JPS6117632A - Method and apparatus for improving ground - Google Patents

Abstract

PURPOSE:To prevent the lowering of the strength of the ground by a method in which the ground is excavated by an excavator being turned at low speed, and a soil stabilizer is injected into the excavated soil and mixed with the excavated soil by a stirrer being turned at high speed. CONSTITUTION:A driver is operated to turn the excavating shaft 10 at low speeds, and the ground is excavated by the blade 14 of an excavator 16. As the excavator 16 is lowered, the stirring blade 24 being turned at high speeds is also lowered, and a soil stabilizer is injected from a nozzle 26 into the excavated soil and mixed with the excavated soil with stirring. The driver can thus be used with small output since it is turned at low speed, and the miniaturization and weight reduction of the device can be attained. Since the stirring blade 24 is turned at high speed, the leak of soil stabilizer to the outside and the lowering of the strength of the ground after being improved can be prevented.

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. The present invention relates to a ground improvement method and device that can improve the stirring and mixing of excavated soil and soil stabilizer without increasing the size of the device.

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

[Problems to be Solved by the Invention] By the way, when excavating the ground, it is necessary to drive the rotating shaft with a predetermined excavation torque. Therefore, the shaft is driven by a drive device, and there is an inversely proportional relationship between the rotational speed and torque of the driving force extracted from this drive device, and the torque is large when rotating at low speed, and when rotating at high speed. The torque will be 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, in consideration of excavation, it is advantageous to extract the driving force from a small-sized drive device at low speed rotation, since 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 because the excavated soil adheres to the stirring blades. For this reason, although the stirring time is increased during processing, poor stirring often occurs. In addition, when rotating at low speeds, the soil stabilizer leaks to the outside, resulting in a decrease in strength 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.However, if the rotation speed is set to high speed, as mentioned above, unless the drive device is made large and has a large output, it is difficult to obtain a large excavation torque. There is an inconvenience that it is not possible.

[Purpose of the Invention] In view of the above-mentioned circumstances, the present invention was devised to eliminate the disadvantages, and to improve the stirring and mixing of excavated soil and soil stabilizer without increasing the size of the equipment. The object of the present invention is to realize a ground improvement method and device that can create consolidation columns for ground improvement in the ground.

[Means for Solving Problem 8] In order to achieve this object, the present invention excavates the ground with a digging tool that rotates at a low speed, and then uses a stirring tool that rotates at a high speed while injecting a soil stabilizer into the excavated soil. The method is characterized in that the excavated soil and the soil stabilizer are mixed by stirring, and
An excavation tool is provided at the tip of an excavation tool that is supported so as to be freely raised and lowered and rotates at a low speed, and a soil stabilizer discharge port and a stirring tool are provided at the end of a stirring shaft that follows the elevation and descent of the excavation tool and rotates at a high speed, A feature of the present invention is that the discharge port and the stirring tool are disposed above the excavating tool.

[Operation] According to the present invention, first, the ground is excavated with an excavator that rotates at a low speed. Next, the soil stabilizer is injected into the excavated soil from the discharge port provided at the tip of the stirring shaft that rotates at high speed and is placed above the excavation tool, and the excavated soil and soil stabilizer are mixed together by the stirring tool that rotates at high speed. The mixture is stirred and solidified pillars are created in the ground.

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

In the figure, 2 is a self-propelled vehicle with caterpillars that supports and moves the support column 4. Reference numeral 6 denotes a first drive device of a hydraulic or electric type, and the first drive device 6 is suspended from the upper end of the support column 4 so as to be able to rise and fall freely, and is attached to the support column 4 via a holding guide 8.
It is held on the side so that it can be raised and lowered freely. 10 is a drive shaft extending in the vertical direction, the upper end of the drive shaft 10 is interlocked and connected to the first drive device 6, and the drive shaft IO is driven by the first drive device 6 for reasons described later. It is rotated at low speed (60 rotations or less, preferably 10 to 30 rotations/minute). . On the other hand, the lower part of the excavation shaft 10 is held by a steady rest 12 provided at the lower part of the support column 4, and furthermore, an excavation tool 16 having an excavation blade 14 is provided at the 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 driven by the first drive device 6 to excavate the ground, the rotation speed of the first drive device 6 is reduced to obtain a large torque in order to obtain the required excavation torque.

