JPH046812B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to improvements in a soil improvement method and equipment used when constructing consolidation columns underground for soil improvement, etc. It simplifies the process, reduces weight, achieves good mixing and agitation, and also prevents the soil stabilizer injected into the ground from spreading into the surrounding ground, resulting in strong consolidation in the ground. This article relates to a ground improvement method and equipment for constructing pillars.

[Prior Art] In order to improve unstable ground, a soil stabilizer (for example, cement milk, water glass, etc.) is applied to the tip of a rotating shaft while excavating the ground with a screw having a head provided at the tip of the shaft. A construction method and an apparatus for creating a consolidation column in the ground by pouring excavated soil and a soil stabilizer into the ground and stirring and mixing them underground are known.

[Problems to be Solved by the Invention] By the way, in the conventional construction method and its equipment, in order to stir and mix while excavating, for example, an excavator, a stirring tool, and a soil stabilizing tool are attached to the tip of the rotating shaft. Some are equipped with a discharge port for the agent. However, in the past, the excavating tools and the like were arranged in a concentrated manner, resulting in a complicated structure and increased weight. Moreover, when attempting to obtain the required excavation torque by reducing the rotation speed of the drive device to rotate these heavy excavation tools during ground excavation, the reduction in rotation speed requires a long time for stirring and mixing, and the soil quality There is an inconvenience that the stabilizer leaks to the outside, which may result in poor stirring. Therefore, in order to obtain large torque and high speed rotation, it is necessary to provide a large-sized drive device with a large driving force, resulting in the inconvenience of increasing the size and weight of the entire device.

Alternatively, there is a method in which a stirring tool that rotates at high speed is placed above the excavating tool that has a discharge port for the soil stabilizer, and this stirring tool is rotated around the excavation shaft along with the rotation of the excavating tool, but this method also has a different structure. Because it is complex, it is also heavy. For this reason, it had the above-mentioned disadvantages.

Furthermore, as a ground improvement device,
Some of these are disclosed in Publication No. 120412 and Japanese Unexamined Patent Publication No. 105110/1983. The ground improvement devices disclosed in these publications inject a soil stabilizer such as a soil conditioner or a coagulant into the ground, and solidify the ground by stirring and mixing the soil stabilizer and the ground. However, the soil improvement devices disclosed in these publications all stir and mix the soil stabilizer injected into the ground and the ground around the soil stabilizer to which no soil stabilizer has been injected, and then spread the soil over the entire area of the ground. It solidifies. For this reason, the ground improvement devices disclosed in these publications are different from construction methods that create consolidation columns in the ground. Even if the soil improvement devices disclosed in these publications are used to create consolidation pillars in the ground, the soil stabilizer injected into the ground and the ground surrounding the soil stabilizer are stirred and mixed. The problem is that the soil stabilizer is needlessly spread into the surrounding ground, resulting in a decrease in strength after construction, making it impossible to construct strong consolidation columns.

[Object of the invention] Therefore, the object of the present invention is to solve such problems, simplify the structure, reduce the weight, achieve good stirring and mixing, and provide a soil stabilizer injected into the ground. The purpose of the present invention is to realize a ground improvement method and device that can prevent the waste from spreading into the surrounding ground and create strong consolidated pillars in the ground.

[Means for solving the problem] In order to achieve this object, the present invention immerses a low-speed rotating excavation tool into the ground, lowers it to a predetermined depth, stops, and then raises it while rotating. The ground is excavated twice in a cylindrical shape, and after the excavation tool is removed from the ground, soil quality is extracted from the lower discharge port of the stirring tool that rotates at high speed into the cylindrical excavated soil within the area excavated by the excavation tool. A stabilizer is injected, and then the high-speed rotating stirring tool is immersed into the cylindrical excavated soil, lowered to a predetermined depth, stopped, and raised while rotating to separate the excavated soil and the excavated soil. The method is characterized in that a consolidated column is created in the ground by stirring and mixing the soil stabilizer injected into the soil twice in the cylindrical excavated soil, and it is supported on the column so as to be able to rise and fall freely. An excavation tool for excavating the ground in a cylindrical shape is installed at the lower end of the excavation shaft that rotates at low speed by the excavation drive device, and is supported by the support so that it can be raised and lowered, and is separate and parallel to the excavation shaft for stirring. The lower tip of a stirring shaft rotated at high speed by a drive device is immersed into the cylindrical excavated soil within the area excavated by the excavator, and the excavated soil and soil stabilizer are stirred in the cylindrical excavated soil. A stirring tool for mixing is provided, and a discharge port for the soil stabilizer to be injected into the cylindrical excavated soil within the area excavated by the excavating tool is provided below the stirring tool.

