device according to an embodiment of the present invention installed on an inclined surface (slope). (A) is a cross-sectional view taken in the axial direction of a soil reaction force detection device in an embodiment of the present invention in which the penetration portion is located at the initial position K. (B) is a cross-sectional view taken in the axial direction of a modified example of a soil reaction force detection device in an embodiment of the present invention in which the penetration portion is located at the initial position K. (A) is a cross-sectional view taken in the axial direction of a soil reaction force detection device in an embodiment of the present invention in which the penetration portion is located at an initial position K different from that in Figure 4 (A). (B) is a cross-sectional view taken in the axial direction of a soil reaction force detection device in an embodiment of the present invention in which the penetration portion is located at the actual measurement start position J. (C) and (D) are graphs showing the movement state of the penetration portion. (A) is a cross-sectional view taken in the axial direction of a soil reaction force detection device in an embodiment of the present invention in which the penetration portion is located at an end position S. (B) is a cross-sectional view taken in the axial direction of a modified example of a soil reaction force detection device in an embodiment of the present invention in which the penetration portion is located at an end position S different from (A). 13A and 13B are bottom views of a soil reaction force detection device showing modified examples of the installation portion in an embodiment of the soil reaction force detection device of the present invention. A diagram showing the hardware configuration of a control device of a soil reaction force detection device in an embodiment of the present invention. A functional block diagram of a control device for a soil reaction force detection device in an embodiment of the present invention. 1A is a diagram showing an example of a conversion table of a soil reaction force detection device according to an embodiment of the present invention, and FIG. 1B is a graph showing the relationship between the penetration depth of a penetration part of a soil reaction force detection device according to an embodiment of the present invention and the reaction force detected at a position corresponding to the penetration depth of the penetration part. 1A and 1B are diagrams showing in chronological order the formation of the initial position K of the penetration portion of the soil reaction force detection device in an embodiment of the present invention. FIG. 1C is a diagram showing the relationship between the amount of movement of the penetration portion of the soil reaction force detection device in an embodiment of the present invention and the reaction force that the penetration portion receives from a hard flat plate at a position corresponding to the amount of movement of the penetration portion. 1A to 1C are cross-sectional views showing in chronological order the operation of a soil reaction force detection device in an embodiment of the present invention. A cross-sectional view of a soil reaction force detection device in an embodiment of the present invention when a load detection unit and a distance detection unit are added. 1A is a plan view showing an example of a selection of a plurality of detection locations of the soil when evaluating the condition of the soil using a soil reaction force detection device according to an embodiment of the present invention, and FIG. 1B is a table showing the property values or evaluation values of the soil calculated based on the reaction forces detected at each of the plurality of detection locations of the soil. 1 is a plan view showing detection points D11, D12, and D13 in a first soil sample D1. FIG. Graphs (A) and (B) show the relationship between the reaction force and the penetration depth of the penetration part when the reaction force of the soil is detected using the soil reaction detection device of this embodiment at three different detection points of the first soil sample D1, the second soil sample D2, and the third soil sample D3. (A) and (B) show different penetration speeds of the penetration part. 1A to 1C are diagrams showing a time series of soil hardness measurements using a soil hardness meter, and 1D is a plan view of a cylindrical container containing the soil to be measured. (A) is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected using the soil reaction detection device of this embodiment for a first soil sample different from that shown in Figure 16, and the number in parentheses at the end of each reaction force detection result represents the index hardness of the soil for the corresponding time. (B) is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected using the soil reaction detection device of this embodiment for a second soil sample different from that shown in Figure 16, and the number in parentheses at the end of each reaction force detection result represents the index hardness of the soil for the corresponding time. 16 is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected using the soil reaction detection device of this embodiment for a third soil sample different from that of FIG. 16, and the number in parentheses at the end of each reaction force detection result represents the index hardness of the soil for the corresponding detection. (B) is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected using the soil reaction detection device of this embodiment for a fourth soil sample, and the number in parentheses at the end of each reaction force detection result represents the index hardness of the soil for the corresponding detection. 1 is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected using the soil reaction detection device of this embodiment for the fifth soil sample, and the number in parentheses at the end of each reaction force detection result represents the index hardness of the soil for the corresponding time. (B) is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected using the soil reaction detection device of this embodiment for the sixth soil sample, and the number in parentheses at the end of each reaction force detection result represents the index hardness of the soil for the corresponding time. 20(A) is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected by the soil reaction detection device of this embodiment for the sixth soil sample, following that of FIG. 20(B), and the numbers in parentheses at the end of each reaction force detection result indicate the index hardness of the soil for the corresponding time. (B) is a graph showing the relationship between the reaction force and the penetration depth of the penetration part when the reaction force received from the soil is detected by the soil reaction detection device of this embodiment for the seventh soil sample, and the numbers in parentheses at the end of each reaction force detection result indicate the index hardness of the soil for the corresponding time. Graph (A) shows the relationship between the amount of movement (penetration depth) of the penetration portion of the soil reaction detection device when the penetration portion of the soil reaction detection device receives a predetermined reaction force against the first to seventh soil samples and the index hardness of the corresponding first to seventh soil samples. Graph (B) shows the relationship between the amount of movement (penetration depth) of the penetration portion of the soil reaction detection device when the penetration portion of the soil reaction detection device receives a predetermined reaction force against the first to seventh soil samples and the indentation resistance of the corresponding first to seventh soil samples.

The following describes an embodiment of the present invention with reference to the attached drawings. Figures 1 to 15 show an example of an embodiment of the invention, in which parts with the same reference numerals as in Figure 1 represent the same items, and the basic configuration is the same as that shown in Figure 1.

<Overall composition>
The soil reaction force detection device 1 according to the embodiment of the present invention detects a reaction force from the soil and evaluates the condition of the soil. For example, when compacting the slope of a river, the soil reaction force detection device 1 is used to evaluate the degree of compaction of the soil corresponding to the slope.

In this embodiment, the soil reaction force detection device 1 includes a main unit 1A and a control device 1B that controls the main unit 1A, as shown in FIG. 1. The control device 1B is separate from the main unit 1A and is communicatively connected to the main unit 1A via a communication line 1C. Note that the soil reaction force detection device 1 may not be differentiated into the main unit 1A and the control device 1B, and the two may be integrated.

<Main unit>
First, the main body device 1A will be described. As shown in Fig. 1 and Fig. 2, the main body device 1A includes a penetration unit 2, a moving mechanism 3, a position detection unit 4, a reaction force detection unit 5, a moving mechanism holding unit 6, an installation unit 7, an angle detection unit 8, and a gripping unit 9.

<Penetration section>
The penetrating part 2 is to be penetrated into the target soil. In this embodiment, the penetrating part 2 has a cone-shaped cone part 20 at its tip and a base part 21, as shown in Figs.

The cone section 20 may be replaced with a shape other than a cone, as long as the area of the cross section perpendicular to the axial direction A increases from the tip end 23 side of the penetrating section 2 to the base end 24 side in the axial direction A along the central axis 22 of the penetrating section 2 as shown in FIG. 2 (hereinafter referred to as the cross-sectional area increasing section). As a shape other than a cone, it may be a pyramid section other than a cone (e.g., triangular pyramid, square pyramid, etc.), or a partial pyramid section composed of a section (partial pyramid) of a pyramid shape excluding the tip in the height direction. This cross-sectional area increasing section may be formed in a part of the axial direction of the penetrating section 2, and its location does not matter.

It is also preferable that the cone section 20 (cross-sectional area increase section) reaches the tip of the penetration section 2, and further, the tip is preferably sharp rather than flat. If the tip of the cross-sectional area increase section is flat, the cross-sectional area increase section will receive a certain amount of reaction force from the beginning of the penetration, so by making the tip sharp, the reaction force received by the cross-sectional area increase section at the beginning of the penetration can be reduced. This allows the cross-sectional area increase section to penetrate smoothly. On the other hand, the tip of the penetration section 2 may be flat. In addition, a part of the axial region from the tip of the penetration section 2 may be composed of a member with a constant cross-sectional area (for example, a cylindrical columnar section), i.e., a cross-sectional area fixing section, rather than the cross-sectional area increase section. In this case, the cross-sectional area increase section will be connected to the rear side of the cross-sectional area fixing section. In the following, the penetration section 2 will be described as having the cone section 20, but the following description is also applicable even if the cone section 20 is replaced with a cross-sectional area increase section other than the cone section 20.

The base 21 is a portion that is continuous with the conical portion 20 at the base end of the conical portion 20. The base 21 may be formed integrally with the conical portion 20, or may be separably connected to the conical portion 20. The base 21 is connected to the moving mechanism 3 so as to be movable together with the moving mechanism 3.

<Moving mechanism>
The moving mechanism 3 moves the penetrating portion 2 along the axial direction A of the penetrating portion 2 to penetrate the penetrating portion 2 into the soil. As described later, the moving mechanism 3 moves (advances) the penetrating portion 2 at least from the initial position K to the end position S under the control of the moving mechanism control unit 10. The initial position K and the end position S will be described later with reference to FIGS. 4 to 6. In this embodiment, the moving mechanism 3 has a rotation source 30, a ball screw mechanism 31, and a penetration side holding unit 32, as shown in FIG. 2.

The rotation source 30 is, for example, a stepping motor, and is controlled and operated by the control device 1B (movement mechanism control unit 10). As shown in FIG. 2, the ball screw mechanism 31 has a shaft portion 310, a shaft support portion 311, and a nut portion 312.

The shaft portion 310 is connected to the rotation source 30 via the coupling portion 33. As a result, the rotation force of the rotation source 30 is transmitted to the shaft portion 310 through the coupling portion 33. The shaft support portion 311 has a bearing and rotatably supports the shaft portion 310 in such a position that the central axis of the shaft portion 310 extends along the axial direction A. The shaft portion 310 has a helical groove (not shown) on the outer circumferential surface around the central axis of the shaft portion 310. The nut portion 312 is screwed to the shaft portion 310 via a ball (not shown) housed in the helical groove. When the rotation source 30 rotates, the shaft portion 310 rotates and the ball (not shown) moves along the helical groove. As a result, the nut portion 312 moves relative to the shaft portion 310 along the axial direction A.

