JPH0372763B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to the improvement of a soil improvement method and equipment used when constructing consolidation columns underground for soil improvement, etc. , it is possible to improve the stirring and mixing of the excavated soil and the soil stabilizer without increasing the size of the equipment, and it is also possible to prevent the soil stabilizer injected into the ground from spreading into the ground, This invention relates to a ground improvement method and device that can create strong consolidated columns in the ground.

[Prior art] In order to improve unstable ground, a screw having a head at the tip of a rotating shaft is installed, and while excavating a predetermined ground with this screw, a soil stabilizer (for example, cement milk, water glass, high molecular materials,
There are known construction methods and devices for injecting air mortar (air mortar, etc.) from the tip of the stirring tool, stirring and mixing the mixture underground, and creating consolidation columns for ground improvement in the ground.

[Problems to be Solved by the Invention] Incidentally, when excavating the ground, it is necessary to drive the rotating shaft with a predetermined excavation torque.
Therefore, the shaft is rotated by a drive device, and there is an inversely proportional relationship between the rotational speed and torque of the driving force taken out from this drive device, and the torque is large when rotating at low speed, and when rotating at high speed. Sometimes the torque is small. At this time, if a large-sized drive device with a large output is used, both high-speed rotation and large torque can be obtained, but this increases the weight and cost of the drive device. Furthermore, the use of large drive devices increases the size and weight of the cranes that support the drive devices, creating a vicious cycle that synergistically increases the size and weight of the entire device, leading to a rise in costs. be. Therefore, when considering excavation, it is advantageous to extract the driving force from a small-sized drive device at low speed rotation because it is possible to obtain a large torque without requiring a large-sized drive device.

However, stirring and mixing treatment using low-speed rotation is insufficient for highly adhesive soil. this is,
This is because the excavated soil adheres to the stirring blades and causes them to rotate. For this reason, although the stirring time is increased during processing, poor stirring often occurs. In addition, when rotating at low speed, the soil stabilizer leaks to the outside, resulting in a further inconvenience that the strength decreases after construction. In this case, if the rotation speed is set to high speed, sufficient agitation and mixing can be achieved and the above-mentioned disadvantages can be resolved. The disadvantage is that it cannot be obtained.

Furthermore, as a soil improvement device,
There is a disclosure in Publication No. 504. The ground improvement device disclosed in this publication is provided so that the rotational trajectory drawn by the farthest end of the stirring blade, which is an excavation tool, is located outside the rotational trajectory drawn by the farthest end of the stirring blade, which is an excavation tool, and is provided with a discharge port. The caking agent, which is a soil stabilizer injected from the injection port, is disturbed by a stirring blade, and the disturbed caking agent and the surrounding ground to which no caking agent has been injected are stirred by the stirring blade. death,
This is to consolidate the entire area of soft ground.

Therefore, the ground improvement device disclosed in this publication is
This is different from the construction method that creates solidified pillars in the ground. Furthermore, even if an attempt is made to create a consolidation column in the ground using the soil improvement device disclosed in this publication, the consolidation agent, which is a soil stabilizer injected into the ground in order to consolidate the entire area of the soft ground, cannot be used. Since this caking agent is mixed with the surrounding ground by stirring, the caking agent is unnecessarily diffused into the surrounding ground, resulting in a decrease in strength after construction, making it difficult to create strong consolidation pillars. There are some inconveniences that cannot be gained.

[Purpose of the Invention] Therefore, the present invention was devised in order to eliminate the disadvantages in view of the above-mentioned actual situation, and to improve the stirring and mixing of excavated soil and soil stabilizer without increasing the size of the equipment. A soil improvement method that can prevent the soil stabilizer injected into the ground from spreading unnecessarily to the surrounding ground, and create strong consolidation columns in the ground for soil improvement. The purpose is to realize the construction method and its equipment.

[Means for Solving the Problems] In order to achieve this object, the present invention excavates the ground in a cylindrical shape by immersing a low-speed rotating excavation tool into the ground, and then rotates around the excavation axis. While moving, a stirring tool rotating at high speed is injected into the cylindrical excavated soil within the area excavated by the excavating tool while following the excavation of the ground by the excavating tool. The excavated soil and the soil stabilizer injected into the excavated soil are stirred and mixed in the cylindrical excavated soil to create a consolidated column in the ground, Further, an excavating tool is provided at the lower end of an excavating shaft which is rotated at low speed by a first drive device which is supported by a pillar so as to be able to rise and fall freely, and is connected to the excavating shaft in parallel with the excavating shaft and rotates around this excavating shaft. A stirring tool is provided at the lower tip of the stirring shaft that follows the elevation and descent of the excavation shaft and is rotated at high speed by a second drive device, and the farthest end of this stirring tool is attached to a circle within the range excavated by the excavation tool. A discharge port for a soil stabilizer to be injected into the columnar excavated soil is provided, and the stirring tool is placed above the excavating tool, and the rotation locus drawn by the farthest end of the stirring tool is the same as the rotation trajectory drawn by the farthest end of the digging tool. It is characterized by being arranged so as to be located within the rotation locus.

[Operation] According to the configuration of the present invention, the first excavation device excavates the ground in a cylindrical shape by immersing the excavation tool provided at the lower end of the excavation shaft rotating at a low speed into the ground.
Next, the stirring tool is connected to the digging shaft in parallel with the digging tool, rotates around the digging shaft, follows the elevation and descent of the digging shaft, and is provided at the lower tip of the stirring shaft, which is rotated at high speed by a second drive device. While injecting the soil stabilizer into the cylindrical excavated soil within the range excavated by the excavating tool from the discharging port at the farthest end of the excavating tool, The excavated soil and the soil stabilizing material injected into the excavated soil are stirred and mixed in the cylindrical excavated soil using a high-speed rotating stirring tool arranged so that the rotary locus drawn by the farthest end is located at the cylindrical excavated soil. Consolidation pillars will be created inside.

[Example] Next, an example of the present invention will be described in detail based on the drawings.

In the figure, 2 is a self-propelled vehicle with a caterpillar that supports and moves the support column 4, and 6 is a first drive device that is hydraulically or electrically driven. This first drive device 6
is suspended from the upper end of the column 4 so that it can be raised and lowered, and is held on the side surface of the column 4 via a holding guide 8 so that it can be raised and lowered. The first drive device 6 is interlocked with the upper end of a drive shaft 10 extending in the vertical direction. The drive shaft 10 is driven by the first drive device 6 and rotates at a low speed (60 revolutions/minute or less, preferably 10 to 30 revolutions/minute) for reasons described later. on the other hand,
As shown in FIG. 2, the excavation shaft 10 is held at its lower side by a steady rest 12 provided at the lower part of the support column 4, and is further provided with an excavation tool 16 having an excavation blade 14 at its lower tip. The excavating tool 16 is provided on both sides of the excavating shaft 10 so as to project upwardly. When the excavating tool 16 is rotationally driven by the first drive device 6 to excavate the ground in a cylindrical shape, the rotation speed of the first drive device 6 is reduced to obtain a large torque in order to obtain the required excavation torque. That's what I do.

A plurality of coupling bodies 18 are provided on one side of the drive shaft 10 in the vertical direction of the drive shaft 10. The connecting body 18 projects substantially horizontally from the excavation shaft 10, and rotatably holds a stirring shaft 20 extending vertically in parallel with the excavation shaft 10 at its horizontal tip. The upper end of the stirring shaft 20 is operatively connected to a second drive device 22 provided above the excavation shaft 10. On the other hand, the stirring shaft 20 is inserted downward into the steady rest 12, as shown in FIG. As a result, the stirring shaft 20 is connected to the excavation shaft 10 in parallel with the excavation shaft 10, and moves up and down while rotating around the excavation shaft 10 and following the up and down movements of the excavation shaft 10.
Further, the stirring shaft 20 has a lower tip located above the excavating tool 16, and is provided with a plurality of stirring tools 24. The stirring tools 24 are provided in multiple stages, protruding substantially horizontally from both sides of the stirring shaft 20. In this case, the stirring shaft 20, which is the center of rotation of the stirring tool 16, is arranged so that the rotational trajectory 24l drawn by the farthest end 24e of the stirring tool 24 is located within the rotational trajectory 16l drawn by the farthest end 16e of the excavating tool 16. is supported by the connecting body 18. By the way, since the connecting body 18 is integrally attached to the excavation shaft 10,
The connecting body 18 also rotates in conjunction with the rotation of 0. Therefore, the stirring shaft 20 and the stirring tool 24 held by the connecting body 18 rotate around the excavation shaft 10.

Further, the farthest ends 24e of the stirring tools 24 are each provided with a discharge port 26 for the soil stabilizer. In order to pour out the soil stabilizer from the discharge port 26 into the excavated soil excavated in a cylindrical shape by the excavator 16, the stirring shaft 20 and the agitator 24 are formed into a hollow cylindrical shape and communicated with each other to stabilize the soil quality. Configures a passageway for supplying the agent.

When stirring and mixing the excavated soil and the soil stabilizing material in the excavated soil using the stirring tool 24, the soil stabilizer injected into the cylindrical excavated soil does not leak to the outside from the cylindrical excavated soil. The stirring shaft 20 is rotated at high speed (60 to 150 revolutions/minute) in order to improve stirring and mixing, such as to prevent this or to increase the strength after construction. At this time, since a large torque is not required unlike when excavating, the second drive device 22
The torque of the engine is reduced to obtain high speed rotation. This second drive device 24 is integrally attached to one side of the excavation shaft 10 and is rotated around the excavation shaft 10 in conjunction with the rotation of the excavation shaft 10. Further, the second drive device 24 is raised and lowered in conjunction with the raising and lowering of the excavation shaft 10, and the stirring shaft 20 is raised and lowered following the excavation shaft 10.

In addition, in the above embodiment, the case where the excavating tool 16 and the stirring tool 24 are parallel is mentioned, but the invention is not limited to this, and the stirring tool 24 may be disposed at right angles or inclined to the excavating tool 16. Of course, it is possible.

Since the present invention is constructed as described above, it operates as follows.

The self-propelled vehicle 2 with a capillary is driven and the entire device is placed in a position to create a consolidation column for predetermined ground improvement.Then, the column 4 is supported approximately perpendicularly to the ground, and the column 4 is Excavation shaft 1 supported so that it can be raised and lowered
0. The excavating tool 16, stirring shaft 20, stirring tool 24, etc. are erected perpendicularly to the ground. Thereafter, the first drive device 6 is driven to rotate the excavation shaft 10 and the like, and the rotating excavation tool 16 is lowered to the ground surface. (Figure 3A).
Since the excavating tool 16 is equipped with an excavating blade 14, the excavating tool 16 sinks into the ground as the excavating tool 16 rotates, and excavates the ground in a cylindrical shape.

At this time, in order to immerse the excavation tool 16 into the ground while excavating the ground in a cylindrical shape, the excavation shaft 1
0 is lowered along the support column 4. The excavating tool 16 is rotated at a low speed so that a predetermined excavating torque is obtained. By rotating at a low speed, the first drive device 6 can be used even with a small output, and the use of the first drive device 6 with a small output has the advantage of reducing the size and weight of the device itself.

When the excavating tool 16 is immersed in the ground, the excavating tool 1
Following the descent of the excavator 6, the multi-stage stirring tool 24 located above the excavator 16 also descends, rotating around the excavation shaft 10 and stirring into the cylindrical excavated soil within the range excavated by the excavator 16. immerse yourself in Multiple stirring tools 24
While descending, the soil stabilizer is injected from the discharge port 26 into the cylindrical excavated soil within the area excavated by the excavator 16 to prevent diffusion, thereby stabilizing the excavated soil and the soil injected into the excavated soil. The excavating agent is stirred and mixed in the excavated soil (Fig. 3B). At this time, the excavating tool 16 is rotating at a low speed,
The stirring tool 24 rotating at high speed above the digging tool 16 can stir the excavated soil even if it is attached to the digging tool 16, so that the stirring and mixing of the excavated soil and the soil stabilizer in this excavated soil can be achieved. It becomes possible to In addition, during stirring, high torque is not required as during excavation, so even a low-output drive device can rotate at high speed, making the second drive device 22 more compact.
It becomes possible to reduce the weight. Furthermore, the high-speed rotation of the stirring tool 24 prevents the soil stabilizer from leaking to the outside, increasing the strength after construction. By stirring and mixing, it is possible to prevent unnecessary diffusion of the soil stabilizer and create strong consolidation pillars in the ground.

While performing the above-described operations continuously, excavation is carried out to a predetermined depth, and the excavated soil and soil stabilizer are stirred and mixed, and when the predetermined depth is reached, the descent of the excavating tool 16 is completed (third Figure C).

Then, in turn, the excavating tool 16 and the like are raised. At this time, the excavating tool 16 is rotated, but it may be raised while being rotated in the opposite direction to when it is lowered (FIG. 3D). When raising the excavator 126, the excavator 126 does not require any excavating torque, so the excavator 16 can be rotated at high speed. After such a process, the excavating tool 16 and the like are pulled out from the ground.
In this case, the stirring tool 24 rises and rises following the rise and fall of the excavating tool 16, and is extracted from the ground. The work is completed by pulling out the excavating tool 16 from the ground (Fig. 3E). And drilling tool 1
Consolidation pillars will be constructed on the ground after the 6th grade is extracted.

Note that by forming the excavating tool 16 in a spiral shape, it can be easily immersed into the ground.

Further, a balancer may be provided at a position on the other side of the excavation shaft 10 that is symmetrical to the position of the second drive device 22 provided on one side of the excavation shaft 10, as shown by a two-dot chain line in FIG. . This makes it possible to stabilize the rotation of the excavation shaft 10 and improve excavation and stirring and mixing. Furthermore, as shown by the two-dot chain line in FIG. A shaft/stirring device may be provided and rotated in the opposite direction to the second drive device 22 and the like. This makes it possible to stabilize the rotation and improve the efficiency of stirring and mixing, thereby making the excavation and stirring and mixing even better.

[Effects of the Invention] As is clear from the above detailed description, according to the present invention, the first excavation device immerses the excavation tool provided at the lower tip of the excavation shaft rotating at a low speed into the ground, thereby forming the ground into a cylindrical shape. to drill. Next, a stirring tool is provided at the lower tip of a stirring shaft that is connected to the drilling shaft in parallel with the drilling shaft, rotates around the drilling shaft, follows the elevation and descent of the drilling shaft, and rotates at high speed by a second drive device. While injecting the soil stabilizer into the cylindrical excavated soil in the area excavated by the excavation tool from the discharging port at the farthest end of the excavation tool, The excavated soil and the soil stabilizing material injected into the excavated soil are stirred and mixed in the cylindrical excavated soil by a high-speed rotating stirring tool arranged so that the rotation locus drawn by the farthest end is located. Consolidation pillars are created in the area, which eliminates the problems of leakage of soil stabilizer to the outside and loss of strength after construction.
Unnecessary diffusion of soil stabilizers can be prevented and strong consolidation pillars can be created. In addition, even if the excavated soil adheres to the excavating tool that rotates at low speed, the soil stabilizer discharge port placed above the excavating tool and the stirring tool that rotates at high speed will ensure that the excavated soil adhering to the excavating tool is removed. It can be stirred, and even soil with strong adhesiveness can be stirred and mixed well. Coupled with this, in order to achieve the above effect, the excavating tool is rotated at low speed by the first drive device, so it has a large torque, and the specified amount necessary for excavation can be achieved without increasing the size of the first drive device. Torque can be easily obtained. Moreover, when stirring and mixing, high torque is not required as during excavation, so even when the stirring tool is rotated at high speed by the second drive device, there is no need to increase the size of the second drive device.

In this way, it is possible to prevent the first and second drive devices from increasing in size, and it is possible to avoid the increase in weight and cost associated with an increase in the size of the drive device. It is possible to create consolidation columns for ground improvement in the ground while avoiding increases in size, weight, and cost of the entire supporting device.

[Brief explanation of drawings]

The figures show an embodiment of the invention, with Figure 1 being an overall side view of the device, Figure 2 being an enlarged view of the main parts, and Figures 3 A to E.
FIG. 2 is a schematic explanatory diagram showing the order of steps. In the figure, 4 is a column, 6 is a first drive device, 1
0 is a drilling shaft, 16 is a drilling tool, 18 is a connecting body, 20
is a stirring shaft, 22 is a second drive device, 24 is a stirring tool,
26 is a discharge port.

Claims (1)

[Claims] 1. The ground is excavated in a cylindrical shape by immersing a low-speed rotating excavation tool into the ground, and then the excavation tool follows the excavation of the ground by the excavation tool while rotating around an excavation axis. A soil stabilizer is injected into the cylindrical excavated soil within the range excavated by the excavation tool, and a stirring tool that rotates at high speed is immersed into the cylindrical excavated soil, thereby adding to the excavated soil and the excavated soil. A ground improvement method characterized in that a consolidation column is created in the ground by stirring and mixing the injected soil stabilizer in the cylindrical excavated soil. 2. An excavating tool is provided at the lower end of an excavating shaft that rotates at low speed by a first drive device that is supported by a pillar so as to be able to rise and fall freely, and is connected to the excavating shaft in parallel with the excavating shaft and rotates around this excavating shaft. A stirring tool is provided at the lower end of the stirring shaft that follows the elevation and descent of the excavation shaft and is rotated at high speed by a second drive device, and the farthest end of this stirring tool has a cylindrical shape within the area excavated by the excavation tool. A discharge port for a soil stabilizer to be injected into the excavated soil is provided, and the stirring tool is placed above the excavating tool, and the rotation locus drawn by the farthest end of the stirring tool is the same as the rotation drawn by the farthest end of the digging tool. A ground improvement device characterized by being arranged to be located within the locus.