[Function] According to the configuration of the present invention, the excavation tool provided at the lower end of the excavation shaft rotated at low speed by the excavation drive device is immersed into the ground to first excavate the ground in a cylindrical shape, and the excavation is carried out in a predetermined manner. Once the depth is reached, the excavator stops, then rotates and rises to remove the excavator. As a result, the ground is excavated twice. Next, the cylindrical excavated soil within the area excavated by the excavation tool is inserted from the lower discharge port of the stirring tool provided at the lower tip of the stirring shaft which is parallel to the excavation shaft and rotates at high speed by a stirring drive device. Inject soil stabilizer into
A stirring tool that rotates at high speed is immersed into the cylindrical excavated soil within the area excavated by the excavating tool, and the excavated soil and the soil stabilizer injected into the excavated soil are stirred and mixed in the cylindrical excavated soil. When it reaches a predetermined depth, it stops, then rotates and raises to remove the stirring tool. As a result, the soil stabilizer is sufficiently injected into the entire area of the excavated soil within the excavated area, and the excavated soil and soil stabilizer are stirred and mixed twice to create consolidation columns in the ground. .

[Example] Next, an example of the present invention will be described in detail based on the drawings. In FIGS. 1 and 2, 2 is a self-propelled vehicle with a caterpillar that supports and moves the holding column 4, and 6 is a support suspended from the upper end of the holding column 4 by a support cable 8 so as to be movable up and down. This support 6 includes a column 10
is installed vertically. Further, an excavation drive device 12 and an agitation drive device 14, each of which is hydraulic or electric, are suspended from the support 6 so as to be able to rise and fall.
The excavation drive device 12 and the stirring drive device 14 are provided with holding guides 1 on both sides of the pillar 10, respectively.
6 and 18 so that it can be raised and lowered.

The upper end portion of an excavation shaft 20 extending in the vertical direction is interlocked and connected to an excavation drive device 12 provided on one side of the pillar 10 so as to be movable up and down. Drilling shaft 20
is rotated at low speed (less than 60 revolutions per minute, preferably 10 to
30 revolutions/minute). As shown in FIG. 3, this excavation shaft 20 is held at its lower end by a steady rest 22 provided at the bottom of the column 10, and is further provided with an excavation tool 26 having an excavation blade 24 at its lower end. A cutting blade 28 is provided. The excavating tool 26 is provided on both sides of the excavating shaft 20 so as to project upwardly. When excavating the ground in a cylindrical shape by rotating the excavating tool 26, the rotational speed of the excavating drive device 12 is reduced to obtain a large torque in order to obtain the required excavating torque.

An upper end portion of a stirring shaft 30 extending in the vertical direction is interlocked and connected to a stirring drive device 14 provided on the other side of the support column 10 so as to be able to move up and down. This stirring shaft 3
0 is provided with its axial direction parallel to the axial direction of the excavation shaft 20. As shown in FIG. 3, the stirring shaft 30 is held at its lower part by a steady rest 32 provided at the bottom of the support column 10, and furthermore, a plurality of stages of stirring tools 34 are protruded approximately horizontally on both sides of the stirring shaft 30 at the lower tip. It is set up. Each stirring tool 34 has a size that allows it to be immersed in the cylindrical excavated soil within the range excavated by the excavating tool 26, as shown in FIGS. 4E to 4H. A discharge port 36 for a soil stabilizer to be injected into the cylindrical excavated soil within the range excavated by the excavator 26 is provided below each of these stirring tools 34. In order to inject the soil stabilizer from this discharge port 36 into the columnar excavated soil excavated by the excavator 26,
A stirring tool 34 is formed into a hollow cylindrical shape and communicates with the stirring shaft 30, thereby forming a passage for supplying the soil stabilizer. In this embodiment, the stirring tool 34 is provided with a discharge port 36 to have a stirring and discharging function, but by providing a separate discharge port and communicating with the passage for supplying soil stabilizer, it is possible to remove water from the stirring tool 34. It is also possible to separate the discharge ports.

When stirring and mixing the excavated soil and the soil stabilizer in the excavated soil by the stirring tool 34, the soil stabilizer injected into the cylindrical excavated soil does not leak to the outside from the cylindrical excavated soil. The stirring shaft 30 is rotated at high speed (60 to 150 rpm) in order to improve the stirring and mixing, such as preventing this or increasing the strength after construction.
minutes). At this time, stirring and mixing does not require a large torque as in the case of excavation, so high-speed rotation can be obtained.

In this way, the excavation shaft 20 and the stirring shaft 30 are supported on the support column 10 in parallel and movably up and down, so that they are configured separately. For this reason, each axis 2
There is no need to consider the effects on each other's functions, as is the case when the shafts 20 and 30 are configured coaxially. etc. can be determined. As a result, it is possible to achieve weight reduction while improving strength.