The penetration side holding part 32, together with the nut part 312, moves relative to the shaft part 310 along the axial direction A while holding the penetration part 2. As a result, when the rotation source 30 rotates, the penetration side holding part 32 moves along the axial direction A together with the penetration part 2 through the operation of the ball screw mechanism 31.

As shown in FIG. 1, the penetration side holding part 32 has a guide groove 320 extending in the axial direction A on its outer circumferential surface facing the inner circumferential surface of the moving mechanism holding part 6 (housing 60) described later. And, as shown in FIG. 1, the moving mechanism holding part 6 (housing 60) has an engagement part 64 on its inner circumferential surface that is convex toward the guide groove 320 and engages with the guide groove 320. The penetration side holding part 32 moves while the guide groove 320 and the engagement part 64 are engaged, so that movement in the axial direction A is guaranteed and rotation around the central axis 61 of the moving mechanism holding part 6 (housing 60) is also restricted.

The moving mechanism 3 is not limited to the above configuration, and may be configured with a normal screw mechanism other than a ball screw, a pressure source (e.g., a hydraulic pump, etc.), and a linear motion mechanism having a piston and a cylinder.

<Position detection unit>
The position detector 4 detects, for example, the position of the penetration portion 2. In this embodiment, the position detector 4 is configured by, for example, a linear encoder. As shown in FIG. 1 , the linear encoder includes a scale 40 and a slider 41.

The scale 40 has a scale portion (not shown) that provides position information. The scale 40 is mounted on the moving mechanism holding unit 6 in such a position that the scale portions are aligned along the axial direction A.

The slider 41 is provided on the outer peripheral surface of the penetration side holding portion 32, and moves along the axial direction A together with the penetration side holding portion 32. That is, the slider 41 moves relative to the scale 40. The scale 40 detects the position of the slider 41 and outputs the position information to the movement mechanism control portion 10. The slider 41 may also be configured to have a reading portion (reading sensor) that reads the scale portion as position information on the scale 40, and to output the information of the scale portion read by the reading portion to the movement mechanism control portion 10. The movement mechanism control portion 10 determines the position of the penetration portion 2 based on the output information of the scale portion, and controls the operation of the movement mechanism 3.

<Reaction force detection unit>
The reaction force detection unit 5 detects a reaction force received from the soil when the penetration portion 2 penetrates the target soil. In this embodiment, the reaction force detection unit 5 is configured with a load cell. The load cell is sandwiched between the base end side of the penetration portion 2 and the tip end side of the penetration side holding portion 32. As a result, when the penetration portion 2 receives a reaction force from the soil, the load cell receives a compressive force between the penetration portion 2 and the penetration side holding portion 32 and detects the compressive force as a reaction force received by the penetration portion 2 from the soil.

<Movement mechanism holding unit>
The moving mechanism holding unit 6 holds the moving mechanism 3. In this embodiment, the moving mechanism holding unit 6 is configured as a cylindrical housing 60 with one bottom side open and the other bottom side closed, as shown in FIG. 1. The moving mechanism 3 is housed in the housing 60 in such a position that the central axis 313 of the shaft portion 310 is coaxial with the central axis 61 of the housing 60. The penetration portion 2 is housed in the housing 60 in such a position that the central axis 22 of the penetration portion 2 is coaxial with the central axis 61 of the housing 60, the cone portion 20 faces the opening 63 side, and the base portion 21 faces the penetration side holding portion 32.

Of the moving mechanism 3, the rotation source 30 and the shaft support part 311 are fixed to the housing 60 inside the housing 60. The nut part 312 is screwed onto the shaft part 310 inside the housing 60 so as to be movable in the axial direction A.

The penetration portion 2 is also held by the penetration side holding portion 32 inside the housing 60 so as to be movable in the axial direction A. As a result, the penetration portion 2 enters and exits the housing 60 through the opening 63 of the housing 60.

<Installation section>
When the installation unit 7 is installed on the target soil surface 900, it causes the soil reaction force detection device 1 (penetration unit 2) to assume an attitude in which the axial direction A is perpendicular to the target soil surface 900. When the axial direction A is perpendicular to the target soil surface, the central axis 22 of the penetration unit 2, the central axis 313 of the shaft unit 310, and the central axis 61 of the housing 60 are also perpendicular to the soil surface.

The installation section 7 has a ground plane 70 at its end on the side (tip side) where the penetration section 2 advances in the axial direction A. For convenience, in the soil reaction force detection device 1, the side where the penetration section 2 is provided with respect to the axial direction A is referred to as the tip side, and the opposite side is appropriately referred to as the base side. The ground plane 70 is perpendicular to the axial direction A and defines the ground reference plane Z. This ground reference plane Z is a reference plane that determines the relative position (relative distance) and/or relative angle between the soil reaction force detection device 1 and the soil surface. Before detection begins, when the installation section 7 is installed so that the ground plane 70 abuts the target soil surface 900 in a parallel detection posture, the ground reference plane Z and the soil surface 900 become parallel, and the axial relative position (distance) between the ground reference plane Z and the soil surface 900 is finally determined (detection posture). Measurement is performed while maintaining this detection posture, that is, while maintaining the relative position and relative angle between the ground reference plane Z and the soil surface 900 unchanged.

Depending on the environment, it may be difficult to install the soil reaction force detection device 1 so that the axial direction A is perpendicular to the soil surface. In particular, as shown in FIG. 3(B), when the soil reaction force detection device 1 is installed on an inclined surface, if the operator installs the device so that the axial direction A is perpendicular to the inclined surface, an error may occur. As shown in FIG. 3(A), when the soil surface is horizontal, it is relatively easy to install the soil reaction force detection device 1 so that the axial direction A is perpendicular to the inclined surface, but an error may still occur. As shown in FIG. 3(A) and (B), by using the installation part 7 that defines the ground reference plane Z, the installation part 7 can be pressed against the soil surface 900 to install the soil reaction force detection device 1 so that the axial direction A is perpendicular to the soil surface 900, both on the inclined surface and on the horizontal plane. From the viewpoint of stability during measurement, it is preferable to increase the area of the ground plane 70 of the installation part 7, and for example, this area is preferably 15 cm ² or more, and more preferably 25 cm ² or more.

In addition, assuming that the penetration portion 2 is located at the initial position K, the ground plane 70 (ground reference plane Z) is located at the same position in the axial direction A as the tip portion 23 of the penetration portion 2, or is located on the side (tip side) where the penetration portion 2 advances in the axial direction A. The initial position K refers to the starting position of the penetration portion 2, which serves as a reference before the penetration portion 2 starts to advance.

In addition, in this embodiment, the ground plane 70 (ground reference plane Z) is flush with the tip surface 62 of the moving mechanism holding unit 6 (housing 60) as shown in FIG. 4(A). In this case, the tip surface 62 of the moving mechanism holding unit 6 (housing 60) may be considered to also serve as the ground plane 70 (ground reference plane Z). Furthermore, the ground plane 70 may be located on the side where the penetration portion 2 advances in the axial direction A (the tip side) relative to the tip surface 62 of the moving mechanism holding unit 6 (housing 60), as shown in FIG. 4(B).

Therefore, when the installation unit 7 is installed on the target soil surface 900 so that the ground plane 70 is parallel to the target soil surface 900, the ground reference plane Z and the soil surface 900 become parallel before the penetration unit 2 penetrates the target soil, so that the axial direction A is perpendicular to the target soil surface 900. While maintaining this detection posture, the movement mechanism 3 advances the penetration unit 2 in a state recessed from the tip surface in the axial direction A of the main unit 1A (for example, the tip surface 62 of the movement mechanism holding unit 6 (housing 60) or the ground plane 70 of the installation unit 7: the same applies below), so that the penetration unit 2 protrudes from the tip surface and penetrates into the target soil.

The installation section 7 is provided near the tip of the moving mechanism holding section 6 (housing 60). In this embodiment, the installation section 7 is configured with an extension section 71 that extends outward in the radial direction R from the inner or outer circumferential surface of the housing 60 around the central axis of the housing 60, as shown in FIG. 1. In this embodiment, the radial direction R is a direction perpendicular to the axial direction A. The extension section 71 may be formed integrally with the moving mechanism holding section 6 (housing 60), or may be provided separably as a separate member.

In this embodiment, the extension section 71 is formed in an annular shape. In FIG. 1, the extension section 71 is composed of a ring-shaped (annular) plate material that continuously circles around the central axis of the housing 60. When the ground plane 70 on the soil side is pressed against the soil surface 900, the relative position and relative angle between the soil surface 900 and the ground reference plane Z are determined. On the other hand, the extension section 71 is not limited to a plate structure, but may be a rod-shaped ring material, and this ring material can also define the ground reference plane Z that is parallel to the soil surface 900. Furthermore, the extension section 71 of the present invention is not limited to a ring shape, and may be configured as a distributed structure in which a plurality of extension pieces 72 are arranged at intervals around the central axis of the housing 60, as shown in FIG. 7(A) and (B). Each extension piece 72 is provided with a ground plane piece 73 that abuts against the soil surface. The extension pieces 72 are preferably three in number (three legs), but may be two in number (two legs), or may be four or more in number (four or more legs). The ground reference plane Z is defined by a virtual single plane formed by connecting the multiple ground plane pieces 73. The total area of the multiple ground plane pieces 73 is preferably 15 ^cm2 or more, and more preferably 25 ^cm2 or more.

<Angle detection unit>
The angle detection unit 8 detects the angle of the axial direction A with respect to the vertical direction (gravity direction). The angle detection unit 8 is configured with, for example, a two-axis tilt sensor. In this embodiment, the angle detection unit 8 is provided inside the housing 60, closer to the base end side in the axial direction A than the rotation source 30.

In this embodiment, when the soil reaction force detection device 1 is installed on an inclined surface using the installation unit 7 so that the axial direction A is perpendicular to the inclined surface, the angle of the axial direction A relative to the vertical direction is detected by the angle detection unit 8, and this angle is set as the reference angle. The operator can fine-tune the attitude of the soil reaction force detection device 1 through the gripping unit 9 while checking the angle detected by the angle detection unit 8 while the penetration portion 2 is penetrating the soil.

The angle detection unit 8 may also be configured to detect the angle of the axial direction A relative to the surface of the target soil. In this case, even if the surface of the target soil is an inclined surface (slope), the angle of the axial direction A based on the inclined surface (slope) can be detected. Even if it is difficult to install the soil reaction detection device 1 on an inclined surface so that the axial direction A is perpendicular to the inclined surface using the installation unit 7, the detection results can be used to fine-tune the attitude of the soil reaction detection device 1 if there is an angle detection unit 8 configured as described above. In other words, by roughly determining the attitude of the soil reaction detection device 1 using the installation unit 7 and then fine-tuning it based on the detection results of the angle detection unit 8, the attitude of the soil reaction detection device 1 can be determined so that the axial direction A is accurately perpendicular to the surface of the target soil.

<Grip part>
The gripping portion 9 is a portion that is held by an operator. As shown in FIG. 1, the gripping portion 9 has a receiving surface 90 that receives the pressing force (body weight) applied by the user's hand to the ground. In this embodiment, the gripping portion 9 is composed of two rods extending in the radial direction R from the moving mechanism holding portion 6 (housing 60). Each of the two rods has a receiving surface 90. It is preferable that the receiving surface 90 is parallel to the ground reference surface Z (ground plane 70) and faces upward (toward the rear end of the main body device 1A). The operator holds the two rods with both hands and applies his or her body weight to the receiving surface 90, thereby continuing to press the soil reaction force detection device 1 against the soil surface during measurement. The pressing force acting on the receiving surface 90 suppresses changes in the relative position between the soil reaction force detection device 1 and the soil during measurement. Specifically, the fluctuation in the relative distance and/or relative angle between the ground reference surface Z and the soil surface 900 is suppressed. The location where the receiving surface 90 is provided is not limited to the grip portion 9 , but may be, for example, the rear end portion of the moving mechanism 3 or the moving mechanism holding portion 6 .

<Control device hardware configuration>
Next, the hardware configuration of the control device 1B will be described with reference to Fig. 8. As shown in Fig. 8, the control device 1B is configured by a computer 100 having, for example, a CPU 101, a RAM 102, a ROM 103, a storage medium 104, a wireless communication interface 105, an antenna 106, a wired communication interface 107, a connector group 108, an operation input interface 109, an operation input device 110, a display control unit 111, a display device 112, an audio control unit 113, a speaker 114, a power supply device 115, and a bus 116. Note that the notation I/F in Fig. 8 is an abbreviation for interface.

The CPU 101 is responsible for all processing within the computer 100, and uses the RAM 102 as a working area. For example, a program for starting up the computer 100, an operating system (OS) that realizes the basic operations of the computer 100, and various other programs are written in the ROM 103. The storage medium 104 stores various data, and is composed of, for example, a readable and writable non-volatile memory such as a flash memory, a hard disk drive (HDD), or a solid state drive (SSD).

The wireless communication interface 105 performs conversion processing (modulation and demodulation) of data transmitted and received via wireless communication with an external device (e.g., main unit 1A), and is connected to an antenna 106. The antenna 106 receives data transmitted from the outside and sends it to the wireless communication interface 105. The antenna 106 also transmits data supplied from the wireless communication interface 105 to the outside.

The wired communication interface 107, for example, converts data transmitted and received by wired communication with an external device (for example, the main device 1A), and is connected to the connector group 108. The wired communication interface 107 may be, for example, one that uses a serial bus standard such as USB, but is not limited to this. Other wired communication interfaces 107 may be ones that use a serial bus system such as IEEE1394, or a parallel bus system such as SCSI. The wired communication interface 107 may also include one that can be connected to an external network. One example of a standard for such a wired communication interface 107 is Ethernet (registered trademark). The connector group 108 is made up of multiple connectors and has a shape corresponding to the above communication standards. The wired communication interface 107 includes one that corresponds to each connector in the connector group 108.

The operation input interface 109 transmits operation signals from the operation input device 110 to the CPU 101 via the bus 116. The operation input device 110 may be, for example, a touch panel type in which input is made by touching the display portion of the display device 112, or may be a type in which input is made by pressing a button, or may be constituted by a mouse.

The display control unit 111 causes the display device 112 to display according to the commands of the CPU 101. The commands of the CPU 101 are transmitted to the display control unit 111 via the bus 116. The display device 112 may be a liquid crystal display device embedded in the main body of the computer 100, or an external liquid crystal monitor connected to the main body of the computer 100.

The audio control unit 113 outputs audio through the speaker 114 according to instructions from the CPU 101. Instructions from the CPU 101 are transmitted to the audio control unit 113 through the bus 116.

The power supply unit 115 supplies power to each component in the computer 100. The power supply unit 115 may be configured, for example, as a rechargeable battery, or may be configured as a circuit that converts power supplied from an external power source into a form of power that can be used by the computer 100.

Specifically, the calculator 100 may be configured, for example, as a dedicated computer or as a general-purpose personal computer (desktop computer, laptop computer).

<Function block configuration of the control device>
Next, the control device 1B will be described with reference to Fig. 9. The control device 1B includes a movement mechanism control unit 10, a detection data storage unit 11, a conversion rule storage unit 12, a characteristic value calculation unit 13, a display unit 14, an operation unit 15, a notification unit 16, and a reference position calibration unit 17.

<Movement mechanism control unit>
The moving mechanism control unit 10 controls the operation of the moving mechanism 3. The moving mechanism control unit 10 controls the moving mechanism 3 based on the detection result of the position detection unit 4 mounted on the main body device 1A. At this time, it is preferable to control while referring to the amount of movement from the initial position K, the penetration depth based on the soil surface 900 (ground reference surface Z), and the reaction force output from the reaction force detection unit 5. In this embodiment, the moving mechanism control unit 10 controls the moving mechanism 3 so that the penetration part 2 moves (progresses) from the preset initial position K to the end position S, for example.

Here, the position at which the reaction force that the penetration portion 2 receives from the soil will be output from the reaction force detection unit 5 is defined as the actual measurement start position J. At the actual measurement start position J, as shown in FIG. 5(B), the tip 23 of the penetration portion 2 reaches the target soil surface 900. In other words, the tip 23 of the penetration portion 2 is at the same position as the tip surface in the axial direction A of the main unit 1A (the ground plane 70 or ground reference plane Z in FIG. 5(B)).

In addition, in relation to the actual measurement start position J, at the initial position K, the penetration portion 2 may be located on the opposite side (base end side) of the actual measurement start position J from the side to which the penetration portion 2 advances in the axial direction A, as shown in FIG. 5(A). In this case, at the initial position K, the tip portion 23 of the penetration portion 2 is naturally located on the opposite side (base end side) of the ground plane 70 or ground reference plane Z from the side to which the penetration portion 2 advances in the axial direction A. Also, as shown in FIG. 5(B), the actual measurement start position J and the initial position K may be set at the same position.

The amount of movement (stroke amount) from the actual measurement start position J to the end position S is preferably in the range of 10 (mm) to 200 (mm), more preferably 20 (mm) to 100 (mm), and even more preferably 30 (mm) to 70 (mm). The soil reaction force detection device 1 in this embodiment evaluates the state of the soil surface, that is, the surface layer of the soil in the above range from the actual measurement start position J, and does not evaluate the state of the soil several meters or more underground. In addition, the soil reaction force detection device 1 in this embodiment is intended to simply evaluate the state of the soil. For the above reasons, the above-mentioned range of the amount of movement (stroke amount) is preferable. However, the soil reaction force detection device 1 may be configured to evaluate the state of the soil several meters or more underground, and in that case, the above-mentioned amount of movement (stroke amount) may be accordingly. In addition, basically, it is preferable that the axial length in the axial direction A of the cone portion 20 of the penetration portion 2 is the same as or longer than the above-mentioned amount of movement (stroke amount).

Figures 5(C) and (D) show the relationship between the elapsed time of the movement of the penetration part 2 and the amount of movement. The speed at which the penetration part 2 penetrates is preferably constant as shown in Figure 5(C). This is because a constant speed allows the degree of soil deformation over time to be objectively evaluated. For example, the speed at which the penetration part 2 penetrates is preferably in the range of 0.1 (mm/s) to 10 (mm/s), more preferably 0.5 (mm) to 8 (mm), and even more preferably 1 (mm) to 5 (mm). Note that the penetration speed is preferably as slow as possible because the reaction force at each point during the movement can be detected with high accuracy by the reaction force detection unit 5 described later. On the other hand, it is also preferable to penetrate the penetration part 2 in the depth direction while repeating the reciprocating motion, as shown in Figure 5(D). In this way, the pressure acting on the gravel in the soil during the evacuation timing (return route) is temporarily released, allowing the movement. As a result, it is possible to suppress reaction force measurement errors caused by the tip 23 of the penetrating part 2 continuing to collide with a specific relatively large stone during its progression. In this case, it is sufficient to use the actual measurement data of the section excluding the route that moves overlappingly in the depth direction, as shown by the dotted line.

In this embodiment, as shown in FIG. 6(A), at the end position S, the base end 24 of the cone portion 20 of the penetrating portion 2 and the tip surface (ground plane 70) in the axial direction A of the main body device 1A are at the same position in the axial direction A. In terms of the relationship with the soil, at the end position S in this embodiment, the tip end 23 to the base end 24 of the cone portion 20 of the penetrating portion 2 are in a state of being penetrated into the soil. Note that the end position S is not limited thereto, and may be a position where the cone portion 20 of the penetrating portion 2 is penetrated halfway into the soil, as shown in FIG. 6(B). In this case, the base end 24 of the cone portion 20 of the penetrating portion 2 is located on the opposite side (base end side) to the side where the penetrating portion 2 advances in the axial direction A from the tip surface (ground plane 70 in FIG. 6(B)) in the axial direction A of the main body device 1A. In addition, the position of the penetrating portion 2 at the end position S may be the position of the penetrating portion 2 when a part or all of the base 21 of the penetrating portion 2 is penetrated into the soil. However, in this case, it is preferable to set the range in which the base 21 of the penetration part 2 does not penetrate into the soil as the actual measurement range for the reaction force data.

The movement mechanism control unit 10 is realized mainly by the CPU 101 of the computer 100 executing a program stored in the ROM 103 or the storage medium 104.

<Detection data storage unit>
The detection data storage unit 11 stores the penetration depth of the penetration part 2 into the soil in association with the reaction force value detected by the reaction force detection unit 5 at a position corresponding to the penetration depth. The penetration depth of the penetration part 2 indicates the depth to which the penetration part 2 penetrates from the surface 900 of the soil as a starting point.

(Definition of penetration depth)
In this embodiment, the penetration depth is grasped by the movement amount (stroke amount) of the penetration part 2 based on the actual measurement start position J. The movement mechanism control unit 10 grasps the penetration depth through the movement amount (stroke amount) of the penetration part 2 based on the actual measurement start position J based on the detection result of the position detection unit 4. The actual measurement start position J, which is the starting point of the penetration depth, is defined as the position where the tip 23 of the penetration part 2 coincides with the ground plane 70 or the ground reference plane Z. However, the present invention is not limited to this, and the actual measurement start position J may be defined after the fact by assuming that the initial position where the reaction force value is output from the reaction force detection unit 5 is the position where the tip 23 of the penetration part 2 first contacts the soil.

The detection data storage unit 11 is primarily realized by the storage medium 104 of the computer 100.

<Conversion rule storage unit>
The conversion rule storage unit 12 stores a conversion table in which the characteristic values calculated by the characteristic value calculation unit 13 correspond to the evaluation values of the soil, or a conversion formula for converting the characteristic values into the evaluation values of the soil. Examples of the evaluation values of the soil include those that evaluate the degree of compaction or hardness of the soil. Examples of the evaluation values of the degree of compaction of the soil include the degree of compaction, CBR value, cone index, etc., but these are merely examples and other values may be used. Examples of the evaluation values of the hardness of the soil include soil hardness according to the Yamanaka soil hardness meter method.

As shown in FIG. 10(A), an example of a conversion table is one that is composed of characteristic values An and soil evaluation values Bn that correspond to the characteristic values An. In addition, examples of conversion formulas include a correlation formula between the degree of change in reaction force (characteristic value) and the compaction degree (evaluation value), a correlation formula between the degree of change in reaction force (characteristic value) and the CBR value (evaluation value), and a correlation formula between the degree of change in reaction force (characteristic value) and the cone index (evaluation value).

<Characteristic value calculation section>
The characteristic value calculation unit 13 may calculate the increase in the reaction force detected by the reaction force detection unit 5, the increase gradient (degree of change in the reaction force), the integral value of the reaction force, the penetration depth when the reference reaction force is reached, the reaction force when the reference penetration depth is reached, the maximum reaction force within the actual measurement section, etc., in a predetermined section (hereinafter referred to as the actual measurement section) in the entire section from the actual measurement start position J to the end position S of the penetration part 2, and set them as the characteristic values of the soil. The actual measurement section may be the entire section from the actual measurement start position J to the end position S, or may be a part of the section.

As shown in the graph of the penetration depth of the penetration part 2 into the soil and the reaction force that the penetration part 2 receives from the soil in FIG. 10(B), the entire section can be divided into an initial penetration section, an intermediate penetration section, and a final penetration section based on the penetration depth. Depending on the detection location, there may be stones or holes in the position corresponding to the initial penetration section of the soil. In the initial penetration section at a detection location where there are stones or holes, the reaction force that the penetration part 2 receives may be larger than expected. For this reason, in the initial penetration section, the error in the reaction force that the penetration part 2 receives may be large depending on the detection location. If such an initial penetration section is included in the above-mentioned partial section, the reliability of the characteristic value will be low. For this reason, the initial penetration section may be excluded from the actual measurement section.

As will be described later, if the reaction force received by the penetration section 2 exceeds the tolerance range of the reaction force detection section 5, it may break down. Therefore, the penetration section 2 is configured to be forcibly stopped from moving when the reaction force detected by the reaction force detection section 5 exceeds the upper threshold. In this case, the movement of the penetration section 2 is forcibly stopped at the latter half of the position corresponding to the final penetration section of the soil, and the measurement of the reaction force is interrupted. For this reason, the final penetration section including the planned end position S may include an unmeasurable section. In this case, it is preferable to exclude the entire final penetration section from the actual measurement section, or to exclude only the unmeasurable section, which can increase the reliability of the characteristic value. Therefore, it is also preferable to make the above-mentioned actual measurement section an intermediate penetration section.

The initial penetration section is the section in the initial stage where the penetration section 2 starts to penetrate, starting from the actual measurement start position J. If the total section length is 40 (mm), the initial penetration section is, for example, the section from 0 to 10 (mm) of the total section. The final penetration section is the section in the final stage where the penetration of the penetration section 2 is about to end. If the total section length is 40 (mm), the final penetration section is, for example, the section from 30 to 40 (mm) of the total section. In this case, the intermediate penetration section is the section from 10 to 30 (mm) of the total section.

In the above description, the case where the section is divided based on the penetration depth and the actual measurement section is determined is exemplified, but the present invention is not limited to this. For example, as shown by the dashed line in FIG. 10(B), the entire section can be divided into an initial reaction section, an intermediate reaction section, and a final reaction section based on the reaction force on the vertical axis, and the actual measurement section can be determined from among these. If the maximum measured reaction force is 1200 (dN), the initial reaction penetration section is, for example, the section of 0 to 300 (dN) of the entire section, the final reaction section is, for example, the section of 800 to 1200 (dN), and the intermediate penetration section is the section of 300 to 800 (dN). Hereinafter, the initial penetration section or initial reaction section may be referred to as the "initial section", the intermediate penetration section or intermediate reaction section may be referred to as the "intermediate section", and the final penetration section or final reaction section may be referred to as the "final section".

The actual measurement data consists of two data groups: the amount of movement (penetration depth) of the penetration part 2 from the actual measurement start position J, and the reaction force that the penetration part 2 receives from the soil in conjunction with this. When the characteristic value calculation unit 13 adopts the increase in reaction force as the characteristic value, it can express it by the increase in reaction force in the actual measurement section. When the characteristic value calculation unit 13 adopts the increase gradient of the reaction force (characteristic value) as the characteristic, it can express it by the slope of the function in the actual measurement section, or its equivalent, of a function with the two values of penetration depth and reaction force as variables. Examples of the equivalent of the slope of the function include the slope of a straight line connecting the start and end points in the actual measurement section, and the slope of a straight line or curve when the measurement plot in the actual measurement section is approximated by a straight line or curve.

The characteristic value calculation unit 13 may also calculate the integral value of the reaction force detected by the reaction force detection unit 5 in a specified measured section while the penetration part 2 moves, and use this as the characteristic value of the soil. In this case, the specified measured section is the same as above. In addition, the integral value of the reaction force detected by the reaction force detection unit 5 in the specified measured section is expressed, for example, by the area between the curve representing the relationship between the penetration depth and the reaction force in the intermediate section (intermediate penetration section or intermediate reaction force section) and the horizontal axis representing the penetration depth, as shown in the graph of the penetration depth and the reaction force that the penetration part 2 receives from the soil in Figure 10 (B).

The characteristic value calculation unit 13 may also calculate the reaction force detected by the reaction force detection unit 5 when the penetration part 2 reaches a predetermined penetration depth (criterion penetration depth) and use this as the characteristic value of the soil. The criterion penetration depth can be set to any predetermined penetration depth during the movement of the penetration part 2, for example, to a position of 25 (mm) shown by line segment K1 in Figure 10 (B) within the range excluding the initial section. As a result, the reaction force H1 detected when the depth corresponding to line segment K1 as the criterion penetration depth is reached becomes the characteristic value.

Furthermore, the characteristic value calculation unit 13 may calculate the penetration depth of the penetration part 2 when the reaction force detected by the reaction force detection unit 5 reaches a predetermined value (criterion reaction force) and use this as the characteristic value of the soil. The criterion reaction force can be set arbitrarily, for example, to 400 (dN) shown by the line segment H2 in FIG. 10(B) within a range excluding the initial reaction force section. As a result, the penetration depth K2 when the reaction force value corresponding to the line segment H2 as the criterion reaction force is reached becomes the characteristic value. Note that this criterion reaction force may be the upper limit of the reaction force measured by the reaction force detection unit 5, in which case it becomes the penetration depth of the penetration part 2 at the time of the forced termination of the detection operation. In addition, the characteristic value calculation unit 13 may use the maximum reaction force detected by the reaction force detection unit 5 in the actual measurement section as the characteristic value.

Furthermore, the characteristic value calculation unit 13 may calculate a final characteristic value by combining the various characteristic values described above. For example, the ratio of the reaction force H1 at the reference penetration depth to any one of the reaction force increase amount, increase gradient, or integral value may be used as the final characteristic value.

The characteristic value calculation unit 13 then further refers to the conversion table or the conversion formula to calculate an evaluation value from the characteristic value. This makes it possible to grasp the condition of the target soil.

The characteristic value calculation unit 13 is realized mainly by the CPU 101 of the computer 100 executing a program stored in the ROM 103 or the storage medium 104.

<Display section>
The display unit 14 displays various information, such as the angle detected by the angle detection unit 8, the value of the reaction force detected by the reaction force detection unit 5, the amount of penetration of the penetration unit 2 into the soil, and a preset penetration speed of the penetration unit 2.

The display unit 14 is mainly realized by the display control unit 111 and the display device 112.

<Operation section>
The operation unit 15 accepts various operations. Examples of the various operations include an operation to start the reaction force detection operation, an operation to end the reaction force detection operation, a return operation to return the penetration section 2 to the initial position K, an operation to set the penetration speed of the penetration section 2, an operation to set the penetration amount of the penetration section 2 into the soil, an operation to set the evaluation value, an operation to set the reference angle, and the like. In the operation to set the evaluation value, any one of the above-mentioned is set to be the evaluation value. In the operation to set the reference angle, the angle of the axial direction A relative to the vertical direction may be set as the reference angle in advance, or the angle detected by the angle detection unit 8 when the soil reaction force detection device 1 is installed on an inclined surface using the installation unit 7 so that the axial direction A is perpendicular to the inclined surface may be set as the reference angle.

The operation unit 15 is mainly realized by the operation input interface 109 and the operation input device 110.

<Notification Department>
The notification unit 16 notifies the outside when the angle detected by the angle detection unit 8 is not within a predetermined range including the set reference angle. Examples of the notification mode include notifying the outside with a sound or displaying a warning on the display unit 14. An example of an angle within the predetermined range including the set reference angle is a range of ±5 degrees from the set reference angle. The predetermined range including the set reference angle may be configured to be set by the operation unit 15.

In addition, if the angle detection unit 8 is configured to directly detect the angle of the axial direction A relative to the soil surface, when the angle detected by the angle detection unit 8 is not within a predetermined range including a preset 90 degrees (perpendicular to the soil plane), a notification to that effect can be sent to the outside. For example, the predetermined range including 90 degrees is 85 degrees to 95 degrees. The above-mentioned predetermined range for determining the notification may also be configured to be set by the operation unit 15.

The notification unit 16 is realized mainly by the CPU 101 of the computer 100 executing a program stored in the ROM 103 or the storage medium 104, and outputting the execution result as sound through the audio control unit 113 and the speaker 114, or through the display control unit 111 and the display device 112.

<Reference position calibration unit>
The reference position calibration unit 17 calibrates the actual measurement start position J of the penetration part 2 (which can also be defined as the ground reference plane Z or the ground plane 70) determined by the output of the position detection unit 4. When the actual measurement start position J of the penetration part 2 recognized in advance by the movement mechanism control unit 10 is shifted, it is necessary to calibrate the actual measurement start position J of the penetration part 2. In this embodiment, the actual measurement start position J of the penetration part 2 is assumed to be the same position as the initial position K, and a case will be described in which the initial position K is also calibrated at the same time.

When calibrating the actual measurement start position J, for example, a hard flat plate 170 is prepared. Then, as shown in FIG. 11(A), the tip 23 of the penetration portion 2 is moved to a position recessed from the tip surface in the axial direction A of the main body device 1A (in FIG. 11(A), the ground plane 70). In this state, the soil reaction force detection device 1 is placed so that the ground plane 70 abuts against the hard flat plate 170, and a pressing force is applied to the gripping portion 9 to press the soil reaction force detection device 1 against the hard flat plate 170.

Next, the penetration portion 2 is advanced by the moving mechanism 3. Naturally, as shown in FIG. 11(B), the reaction force detection unit 5 does not detect the reaction force until the tip 23 of the penetration portion 2 comes into contact with the hard flat plate 170. As shown in FIG. 11(C), when the penetration portion 2 moves a distance L and the tip 23 of the penetration portion 2 comes into contact with the hard flat plate 170, the reaction force is detected. When the reaction force is detected, the output value (position data) detected by the position detection unit 4 becomes the actual measurement start position J (position of the ground plane 70, position of the ground reference surface Z) and the initial position K after calibration. The reference position calibration unit 17 stores the position and transmits it to the moving mechanism control unit 10. This allows the moving mechanism control unit 10 to correctly grasp the actual measurement start position J and initial position K of the penetration portion 2.

When the ground reference plane Z, actual measurement start position J, initial position K, etc. of the penetration part 2 are set at a position recessed toward the base end in the axial direction A from the ground plane 70, a hard flat plate having a shape and size that can be inserted into the inside of the movement mechanism holding part 6 (housing 60) can be inserted into the inside of the movement mechanism holding part 6 (housing 60) and the tip of the penetration part 2 can be abutted against the flat plate using the same procedure as above.

<Operation of the soil reaction force detection device>
Next, referring to FIG. 12, a soil reaction detection method using the soil reaction detection device 1 will be described. First, as shown in FIG. 12(A), the operator grasps the gripping portion 9 (not shown) and installs the soil reaction detection device 1 on the target soil surface 900 so that the ground plane 70 of the installation portion 7 is parallel to the target soil surface 900 with the penetration portion 2 located at the initial position K (installation step). As a result, the soil reaction detection device 1 (penetration portion 2) is in a position in which the axial direction A is perpendicular to the target soil surface 900. Note that in FIG. 12(A), at the initial position K, the tip portion 23 of the penetration portion 2 is at the same position in the axial direction A as the tip surface in the axial direction A of the main body device 1A (for example, the tip surface 62 of the moving mechanism holding portion 6 (housing 60), the ground plane 70 of the installation portion 7, and the ground reference surface Z), and is at the same position as the target soil surface 900.

The angle of axial direction A relative to the vertical direction (gravity direction) is then detected by angle detection unit 8, and the angle is displayed on display unit 14 (angle detection step). A corresponding operation is performed on operation unit 15, and the angle displayed on display unit 14 is set as the reference angle. After that, if the angle of axial direction A is not within a predetermined range that includes the reference angle, the notification unit 16 notifies the outside (notification step).

In addition, when the angle detection unit 8 is configured to detect the angle of the axial direction A relative to the target soil surface, the angle of the axial direction A relative to the target soil surface 900 is detected by the angle detection unit 8, and the angle is displayed on the display unit 14 (angle detection step). At this time, if the angle of the axial direction A relative to the target soil surface 900 is not within a predetermined range including 90 degrees (e.g., 85 degrees to 95 degrees), an external notification is issued by the notification unit 16 (notification step). In either of the above cases, the operator adjusts the attitude of the soil reaction force detection device 1 (penetration unit 2) while watching the angle displayed on the display unit 14, and determines the attitude of the soil reaction force detection device 1 (penetration unit 2).

When the operation unit 15 is operated to start the reaction force detection operation while the soil reaction force detection device 1 (penetration unit 2) is maintained in the above-mentioned position, the movement mechanism control unit 10 operates the movement mechanism 3, and the penetration unit 2, which is located at the initial position K, begins to move (penetration unit movement (progression) step). When the operation to start the reaction force detection operation is performed, the position detection unit 4 detects the current position of the penetration unit 2, but if the penetration unit 2 is not located at the initial position K, the movement mechanism control unit 10 moves the penetration unit 2 to the initial position K by the movement mechanism 3 based on the detection result in the position detection unit 4 (position return step).

After the penetration section 2 starts to advance, the operator applies a pressure of, for example, about 5 to 10 (kgf) to the receiving surface 90 of the gripping section 9 so that the reaction force from the soil does not cause the installation section 7 to float off the soil or the posture of the soil reaction detection device 1 (main unit 1A) to collapse. As shown in FIG. 13, a load detection section 18 that detects the load applied between the moving mechanism holding section 6 (housing 60) and the installation section 7 may be added to the soil reaction detection device 1 (main unit 1A). If the installation section 7 floats off the soil or the posture of the soil reaction detection device 1 (main unit 1A) collapses, the load applied between the moving mechanism holding section 6 (housing 60) and the installation section 7 becomes smaller. Therefore, if the load applied between the moving mechanism holding section 6 (housing 60) and the installation section 7 becomes smaller than a predetermined threshold, the display section 14 displays this fact, or the notification section 16 notifies the outside of this fact.

Also, instead of or in addition to the load detection unit 18, a distance detection unit 19 may be provided in the soil reaction detection device 1 (main unit 1A). The distance detection unit 19 is provided in the moving mechanism holding unit 6 (housing 60) or the installation unit 7. If the installation unit 7 floats off the soil or the detection posture of the soil reaction detection device 1 (main unit 1A) collapses, the distance detected by the distance detection unit 19 changes. In other words, this means that the relative position and/or relative angle between the ground reference plane Z and the soil surface 900 has changed. If the distance detected by the distance detection unit 19 exceeds a preset range, the installation unit 7 floats off the soil and the posture of the soil reaction detection device 1 (main unit 1A) collapses significantly, and this is displayed on the display unit 14 or is notified to the outside by the notification unit 16.

Then, when the penetrating portion 2 advances and the tip 23 of the penetrating portion 2 comes into contact with the surface of the soil, the penetrating portion 2 reaches the actual measurement start position J. As shown in FIG. 12(B), the tip 23 of the penetrating portion 2 is sharp, so it can smoothly pass through the actual measurement start position J and penetrate into the soil, and the moving mechanism 3 advances deeper into the soil. During this time, the reaction force that the penetrating portion 2 receives from the soil is detected continuously or discontinuously at regular intervals by the reaction force detection unit 5 (reaction force detection step). In other words, the reaction force while the penetrating portion 2 is passing through the soil surface 900 and entering the soil is detected by the reaction force detection unit 5. As a result, the increasing state of the reaction force that the penetrating portion 2 receives from the soil can be grasped. The detected reaction force is, for example, linked to the penetration depth of the penetrating portion 2 and sequentially stored in the detection data storage unit 11.

In addition, if the soil reaction force detection device 1 (penetration part 2) assumes a position such that the angle of the axial direction A falls outside a predetermined range including the reference angle while the penetration part 2 is moving, or if the soil reaction force detection device 1 (penetration part 2) assumes a position such that the angle of the axial direction A with respect to the target soil surface 900 falls outside a predetermined range including 90 degrees, this is detected by the angle detection part 8 and the notification part 16 notifies the fact (notification step). When a notification is received, it is preferable, in principle, to repeat the detection operation of the reaction force received from the soil.

However, when the notification is given, the moving mechanism control unit 10 may temporarily halt the advancement of the penetration section 2 by the moving mechanism 3. In this case, the worker adjusts the attitude of the soil reaction force detection device 1 (penetration section 2) while watching the angle displayed on the display unit 14 to correct the attitude of the soil reaction force detection device 1 (penetration section 2). Then, when the attitude of the soil reaction force detection device 1 (penetration section 2) is within the specified range, the moving mechanism control unit 10 may again start the advancement of the penetration section 2 by the moving mechanism 3, or may perform a start operation on the operation unit 15 to start the advancement of the penetration section 2 by the moving mechanism 3. In this way, even if the attitude of the soil reaction force detection device 1 (penetration section 2) is lost, the detection operation of the reaction force received from the soil can be continued without having to be restarted.

When the position detection unit 4 detects that the penetration portion 2 has reached the end position S, the movement mechanism control unit 10 stops the movement of the penetration portion 2 by the movement mechanism 3. This ends the penetration portion movement (progression) step. As shown in FIG. 12(C) , at the end position S in this embodiment, the base end 24 of the cone portion 20 in the penetration portion 2 and the ground plane 70 or the tip surface 62 of the movement mechanism holding unit 6 (housing 60) are in the same position in the axial direction A. In other words, the entire cone portion 20 is penetrated into the soil.

Furthermore, even before the penetration portion 2 reaches the end position S, if the reaction force detection unit 5 detects a reaction force exceeding a predetermined upper threshold, the movement mechanism control unit 10 forcibly stops the movement of the penetration portion 2 by the movement mechanism 3. This is to prevent the load cell from breaking down if the reaction force detection unit 5 is composed of a load cell and a large reaction force is applied to the load cell. The same applies to other reaction force detection units 5 that may break down due to the application of a large reaction force. In other words, the concept of the end position S includes the case where the middle of the cone portion 20 in the axial direction A is at the same position as the ground plane 70 or the tip surface 62 of the movement mechanism holding unit 6 (housing 60).

This ends the reaction force detection operation for the target soil. When an operation to end the reaction force detection operation is then performed on the operation unit 15, the movement mechanism control unit 10 operates the movement mechanism 3 to move the penetration unit 2 backward and return it to the initial position K.

Furthermore, when detection of the reaction force for the target soil is completed, the characteristic value calculation unit 13 calculates the characteristic value, and further calculates an evaluation value for evaluating the state of the soil from the characteristic value. For example, the increase in the reaction force detected by the reaction force detection unit 5, the increase gradient (degree of change in the reaction force), the integral value of the reaction force, the penetration depth when the judgment reference reaction force is reached, the reaction force when the judgment reference penetration depth is reached, the maximum reaction force within the actual measurement section, etc. can be calculated and used as the characteristic value of the soil. The method of calculating the evaluation value based on the characteristic value can be set in advance using a conversion table, conversion formula, etc. These characteristic values and evaluation values are then displayed on the display unit 14.

As described above, in this soil reaction detection method, the portion of the penetrating portion 2 that penetrates into the soil is configured, like the cone portion 20, so that the cross-sectional area of the section perpendicular to the axial direction A increases as the penetration progresses. In other words, in this soil reaction detection method, the facing area of the penetrating portion 2 that faces the soil increases as the penetrating portion 2 progresses. Moreover, in principle, in this soil reaction detection method, the cone portion 20 is penetrated into the soil at a constant penetration speed from the tip end 23 to the base end 24, and the reaction force of the penetrating portion 2 received from the soil at this time is detected continuously or discontinuously, and an evaluation value for the soil is calculated using some or all of the reaction force data.

When evaluating the condition of soil using the soil reaction detection device 1 according to the embodiment of the present invention, it is preferable to perform the reaction detection operation multiple times for the target soil 910 by changing the detection location, as shown in FIG. 14(A). In other words, the reaction detection operation is performed at detection locations 911-919 of the target soil 910. Then, the average value of the multiple characteristic values or evaluation values calculated at the detection locations 911-919 shown in FIG. 14(B) is regarded as the regular characteristic value or evaluation value for the soil 910. When calculating the average value of the multiple characteristic values or evaluation values, at least the maximum evaluation value C2 and/or the minimum evaluation value C7 of the multiple characteristic values or evaluation values C1-C9 may be excluded, and the average value may be calculated from the remaining data.

<Verification 1 using a soil reaction force detection device>
The inventors of the present application compacted the prepared soils, preparing a first soil sample D1 which was the most compacted, a second soil sample D2 which was the second most compacted, and a third soil sample D3 which was the least compacted.

Then, for each of the first soil sample D1, the second soil sample D2, and the third soil sample D3, the reaction force received from the soil was detected three times using the soil reaction detection device 1 of this embodiment at different detection locations. For example, for the first soil sample D1, as shown in FIG. 15, the reaction force received from the soil was detected a total of three times using the soil reaction detection device 1 of this embodiment at detection points D11, D12, and D13. The same was true for the second soil sample D2 and the third soil sample D3.

The results are shown in graphs in Fig. 16(A) and (B). The length of the cone portion 20 in the axial direction A is 40 (mm), so the movement amount (stroke amount) of the cone portion 20 is 40 (mm). Also, Fig. 16(A) shows the result when the penetration portion 2 is moved at a penetration speed of 5 (mm/s), and Fig. 16(B) shows the result when the penetration portion 2 is moved at a penetration speed of 1 (mm/s). And, in order to prevent failure of the load cell as the reaction force detection portion 5, the movement of the penetration portion 2 is set to stop when the reaction force exceeds 1000 (dN). Also, in the graphs of Fig. 16(A) and (B), the horizontal axis is the penetration depth of the penetration portion 2 based on the initial position K (stroke amount starting from the actual measurement start position J), and the vertical axis is the reaction force received by the penetration portion 2 at a position corresponding to the penetration depth of the penetration portion 2. In addition, in the graphs of Figures 16(A) and (B), the thin dotted lines represent the results for the first soil sample D1, the thick dotted lines represent the results for the second soil sample D2, and the thick solid lines represent the results for the third soil sample D3.

Although there is more variation in the reaction force in FIG. 16(A), where the penetration speed is fast, compared to FIG. 16(B), where the penetration speed is slow, for example, in the section where the penetration depth of the penetration part 2 (stroke amount starting from the actual measurement start position J) is 20 (mm) to 30 (mm), the slope of the graph (increase amount, or increase gradient) is generally greater for the first soil sample D1, the second soil sample D2, and the third soil sample D3 in that order. Also, since the slope of the graph (increase amount, or increase gradient) is greater, it can be inferred that the integral value will also be greater in the section where the penetration depth of the penetration part 2 (stroke amount starting from the actual measurement start position J) is 20 (mm) to 30 (mm). Therefore, the condition of each soil can be evaluated from the slope of the graph (increase amount, or increase gradient) and the integral value.

The state of each soil may be evaluated based on the reaction force at the penetration depth (e.g., 25 mm, 40 mm, etc.) of the penetration portion 2 in each of the first soil sample D1, the second soil sample D2, and the third soil sample D3. The portion to be taken as the specified penetration depth can be set appropriately.

<Verification 2 using a soil reaction force detection device>
Next, the inventors prepared first to eighth soil samples with different degrees of compaction. The first to seventh soil samples were prepared by crushing bentonite crushed stone or red soil of a certain particle size or less that had been passed through a 2 mm sieve and placing it in a cylindrical container. The first soil sample was not compressed at all in the cylindrical container. The second to seventh soil samples were compressed to different degrees in the cylindrical container. The compression degrees increased in the order of the second to seventh soil samples. The hardness of each of the first to seventh soil samples was measured by the Yamanaka soil hardness meter method using the soil hardness meter 800 shown in Figure 17, while the reaction force of each of the first to seventh soil samples was detected using the soil reaction force detection device 1.

The soil hardness meter 800 has a cone 810 that can be displaced in the axial direction of the case 820 by the coil spring 830 in response to the load received from the soil. The scale 840 moves in accordance with the compression of the coil spring 830. The surface of the scale 840 is marked with the index hardness (mm) and the pressing resistance (kPa). As shown in Figures 17(A) to (C), in the Yamanaka soil hardness meter method using the soil hardness meter 800, the cone 810 at the tip of the soil hardness meter 800 is inserted into the central region M of the soil contained in the cylindrical container (see Figure 17(D)) until the tip 821 of the case 820 comes into contact with the surface 900 of the soil. The graduations of the scale 840 that move in accordance with the compression of the coil spring 830 at this time are read to determine the index hardness (mm) and pressing resistance (kPa) of the soil. In this verification, the soil hardness meter 800 used was a DIK5-5553 push cone manufactured by Daiki Rika Kogyo Co., Ltd. The cone 810 of the soil hardness meter 800 and the cone portion 20 of the soil reaction force detection device 1 were the same size and shape, with both having a length of 40 (mm) in the axial direction A, a base radius of 9 (mm), and an apex angle of 25.20 degrees. The spring strength of the coil spring 830 of the soil hardness meter 800 was 78.4 N/4 (mm) of the soil hardness meter 800. The detection of reaction force using the soil reaction force detection device 1 was performed after the measurement with the soil hardness meter 800 was completed, by filling the central region M of the soil where a hole had been made by the soil hardness meter 800 and compressing it to return it to its original state. The operations by the soil hardness meter 800 and the soil reaction force detection device 1 are collectively referred to as soil measurement operations. In addition, when the soil measurement operation is repeated multiple times, after the detection operation by the soil reaction detection device 1 is completed, the soil reaction detection device 1 will naturally fill in the central region M of the soil where the hole was made and compress it, etc., to return it to its original state.

The first soil sample was a 446 g sample containing crushed bentonite stones of a certain particle size or less that had been crushed and passed through a 2 mm sieve. The first soil sample was filled into a cylindrical container without being compressed. In this verification, the soil measurement operation was repeated twice for the first soil sample. As a result, in the first and second measurements using the soil hardness meter 800, it was confirmed that the soil index hardness (mm) was 0 mm in both cases, and it was confirmed that the first soil sample was soft. Since the first soil sample was soft, as shown in FIG. 18A, in the first and second measurements using the soil reaction force detection device 1, the reaction force was not detected until the penetration depth was quite deep, at 29 mm. After that, the reaction force was detected.

The second soil sample was a 470g sample containing crushed bentonite stones of a certain particle size or less that had been crushed and passed through a 2mm sieve. The second soil sample was then filled into a cylindrical container and slightly compressed. In this verification, the soil measurement operation was repeated five times for the second soil sample. As a result, in the measurement using the soil hardness meter 800, it was confirmed that the index hardness (mm) of the soil was 0mm in the first measurement, 3mm in the second measurement, 5mm in the third measurement, 6mm in the fourth measurement, and 5mm in the fifth measurement, and it was confirmed that the second soil sample was a relatively soft soil. Since the second soil sample was a relatively soft soil, as shown in FIG. 18B, in the detection of the reaction force on the second soil sample using the soil reaction force detection device 1 in each measurement, the reaction force was not detected until the penetration depth was relatively deep between 16 and 22mm. After that, the reaction force was detected.

The third soil sample was a 529g sample containing crushed bentonite stones of a certain particle size or less that had been crushed and passed through a 2mm sieve. A predetermined amount of the third soil sample was placed in a cylindrical container to make a first layer, which was then compressed under the weight of the whole body. A predetermined amount of the third soil sample was placed on top of the first layer to make a second layer, which was then compressed under the weight of the whole body. A predetermined amount of the third soil sample was placed on top of the second layer to make a third layer, which was then compressed under the weight of the whole body. In this verification, the soil measurement operation was repeated five times for the third soil sample. Note that the soil measurement operation was not performed at the same position, but at a different position each time. As a result, it was confirmed that the soil index hardness (mm) was 10mm the first time, 11mm the second time, 11mm the third time, 12mm the fourth time, and 12mm the fifth time in the measurement using the soil hardness meter 800. As shown in FIG. 19(A), when the reaction force was detected for the third soil sample using the soil reaction force detection device 1, the reaction force was not detected until the penetration depth reached a relatively deep point between 10 and 13 mm. After that, the reaction force was detected.

The fourth soil sample was a 567g sample containing slightly larger bentonite crushed stones and bentonite crushed stones that had been sieved through a 0.5mm sieve. The slightly larger bentonite crushed stones were filled into a cylindrical container to a depth of 65mm, and the bentonite crushed stones that had been sieved through a 0.5mm sieve were then placed on top of the bentonite crushed stones and compressed to a depth of 70mm, filling the cylindrical container with the material. In this verification, the soil measurement operation was repeated six times for the fourth soil sample. Note that the soil measurement operation was not performed in the same position, but was performed at a different position each time. As a result, it was confirmed that the soil hardness index (mm) was 9mm in the first measurement, 9mm in the second measurement, 10mm in the third measurement, 9mm in the fourth measurement, 9mm in the fifth measurement, and 11mm in the sixth measurement. As shown in FIG. 19B, when the reaction force was detected for the fourth soil sample using the soil reaction force detection device 1, the reaction force was not detected until the penetration depth reached a relatively deep point between 6 and 11 mm. After that, the reaction force was detected.

The fifth soil sample was a 418g sample containing akadama soil of a certain particle size or less that had been crushed and passed through a 2mm sieve. A predetermined amount of the fifth soil sample was placed in a cylindrical container to make the first layer, and compressed under the weight of the whole body. A predetermined amount of the fifth soil sample was placed on top of the first layer to make the second layer, and compressed under the weight of the whole body. A predetermined amount of the fifth soil sample was placed on top of the second layer to make the third layer, and compressed under the weight of the whole body. Compression was then further added by driving the entire layer from the top of the cylindrical container, and additional akadama soil was placed up to the top of the cylindrical container, and compressed again under the weight of the whole body. In this verification, the soil measurement operation was repeated five times for the fifth soil sample. Note that the soil measurement operation was not performed in the same position, but in a shifted position each time. As a result, measurements using the soil hardness meter 800 confirmed that the index hardness (mm) of the soil was 14 (mm) the first time, 15 (mm) the second time, 16 (mm) the third time, 15 (mm) the fourth time, and 16 (mm) the fifth time. As shown in FIG. 20(A), when the reaction force was detected on the fifth soil sample using the soil reaction force detection device 1 each time, no reaction force was detected until the relatively deep penetration depth of between 9 and 12 (mm). After that, reaction force was detected.

The sixth soil sample was a 550g sample containing crushed bentonite stones of a certain particle size or less that had been crushed and passed through a 0.5mm sieve. The sixth soil sample was then filled into a cylindrical container and compressed. In this verification, the soil measurement operation was repeated 16 times for the sixth soil sample. The soil measurement operation was not performed at the same position, but at a different position each time. As a result, it was confirmed that the soil index hardness (mm) was 27mm for the first to third measurements, 26mm for the fourth to ninth measurements, 17mm for the tenth to twelfth measurements, and 20mm for the thirteenth to sixteenth measurements. As shown in FIG. 20B, in the detection of the reaction force on the sixth soil sample using the soil reaction force detection device 1 for the first to ninth measurements, the reaction force was not detected until the penetration depth was relatively shallow between 6mm and 9mm, but the reaction force was detected thereafter. Also, as shown in FIG. 21(A), when the reaction force was detected on the sixth soil sample using the soil reaction force detection device 1 from the 10th to 16th times, the reaction force was not detected until the penetration depth reached a relatively shallow depth of 4 to 9 mm, but the reaction force was detected from that point on.

The seventh soil sample was made by mixing 500 g of akadama soil of a certain particle size or less that had been crushed and passed through a 2 mm sieve with 150 g of water. A predetermined amount of the seventh soil sample was then placed in a cylindrical container to make the first layer, which was then compressed by driving in, a predetermined amount of the seventh soil sample was placed on top of the first layer to make the second layer, which was then compressed by driving in, and a predetermined amount of the seventh soil sample was placed on top of the second layer to make the third layer, which was then compressed by driving in, for a total of 483 g of sample out of the 650 g sample. In this verification, the soil measurement operation was repeated seven times for the seventh soil sample. As a result, it was confirmed that the soil index hardness (mm) was 30 mm in the first measurement and 31 mm in the second to seventh measurements using the soil hardness meter 800. As shown in FIG. 21(B), when the reaction force for the seventh soil sample was detected using the soil reaction force detection device 1, no reaction force was detected until the penetration depth reached a shallow depth of 0 to 1 mm, but reaction force was detected from that point on.

Based on the above results, the relationship between the index hardness (mm) of the soil and the penetration depth (mm) of the penetration part 2 when a reaction force of 1000 (dN) is detected is shown in Figure 22 (A). Also, the relationship between the soil indentation resistance (10 ³ Pa) and the penetration depth (mm) of the penetration part 2 when a reaction force of 1000 (dN) is detected is shown in Figure 22 (B). Note that when only a reaction force of 1000 (dN) or less is detected, for convenience, it is replaced with the penetration depth (mm) of the penetration part at the maximum reaction force detected.

As shown in FIG. 22(A), the index hardness (mm) of the soil and the penetration depth (mm) of the penetration section 2 when a reaction force of 1000 (dN) is detected can be approximated by a straight line. Similarly, as shown in FIG. 22(B), the penetration resistance (10 ³ Pa) of the soil and the penetration depth (mm) of the penetration section 2 when a reaction force of 1000 (dN) is detected can be approximated by a straight line. In other words, if the reaction force received from the soil is detected by the soil reaction force detection device in this embodiment, the index hardness (mm) and the penetration resistance (10 ³ Pa) of the soil can be obtained based on a predetermined relational expression. In other words, the soil reaction force detection device in this embodiment can be configured to have an aspect as a soil hardness meter by providing a soil hardness calculation unit in the control device 1B that calculates the index hardness (mm) and the penetration resistance (10 ³ Pa) of the soil from the penetration depth (mm) of the penetration section 2 when a predetermined reaction force is detected using a predetermined relational expression. In particular, this soil reaction detection device can detect reaction force fluctuations with high sensitivity even in the surface layer of extremely soft soil, so that the characteristic values calculated from these reaction force fluctuations can be converted into characteristic values such as the degree of compaction, CBR value, and cone index.

The soil reaction force detection device and soil reaction force detection method of the present invention are not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention.

REFERENCE SIGNS LIST 1 Soil reaction force detection device 1A Main unit 1B Control device 1C Communication line 2 Penetration section 3 Moving mechanism 4 Position detection section 5 Reaction force detection section 6 Moving mechanism holding section 7 Installation section 8 Angle detection section 9 Grip section 10 Moving mechanism control section 11 Detection data storage section 12 Conversion rule storage section 13 Characteristic value calculation section 14 Display section 15 Operation section 16 Notification section 17 Reference position calibration section 18 Load detection section 19 Distance detection section 20 Cone section 21 Base section 22 Central axis 23 Tip section 24 Base end section 60 Housing 62 Tip surface 63 Opening 70 Ground plane 71 Extension section 90 Receiving surface 900 Soil surface A Axial direction J Actual measurement start position K Reference position S End position

Claims (20)

A penetration portion having an increasing cross-sectional area portion in which the cross-sectional area of a cross section perpendicular to the axial direction increases as the axial direction proceeds from the tip side to the base end side, and at least the increasing cross-sectional area portion penetrates into the soil;
A moving mechanism that moves the penetration portion along the axial direction to penetrate the penetration portion into the soil;
A moving mechanism holding unit that holds the moving mechanism;
A reaction force detection unit that continuously detects a reaction force that the penetration unit receives from the soil;
a mounting portion provided on the moving mechanism holding portion and defining a ground reference plane perpendicular to the axial direction;
A characteristic value calculation unit that calculates an integral value of the reaction force detected by the reaction force detection unit in a measured section that is a predetermined section during the movement of the penetration unit, and sets the integral value as a characteristic value of the target soil;
Equipped with
Before the start of detection, the installation portion is brought into contact with the surface of the target soil, so that the surface of the target soil and the ground reference plane become parallel to each other, and the axial direction of the penetration portion is perpendicular to the surface of the target soil.
The penetration portion is moved while maintaining the detection posture, and the reaction force detection portion detects an increase in the reaction force received by the penetration portion when the cross-sectional area increasing portion passes through the surface of the target soil and enters the target soil.
Soil reaction force detection device. The tip of the penetration portion before detection is started is located at the same position as the ground reference surface of the installation portion or on the base end side in the axial direction.
A soil reaction force detection device as claimed in claim 1. the moving mechanism holding unit is configured as a cylindrical housing having an opening on a tip side and a central axis parallel to the axial direction,
The installation portion is configured as an extension portion that extends radially outward from an inner circumferential surface around a central axis of the housing.
A soil reaction force detection device as claimed in claim 1 or 2. The extension part is a ring-shaped part arranged around the central axis of the housing, or a distributed structure in which a plurality of extension parts are arranged at intervals around the central axis of the housing.
4. A soil reaction force detection device as claimed in claim 3. The movement mechanism stops the movement of the penetration portion when the base end of the axial direction of the cross-sectional area increasing portion is at the same position as the ground reference surface or when the base end of the axial direction is at a position farther away from the target soil than the ground reference surface.
A soil reaction force detection device according to any one of claims 1 to 4. a detection data storage unit that stores a penetration depth of the penetration unit into the target soil and a reaction force value detected by the reaction force detection unit at the penetration depth in association with each other;
A second characteristic value calculation unit that calculates the increase amount or increase gradient of the reaction force detected by the reaction force detection unit in the actual measurement section, which is a predetermined section during the movement of the penetration part, and sets the increase amount or increase gradient as a characteristic value of the target soil;
The present invention is characterized in that it comprises
A soil reaction force detection device according to any one of claims 1 to 5. A detection data storage unit is provided for storing the penetration depth of the penetration part into the target soil and the reaction force value detected by the reaction force detection unit at the penetration depth in association with each other.
A soil reaction force detection device according to any one of claims 1 to 5. a detection data storage unit that stores a penetration depth of the penetration unit into the target soil and a reaction force value detected by the reaction force detection unit at the penetration depth in association with each other;
A second characteristic value calculation unit that calculates the reaction force detected by the reaction force detection unit at a predetermined penetration depth of the penetration unit and sets the reaction force as a characteristic value of the target soil;
The present invention is characterized in that it comprises
A soil reaction force detection device according to any one of claims 1 to 5. a detection data storage unit that stores a penetration depth of the penetration unit into the target soil and a reaction force value detected by the reaction force detection unit at the penetration depth in association with each other;
A second characteristic value calculation unit that calculates the penetration depth when the reaction force detected by the reaction force detection unit reaches a predetermined value and sets the penetration depth as a characteristic value of the target soil;
The present invention is characterized in that it comprises
A soil reaction force detection device according to any one of claims 1 to 5. a conversion rule storage unit that stores a conversion table or a conversion formula that associates the characteristic values with the soil evaluation values;
The characteristic value calculation unit further refers to the conversion table or the conversion formula to calculate the evaluation value of the target soil from the characteristic value.
A soil reaction force detection device according to any one of claims 6 to 9. The predetermined measured section is characterized in that an initial section from when the penetration section starts entering the target soil to when the penetration section moves is excluded.
A soil reaction force detection device according to any one of claims 6 to 10. A movement mechanism control unit that controls the movement mechanism,
The movement mechanism control unit is characterized in that, when the reaction force detection unit detects a reaction force equal to or greater than a predetermined threshold, the movement mechanism stops the movement of the penetration portion.
A soil reaction force detection device according to any one of claims 1 to 11. an angle detection unit for detecting an angle of the axial direction with respect to a surface of the target soil;
a notification unit that notifies an outside device of the angle detected by the angle detection unit when the angle is not within a predetermined range including 90 degrees that is set in advance;
The present invention is characterized in that it comprises
A soil reaction force detection device according to any one of claims 1 to 12. A penetration portion having an increasing cross-sectional area portion in which the cross-sectional area of a cross section perpendicular to the axial direction increases as the axial direction proceeds from the tip side to the base end side, and at least the increasing cross-sectional area portion penetrates into the soil;
A moving mechanism that moves the penetration portion along the axial direction to penetrate the penetration portion into the soil;
A moving mechanism holding unit that holds the moving mechanism;
A reaction force detection unit that continuously detects a reaction force that the penetration unit receives from the soil;
a mounting portion provided on the moving mechanism holding portion and defining a ground reference plane perpendicular to the axial direction;
an angle detection unit for detecting an angle of the axial direction with respect to a surface of the target soil;
a movement mechanism control unit that stops the movement mechanism when the angle detected by the angle detection unit is not within a predetermined range including a preset 90 degree;
Equipped with
Before the start of detection, the installation portion is brought into contact with the surface of the target soil, so that the surface of the target soil and the ground reference plane become parallel to each other, and the axial direction of the penetration portion is perpendicular to the surface of the target soil.
The penetration portion is moved while maintaining the detection posture, and the reaction force detection portion detects an increase in the reaction force received by the penetration portion when the cross-sectional area increasing portion passes through the surface of the target soil and enters the target soil.
Soil reaction force detection device. A penetration portion having an increasing cross-sectional area portion in which the cross-sectional area of a cross section perpendicular to the axial direction increases as the axial direction proceeds from the tip side to the base end side, and at least the increasing cross-sectional area portion penetrates into the soil;
A moving mechanism that moves the penetration portion along the axial direction to penetrate the penetration portion into the soil;
A moving mechanism holding unit that holds the moving mechanism;
A reaction force detection unit that continuously detects a reaction force that the penetration unit receives from the soil;
a mounting portion provided on the moving mechanism holding portion and defining a ground reference plane perpendicular to the axial direction;
an angle detection unit that detects an angle of the axial direction with respect to a vertical direction;
an operation unit that accepts an operation to set any one of the angles detected by the angle detection unit as a reference angle;
a notification unit that notifies an outside device of the angle detected by the angle detection unit when the angle is not within a predetermined range including the reference angle;
Equipped with
Before detection begins, the installation portion is brought into contact with the surface of the target soil, so that the surface of the target soil and the ground reference plane are parallel to each other, and the axial direction of the penetration portion is perpendicular to the surface of the target soil.
The penetration portion is moved while maintaining the detection posture, and the reaction force detection portion detects an increase in the reaction force received by the penetration portion when the cross-sectional area increasing portion passes through the surface of the target soil and enters the target soil.
Soil reaction force detection device. A penetration portion having an increasing cross-sectional area portion in which the cross-sectional area of a cross section perpendicular to the axial direction increases as the axial direction proceeds from the tip side to the base end side, and at least the increasing cross-sectional area portion penetrates into the soil;
A moving mechanism that moves the penetration portion along the axial direction to penetrate the penetration portion into the soil;
A moving mechanism holding unit that holds the moving mechanism;
A reaction force detection unit that continuously detects a reaction force that the penetration unit receives from the soil;
a mounting portion provided on the moving mechanism holding portion and defining a ground reference plane perpendicular to the axial direction;
an angle detection unit that detects an angle of the axial direction with respect to a vertical direction;
an operation unit that accepts an operation to set any one of the angles detected by the angle detection unit as a reference angle;
a movement mechanism control unit that stops the movement mechanism when the angle detected by the angle detection unit is not within a predetermined range including the reference angle;
Equipped with
Before detection begins, the installation portion is brought into contact with the surface of the target soil, so that the surface of the target soil and the ground reference plane are parallel to each other, and the axial direction of the penetration portion is perpendicular to the surface of the target soil.
The penetration portion is moved while maintaining the detection posture, and the reaction force detection portion detects an increase in the reaction force received by the penetration portion when the cross-sectional area increasing portion passes through the surface of the target soil and enters the target soil.
Soil reaction force detection device. A soil reaction force detection method using a soil reaction force detection device comprising: a penetration portion having an increasing cross-sectional area portion in which the cross-sectional area of its cross section perpendicular to the axial direction increases as it moves from the tip end to the base end in the axial direction, and in which at least the increasing cross-sectional area portion is inserted into soil; a reaction force detection portion that detects a reaction force received by the penetration portion from the soil; and an installation portion that defines a ground reference plane perpendicular to the axial direction,
Before starting detection, the installation portion is brought into contact with the surface of the target soil so that the surface of the target soil and the ground reference plane are parallel to each other and the axial direction of the penetration portion is perpendicular to the surface of the target soil.
While maintaining the detection posture, the cross-sectional area increasing portion is caused to pass through the surface of the target soil and enter the target soil, and the reaction force detection portion detects an increase in the reaction force received by the penetration portion ;
The reaction force detected by the reaction force detection unit is integrated in a measured section, which is a predetermined section during the movement of the penetration portion, and the integrated value is set as the characteristic value of the target soil.
Soil reaction force detection method. The method is characterized in that the increase amount or increase gradient of the reaction force detected by the reaction force detection unit is calculated in the actual measurement section, which is a predetermined section during the movement of the penetration part, and is set as the characteristic value of the target soil.
The method for detecting a soil reaction force according to claim 17. The reaction force detected by the reaction force detection unit at a predetermined penetration depth of the penetration portion to which the penetration portion has moved is calculated and set as a characteristic value of the target soil.
The method for detecting a soil reaction force according to claim 17. A penetration depth when the reaction force detected by the reaction force detection unit reaches a predetermined value is calculated and set as a characteristic value of the target soil.
The present invention is characterized in that it comprises
The method for detecting a soil reaction force according to claim 17.

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