In one example of the drive shaft 10, a plurality of coupling bodies 18 are provided in the vertical direction of the drive shaft 10. This connecting body 18 is
It protrudes substantially horizontally from the excavation shaft 10, and a stirring shaft 20 extending vertically parallel to the excavation shaft 10 is rotatably held at the 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, below the stirring shaft 20 is the steady rest 12.
A plurality of agitating tools 24 are provided with the lower tip portion thereof being positioned above the excavating tool 16 . The stirring tools 24 are provided in a plurality of stages, protruding substantially horizontally from both sides of the stirring shaft 20. In this case, the farthest end 16e of the digging tool 16
The stirring shaft 20, which is the center of rotation of the stirring tool 16, is held by the connecting body 18 so that the rotational trajectory 24Il drawn by the farthest end 24e of the stirring tool 24 is located within the rotational trajectory 16β drawn by the stirring tool 16. By the way, since the coupling body 18 is integrally attached to the excavation shaft 10, the coupling body 18 also rotates in conjunction with the rotation of the excavation shaft 10. Therefore, the stirring shaft 20 and the stirring tool 24 held by the connecting body 18 rotate around the excavation shaft 10.

Furthermore, the farthest ends 24e of the stirring tools 24 are provided with discharge ports 26 for the soil stabilizer, respectively. In order to pour out the soil stabilizer into the excavated soil from the discharge port 26, the stirring shaft 20
The and stirring tool 24 are formed into a hollow cylinder shape and communicated with each other to form a passage for supplying the soil stabilizer.

When stirring and mixing the excavated soil and the soil stabilizer using the stirring tool 24, the stirring is performed in order to improve the stirring and mixing, such as preventing leakage of the soil stabilizer to the outside or increasing the strength after construction. The shaft 20 is rotated at high speed (60 to 150 revolutions/minute). At this time, unlike when excavating, a large torque is not required, so the torque of the second drive device 22 is reduced to obtain high-speed rotation. This second drive device 2
4 is integrally attached to one side of the excavation shaft 10, and
It rotates around the excavation axis in conjunction with the rotation of 0. Further, the stirring shaft 20 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 digging tool 16 and the stirring tool 24
Although the case where the excavating tool 16 and the excavating tool 16 are parallel to each other has been described, the invention is not limited to this, and it goes without saying that the agitating tool 24 may be arranged at right angles to or at an angle to the excavating tool 16.

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

The self-propelled vehicle 2 with a caterpillar is run, and the entire device is installed at a position where a consolidation column is to be created to start the specified ground improvement.Then, the column 4 is supported approximately vertically to the ground, and the column 4 is An excavation shaft 10° that is supported so that it can be raised and lowered, an excavation tool 16, an agitation shaft 20, an agitation tool 24, etc. are erected perpendicularly to the ground. After that, the first
The driving device 6 is driven to rotate the excavation shaft 10, etc., and the rotating excavation tool 16 is lowered to the ground surface (Fig. 3 (A)
).

Since the excavator 16 is equipped with the excavator blade 14, the ground is excavated as the excavator 16 rotates. At this time, drilling tool 1
6 into the ground while excavating the ground, the first drive device 6 connected to the upper end of the excavation shaft IO is lowered along the support column. 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. - Next, when the excavating tool 16 is immersed, the multiple stages of stirring tools 24 located above the excavating tool 16 also descend following the descent of the excavating tool 16, and are immersed into the excavated soil. While descending, the plurality of stirring tools 24 pour out the soil stabilizer into the excavated soil from the discharge ports 26, stirring and mixing the excavated soil and the soil stabilizer well (Fig. 3 (B)).
).

At this time, the digging tool 16 is rotating at a low speed;
The stirring tool 24 above G that rotates at high speed can stir the excavated soil even if the excavated soil is attached to the excavating tool 1G, so it is possible to improve the stirring and mixing of the excavated soil and the soil stabilizer. . Moreover, since high torque is not required during stirring as during excavation, even a low-output drive device can rotate at high speed, making it possible to reduce the size and weight of the drive device.

The above-mentioned operations are continuously performed to excavate 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, etc. is completed ( Figure 3 (C)).

Then, in turn, the excavating tool 16 and the like are raised.

At this time, the excavating tool I6 is rotated, but it may be raised while being rotated in the opposite direction to that when descending (Fig. 3-(D)). , it is also possible to rotate the digging tool 16 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 follows the rise and fall of the excavating tool 16, rises, and is extracted from the ground. The work is completed by pulling out the excavating tool 16 etc. from the ground (Fig. 3 (E)). Then, after the excavating tool 16 and the like are pulled out, a consolidation column will be created.

Note that by forming the excavating tool 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 second drive device 22 provided on the - side of the excavation shaft 10, as shown by the two-dot chain line in FIG. Thereby, the rotation of the excavation shaft 10 can be stabilized, and excavation and stirring and mixing can be performed well.

In addition, a third drive device as a balancer, a stirring shaft/stirring device, etc., is installed as a balancer at a position symmetrical to the second driving device 22, stirring shaft 20, and stirring tool 24 on the other side of the excavation shaft 10, as shown by the two-dot chain line in FIG. A tool may be provided to rotate the second drive device 22 and the like in the opposite direction. Thereby, the rotation can be stabilized and the efficiency of stirring and mixing can be improved, so that excavation and stirring and mixing can be made even better.

[Effects of the Invention] As is clear from the above detailed description, according to the structure of the present invention, the agitation and mixing of the excavated soil and the soil stabilizer is carried out by a high-speed rotating agitation disposed above a low-speed rotating excavator. Since this is done with a tool, it is possible to eliminate the inconvenience of leakage of soil stabilizer to the outside and decrease in strength after construction. In addition, even if the excavated soil adheres to the excavating tool that rotates at a low speed, the excavated soil that has adhered to the excavating tool can be reliably removed by the soil stabilizer discharge port placed above the excavating tool and the stirring tool 12 that rotates at high speed.・It can be stirred and the stirring and mixing can be improved even for highly sticky soil. In conjunction with this, in achieving the above effects,
Since the excavator rotates at a low speed, it has a large torque, and the predetermined torque required for excavation can be easily obtained without increasing the size of the drive device. Moreover, since high torque is not required during stirring and mixing as in the case of excavation, there is no need to increase the size of the drive device even when the stirring tool is rotated at high speed.

In this way, it is possible to prevent the drive device from increasing in size, and it is possible to avoid the increase in weight and cost associated with the increase in the size of the drive device. This has the effect of making it possible to create consolidated pillars for ground improvement in the ground while avoiding increases in size, weight, and even higher costs.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention; FIG. 1 is an overall side view of the device, FIG. 2 is an enlarged view of the main parts, and FIGS. 3 (A) to (E) are schematic explanatory diagrams showing the order of steps. . In the figure, 4 is a column, 6 is a first drive device, 10 is an excavation shaft, 16 is an excavation tool, 18 is a connecting body, 20 is a stirring shaft, 22
24 is a stirring tool, and 26 is a discharge port. Agent Patent Attorney Yoshimi Saigo Agent Patent Attorney Hara 1) Yukio 1c, n- Engraving of the drawings (no changes to the contents) Figure 1 Figure 2''i Figure 3 (A) (B) (C) ( ()) (E) Procedural amendment written format) % formula % 1. Indication of the case 1982 Patent Application No. 137926 2. Name of the invention Ground improvement method and device 3. Related Patent Applicant Address: 3-1-6 Isobe, Chiba City, Chiba Prefecture Name: Hideo Tezawa 4, Agent: 105 TEt 03-438
-2241 (Representative) Address: 3 Toranomon, Minato-ku, Tokyo
No. 4-17 Kokuto 3rd Building, 4th Floor 5, Date of amendment order: Voluntary 6, Drawing subject to amendment (no change in content)

Claims (1)

[Scope of Claims] 1. Excavating the ground with a low-speed rotating excavator, and then stirring and mixing the excavated soil and the soil stabilizer with a high-speed rotating stirring tool while injecting a soil stabilizer into the excavated soil. A ground improvement method characterized by: 2. An excavation tool is provided at the tip of an excavation tool that is supported so as to be able to rise and fall and rotates at a low speed, and a soil stabilizer discharge port and a stirring tool are provided at the tip of a stirring shaft that follows the elevation and descent of the excavation tool and rotates at a high speed. A ground improvement device characterized in that the discharge port and the stirring tool are arranged above the excavating tool.