Next, the operation of this invention will be explained.

The self-propelled vehicle 2 with a track pillar is driven and the entire device is installed at a predetermined position where a consolidation column for ground improvement is to be constructed. Next, the support column 4 supports the support column 10 substantially vertically to the ground, and the excavation shaft 20, excavation tool 26, stirring shaft 30, stirring tool 34, etc. that are supported by the support column 10 so as to be able to rise and fall are supported vertically to the ground. stand up At this time, first, the excavating tool 26 is installed at a predetermined position where a consolidation column is to be created. Next, the excavation drive device 12 is driven to rotate the excavation shaft 22, and the rotating excavation tool 26 is lowered to the ground surface (FIG. 4A). The ground is excavated in a cylindrical shape by rotating and immersing the excavating tool 26 into the ground (FIG. 4B).

At this time, in order to immerse the excavation shaft 20 into the ground while excavating the ground in a cylindrical shape, the excavation shaft 20
The excavating drive device 12 connected to the upper end of the excavator 0 is lowered along the support column 10 by the holding guide 16.
The excavation drive device 12 outputs driving force by decreasing the rotation speed and increasing the torque so that the required excavation torque can be obtained. Therefore, the excavating tool 26 is rotated at a low speed with a required excavating torque, so that the ground can be reliably excavated. Therefore, the excavation drive device 12 can be a small one with a small driving force, which can contribute to making the device smaller and lighter.

As the excavation by the excavator 26 progresses and reaches a predetermined depth, the descent of the excavator 26 is stopped (FIG. 4C). After that, the excavating tool 26 and the like are raised on the contrary. At this time, the excavating tool 26 is raised while being rotated, but may be raised while being rotated in the opposite direction to the direction in which it is lowered. When raising the excavator 26, less torque is required than when descending the excavator, so it is possible to rotate the excavator 26 at a high speed. Excavation ends by pulling out the excavation tool 26 from the ground (fourth step).
Figure D).

As a result, the ground is excavated twice in a cylindrical shape and crushed into fine pieces.

Next, the position of the support column 10 is changed using the holding column 4 of the self-propelled vehicle 2 with a caterpillar, and the stirring tool 34 is installed at a predetermined position where a consolidation column is to be formed. Stirring drive device 14
The stirring tools 34 in multiple stages are rotated and lowered onto the surface of the excavated soil. (Figure 4E). By lowering and rotating the stirring drive device 14, the stirring tool 3 is placed in the cylindrical excavated soil within the area excavated by the digging tool 26.
Immerse yourself in 4. After immersion, a soil stabilizer (e.g., cement milk, water glass, polymer material, air mortar, etc.) is supplied from the discharge port 36 provided below the stirring tool 34.
is injected into the cylindrical excavated soil within the area excavated by the excavating tool 26 to prevent diffusion, and the rotating stirring tool 34 mixes the excavated soil and the soil stabilizer injected into the excavated soil in the excavated soil. Stir and mix (Figure 4F).

At this time, since the high torque required for excavation is not required, even a small drive device with a small driving force can rotate at high speed, and by providing the multi-stage stirring tool 34, sufficient stirring and mixing can be performed.
It becomes possible to make the device smaller and lighter. Moreover, the high speed rotation of the stirring tool 34 can prevent the soil stabilizer from leaking to the outside, and can increase the strength after processing. Furthermore, by injecting the soil stabilizer into the excavated soil from the discharge port 36 provided below the stirring tool 34 immersed in the excavated soil, the soil stabilizer is injected into the entire area of the excavated soil within the range excavated by the excavating tool 26. By sufficiently injecting the soil stabilizer and stirring and mixing the excavated soil and the soil stabilizer in the cylindrical excavated soil,
It is possible to prevent wasteful diffusion of soil stabilizers and to create strong consolidation columns in the ground.

In this way, the soil stabilizer is injected into the excavated soil and stirred and mixed by the stirring tool 34, and when a predetermined depth is reached, the stirring tool 34 stops descending. (Figure 4G). Next, the stirring tool 34 is raised and pulled out from the ground. At this time, the stirring tool 34 may be raised while being rotated in the same direction as when it was lowered, or may be raised while being rotated in the opposite direction. Stirring tool 34
The stirring and mixing is completed by raising the soil and removing it from the ground (Fig. 4H).

As a result, the excavated soil and the soil stabilizer are stirred and mixed twice and kneaded well.

As a result, consolidation columns are created in the ground after the stirring tool 34 is extracted.

In this example, the soil stabilizer was added to the stirring shaft 20.
Although the injection is performed from the tip of the excavation shaft 30, it is also possible to inject from the tip of the excavation shaft 30. Further, by forming the excavating tool 26 in a spiral shape, it can be easily immersed into the ground.

[Effects of the Invention] According to the present invention, the ground is first excavated in a cylindrical shape by sinking into the ground the excavation tool provided at the lower end of the excavation shaft rotated at low speed by the excavation drive device, and Once the depth is reached, stop, then rotate and raise the excavator to remove it and dig into the ground.
It is excavated repeatedly and crushed into small pieces. Next, after removing the excavation tool, a soil stabilizer is injected into the cylindrical excavated soil within the area excavated by the excavation tool, and the agitation drive device rotates at high speed and immerses the agitation tool into the excavated soil. The cylindrical excavated soil within the excavated area and the soil stabilizer injected into the excavated soil are stirred and mixed in the cylindrical excavated soil, and when it reaches a predetermined depth, it is stopped and then raised while rotating. The stirring tool is removed, and the excavated soil and soil stabilizer are stirred and mixed twice to ensure good mixing and create consolidation columns in the ground, allowing for reliable excavation of the ground and thorough mixing. can do.
As a result, the soil stabilizer can be sufficiently injected into the entire area of the excavated soil, preventing leakage of the soil stabilizer to the outside, achieving good stirring and mixing, and increasing the strength after construction. , it is possible to prevent wasteful diffusion of soil stabilizers and create strong consolidation pillars.

Furthermore, in order to achieve the above effects, the excavating tool and the stirring tool are constructed separately, and each is rotationally driven by a separate drive device. In other words, the excavation tool is rotated at a low speed by reducing the rotation speed of the excavation drive device so that the required excavation torque can be obtained, and the stirring tool is not required to have high torque as during excavation, so the torque of the agitation drive device is reduced. Dropped and rotated at high speed. This simplifies the structure of excavating tools, stirring tools, etc., and avoids increasing the size of the excavating drive device and stirring drive device because each can be rotated by a small drive device with low driving force. can. In addition, by configuring the excavation shaft and the stirring shaft separately, there is no need to consider the effects on each other's functions, unlike when the shafts are configured coaxially. The shape, structure, etc. can be determined by considering only the functions required by the product, and the weight can be reduced while improving the strength. Therefore, it is possible to realize an apparatus that can simplify the structure of the entire apparatus, reduce its weight, and perform good stirring and mixing. Furthermore, by forming the excavating shaft or stirring shaft into a spline shaft and interlockingly connecting it to a single drive device using an endless rotation transmission device such as a chain or belt, the drive device can be shared.
As a result, further weight reduction can be achieved.

[Brief explanation of drawings]

The figures show an embodiment of the invention, with Figures 1 and 2 being an overall side view and an overall front view of the device, respectively, and Figure 3 being an overall side view and an overall front view of the device.
The figure is an enlarged front view of the main part, and FIGS. 4A to 4H are schematic explanatory diagrams showing the order of steps. In the figure, 2 is a self-propelled vehicle with a caterpillar, 4 is a holding column, 6 is a support, 10 is a column, 12 is an excavation drive device, 14 is a stirring drive device, 20 is an excavation shaft,
26 is a digging tool, 30 is a stirring shaft, 34 is a stirring tool, 3
6 is a discharge port.

Claims (1)

[Scope of Claims] 1. The ground is excavated twice in a cylindrical shape by immersing a low-speed rotating excavation tool into the ground, lowering it to a predetermined depth, stopping, and then raising it while rotating. After removing the tool from the ground, a soil stabilizer is injected into the cylindrical excavated soil within the area excavated by the digging tool from the lower discharge port of the stirring tool that rotates at high speed, and then the stirring tool rotates at high speed. The tool is immersed in the cylindrical excavated soil, lowered to a predetermined depth, stopped, and then raised while rotating, thereby transferring the excavated soil and the soil stabilizer injected into the excavated soil into the cylindrical shape. A ground improvement method characterized by creating consolidated columns in the ground by stirring and mixing column-shaped excavated soil twice. 2. An excavation tool for excavating the ground in a cylindrical shape is provided at the lower end of an excavation shaft that rotates at low speed by an excavation drive device that is supported by a support that can be raised and lowered. The lower tip of the stirring shaft, which is separate and parallel and rotates at high speed by a stirring drive device, is immersed into the cylindrical excavated soil within the range excavated by the excavating tool, and the excavated soil and soil stabilizer are mixed into the circular column. A stirring tool for stirring and mixing in the columnar excavated soil is provided, and a discharge port for the soil stabilizer to be injected into the columnar excavated soil within the range excavated by the excavating tool is provided below the stirring tool. A ground improvement device characterized by: