JPS6411773B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to improvements in a soil improvement method and device 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.

[Technical Background of the Invention] In order to create consolidation columns in the ground for soil improvement, etc., a screw having a head is provided at the tip of the stirring shaft, and the stirring shaft is rotated on the desired ground while the soil stabilizer is applied. A construction method in which cement milk, water glass, polymer materials, air mortar, etc. are poured out from the tip of the stirring shaft, stirred and mixed in the ground, and solidified pillars are created in the ground for soil improvement. and devices thereof are known.

[Problems with Background Art] By the way, when excavating the ground, a predetermined excavation torque is required. On the other hand, there is an inversely proportional relationship between the rotational speed and torque of the ground improvement device, with the torque being large when rotating at low speed and being small when rotating at high speed. At this time, if a large-sized drive device with high horsepower 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 a large drive device increases the size and weight of the crane, etc. that supports this drive device, which synergistically increases the size and weight of the entire device, creating a vicious cycle that leads to higher costs. There is. Therefore, when considering excavation, low-speed rotation is advantageous because it is possible to obtain 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 this case, it is possible to achieve sufficient agitation and mixing by rotating at high speed, but as mentioned above, there is the disadvantage that large excavation torque cannot be obtained unless the drive device is large and has high horsepower. be.

[Object of the Invention] In view of the above-mentioned circumstances, the present invention was devised to eliminate the inconveniences, and to improve the agitation 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.

[Structure of the Invention] In order to achieve this object, the present invention excavates the ground by rotating a stirring blade equipped with a digging blade at the tip of a hollow cylindrical stirring shaft at a low speed, and then adds soil quality into the excavated soil. A position where the stirring blade and rotation center rotate around the stirring shaft at the same speed as the rotation speed of the stirring blade, where the stabilizer is injected and the excavated soil and soil stabilizer are then rotated at a low speed. It is characterized by stirring and mixing with a secondary stirring blade that rotates at high speed and is equipped with a soil stabilizer discharge port and a digging blade at the tip of a hollow cylindrical stirring shaft that is supported so that it can be raised and lowered. A stirring blade that rotates at a low speed is provided, and the stirring blade follows the rise and fall of the stirring blade and is arranged at a position where the center of rotation rotates around the stirring shaft at the same speed as the rotational speed of the stirring shaft. It is characterized in that a movable sub stirring blade is arranged above the stirring blade.

[Embodiments of the Invention] Examples of the present invention will be described in detail and specifically below based on the drawings.

In the figure, 2 is a self-propelled vehicle with a track that supports and moves the support column 4. Reference numeral 6 denotes a hydraulic or electric drive device. The drive device 6 is suspended from the upper end of the column 4 so as to be able to rise and fall freely, and is also held via a holding guide 8 on the side surface of the column 4 so as to be able to move up and down. Reference numeral 10 denotes a stirring shaft extending in the vertical direction, and the upper end of the stirring shaft 10 is interlocked and connected to the driving device 6. The stirring shaft 10 is driven by the driving device 6 and rotates at a low speed for reasons described later. Dynamic (10 to 30 rotations/
minutes). On the other hand, a stirring blade 12 and a discharge port 14 for pouring the soil stabilizer into the excavated soil are provided at the lower tip of the stirring shaft 10. The above stirring blade 1
2 protrudes substantially horizontally from both sides of the stirring shaft 10. This stirring blade 12 has a function of stirring and mixing excavated soil and soil stabilizer, but in addition to this, the stirring blade 12 has a function of stirring and mixing excavated soil and soil stabilizer.
2 is equipped with an excavation blade 16, which also has the function of excavating the ground. When excavating the ground, a predetermined excavation torque is required, so the rotational speed of the stirring blades 12 is set to the above-mentioned low speed so that a large excavation torque can be obtained. The stirring shaft 10 has a hollow cylindrical shape and has a passage for supplying the soil stabilizer in order to pour out the soil stabilizer into the excavated soil through the discharge port 14.

1 and 2 show a first embodiment of the apparatus of the present invention, in which a connecting body 1 is provided above the stirring blade 12.
8 protrudes substantially horizontally from one side of the stirring shaft 10,
A sub-stirring shaft 20 extending vertically in parallel with the stirring shaft 10 is rotatably held at the horizontal tip of the connecting body 18 . A sub-stirring blade 22 is provided substantially horizontally at the lower end of the sub-stirring shaft 20 located above the stirring blade 12. . in this case,
The center of rotation of the sub-agitating blade 22 is such that the small circle of the rotating locus drawn by the farthest end of the sub-agitating blade 22 falls within the large circle of the rotating locus drawn by the farthest end of the agitating blade 12. A sub-stirring shaft 20 is held by the connecting body 18.
By the way, since the connecting body 18 is integrally attached to the stirring shaft 10, the connecting body 18 also rotates in conjunction with the rotation of the stirring shaft 10. For this reason, the connector 1
The sub-stirring shaft 20 and the sub-stirring blades 22 held at 8 rotate around the stirring shaft 10. The sub-stirring blades 22 are provided to improve the stirring and mixing of the excavated soil and the soil stabilizer.In order to improve the stirring and mixing, the sub-stirring blades 22 rotate at high speed (80 to 150 revolutions/minute). Stirring and mixing does not require high torque like in excavation, so it can be rotated at high speed with small horsepower. Furthermore, according to the results of actual use, the rotation center of the sub-stirring blade 22, that is, the mounting angle between the sub-stirring shaft 20 and the stirring blade 12, when the mounting angle θ in FIG. 7 is about 45 degrees, is as follows. It became clear that the best agitation mixing was obtained. 24 is a sub-drive device connected to the upper end of the sub-stirring shaft 20;
As described above, since the sub-agitating blades 22 can be rotated with a small horsepower, the sub-driving device 24, which is the drive source for the sub-agitating blades 22, may be small. This sub-drive device 24
is integrally attached to the stirring shaft 10, rotates around the stirring shaft in conjunction with the rotation of the stirring shaft 10, moves up and down in conjunction with the raising and lowering of the stirring shaft 10, and also moves the sub-stirring shaft 20. It is moved up and down following the stirring shaft 10.

FIG. 3 shows a second embodiment of the apparatus of the present invention, in which the sub-agitating blades 22 are mounted substantially at right angles to the agitating blades 12. This allows horizontal stirring and vertical stirring to be performed simultaneously, resulting in better stirring and mixing. The configuration other than this is the same as that of the first embodiment.

FIGS. 4 and 5 show a third embodiment of the apparatus of the present invention, and unlike the first and second embodiments, a holder 26 is used instead of the connecting body 18 for stirring the stirring shaft 10 and the sub-stirring A shaft 20 is connected. The holder 26 has one end attached to the support column 4, and holds the stirring shaft 10 and the sub-stirring shaft 20 such that they can move up and down and rotate freely. For this reason, the first embodiment and the second embodiment
Unlike the embodiment, the sub-stirring shaft 20 does not rotate around the stirring shaft 10, and the sub-stirring shaft 20 rotates around the stirring shaft 1.
It is in a stationary positional relationship with 0 (see Figure 8). Also,
The driving source for the sub-agitating blades 22 is the driving device 6. That is, in the third embodiment, the stirring blades 12
The driving source for the and sub-agitating blades 22 is the same driving device 6. Note that the rotational speed is the same as in the first and second embodiments; the stirring blade 12 rotates at a low speed, and the auxiliary stirring blade 22 rotates at a low speed.
rotates at high speed. Therefore, since a small horsepower is required for both low speed and high speed, the drive device 6 does not need to be large. Further, the sub stirring blade 22 is attached substantially horizontally to the stirring blade 12 as in the first embodiment. The configuration other than this is the same as that of the first embodiment.

FIG. 6 shows a fourth embodiment of the apparatus of the present invention, in which the sub-agitation blades 22 are attached to be approximately perpendicular to the agitation blades 12. The configuration other than this is the same as that of the third embodiment.

In addition, in the above embodiment, the case where the sub-stirring blade 22 and the stirring blade 12 are parallel or at right angles is mentioned, but the invention is not limited to this, and the sub-stirring blade 22 may be arranged at an angle with respect to the stirring blade 12. Of course, you can do it.

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

The tracked self-propelled vehicle 2 is run and the entire device is installed at a position where a consolidation column for predetermined ground improvement is to be created.Then, the column 4 is supported approximately perpendicular to the ground, and the column 4 is a stirring shaft 10 that is supported so as to be able to rise and fall;
The stirring blade 12, the sub-stirring shaft 20, the sub-stirring blade 22, etc. are erected perpendicularly to the ground. Thereafter, the drive device 6 is driven to rotate the stirring shaft 10 and the like, and the rotating stirring blades 12 are lowered to the ground surface (FIG. 9A). Since the stirring blade 12 is equipped with a digging blade 16,
The ground is excavated as the stirring blades 12 rotate. At this time, in order to sink the stirring blades 12 into the ground while excavating the ground, the drive device 6 connected to the upper end of the stirring shaft 10 is lowered along the support. Since the stirring blade 12 also serves as an excavator, it is rotated at a low speed so as to obtain a predetermined excavating torque. By rotating at a low speed, the drive device 6 can be used even with a low horsepower, and the use of the drive device 6 with a low horsepower has the advantage of reducing the size and weight of the device 6 itself.

After the stirring blades 12 are immersed into the ground,
The soil stabilizer is poured into the excavated soil from the discharge port, and the excavated soil and the soil stabilizer are stirred and mixed by the stirring blades 12 submerged in the ground. When the stirring blade 12 is further recessed, the sub-stirring shaft 2 follows the descent of the stirring shaft 10.
0 also descends, and the sub stirring blade 22 located above the stirring blade 12 sinks into the ground. The sub-agitating blade 22 that has sunk into the ground is the same as the stirring blade 1 that has already sunk into the ground.
2 and mix the excavated soil and soil stabilizer with stirring (Figure 9B). At this time, since the stirring blades 12 rotate at a low speed, the stirring blades 12 may rotate with the excavated soil attached to them, and the stirring and mixing of the excavated soil and the soil stabilizer may not be achieved sufficiently. However, since the auxiliary stirring blade 22 that rotates at high speed is located above the stirring blade 12, even if the excavated soil adheres to the stirring blade 12, the auxiliary stirring blade 22 that rotates at high speed removes the excavated soil that has adhered to the stirring blade 12. Since the soil can be stirred, 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 small horsepower 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 carried out 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 stirring blades 12, etc. is finished. (Figure 9C). Then, in turn, the stirring blades 12 and the like are raised. At this time, the stirring blades 12 are rotated,
It may also be raised while being rotated in the opposite direction to the direction in which it is lowered (FIG. 9D). When raising, stirrer blade 1
Since drilling torque is not required for 2, stirring blade 1
2 can also be rotated at high speed. After such a process, the stirring blades 12 and the like are pulled out from the ground. In this case, the auxiliary stirring blade 22 follows the rise and fall of the stirring blade 12, rises, and is extracted from the ground. The work is completed by removing the stirring blades 12 etc. from the ground (Fig. 9E). Then, after the stirring blades 12 and the like are pulled out, a consolidation column is created.

[Effects of the Invention] As is clear from the above detailed description, according to the configuration of the present invention, the excavated soil and the soil stabilizer are mixed by stirring using a stirring blade that rotates at a low speed and a stirring blade placed above the stirring blade. This is achieved by the secondary stirring impeller, which rotates at high speed and is placed at a position where the center of rotation rotates around the stirring shaft at the same speed as the rotational speed of the stirring blade, so even if the excavated soil is rotated at a low speed, the stirring Even if it sticks to the blades, the sub-stirring blades that rotate at high speed and are placed above the stirring blades can reliably stir the excavated soil that has stuck to the stirring blades, and the agitation mix is good even for highly sticky soil. It can be done. In conjunction with this, in order to achieve the above effects, the stirring blade equipped with the digging blade rotates at a low speed, so it has a large torque, and the specified torque required for digging can be achieved without increasing the size of the drive device. can be obtained easily. 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 sub-stirring blades are 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. The size and weight of
Moreover, it is possible to create consolidation pillars for ground improvement in the ground while avoiding high costs.

In addition, since the rotation center of the sub-stirring blade is arranged at a position where it rotates around the stirring shaft at the same speed as the rotational speed of the stirring blade, and the sub-stirring blade rotates at high speed, the sub-stirring blade rotates around the stirring shaft at a high speed. Compared to a device that does not rotate around the area, that is, a device that rotates while remaining stationary at a specific position, it is possible to better stir and mix the excavated soil and the soil stabilizer, which is advantageous in practice.

[Brief explanation of drawings]

The drawings show an embodiment of the ground improvement method and its device according to the present invention, and FIG. 1 is an overall side view of the first embodiment, FIG. 2 is an enlarged view of the main parts of the first embodiment,
Fig. 3 is an enlarged view of the main parts of the second embodiment, and Fig. 4 is an enlarged view of the main parts of the second embodiment.
An overall side view of the embodiment, FIG. 5 is an enlarged view of the main parts of the third embodiment, FIG. 6 is an enlarged view of the main parts of the fourth embodiment, and FIG.
The figure is a cross-sectional view of the main part of the first embodiment, and Figure 8 is a cross-sectional view of the main part of the first embodiment.
FIG. 9, which is a cross-sectional view of the main part of the embodiment, is a diagram showing the order of work steps. In the figure, 2 is a self-propelled vehicle with track, 4 is a support, 6 is a drive device, 8 is a holding guide, 10 is a stirring shaft, 12
14 is a stirring blade, 14 is a discharge port, 16 is a digging blade, 18 is a connecting body, 20 is a sub-stirring shaft, 22 is a sub-stirring blade, 24
is an auxiliary drive device, and 26 is a holding body.

Claims (1)

[Scope of Claims] 1. The ground is excavated by rotating at low speed a stirring impeller equipped with a digging blade at the tip of a hollow cylindrical stirring shaft, and then a soil stabilizer is injected into the excavated soil, and then a soil stabilizer is poured into the excavated soil. A sub-mixer that rotates excavated soil and soil stabilizer at a high speed and is arranged at a position where the agitation blade and rotation center rotate at the same speed as the rotation speed of the agitation blade around the agitation shaft. A soil improvement method characterized by stirring and mixing with blades. 2. A stirring blade that rotates at a low speed and is equipped with a soil stabilizer discharge port and a digging blade is provided at the tip of a hollow cylindrical stirring shaft that is supported so as to be able to rise and fall freely, and a stirring blade that rotates at a low speed and that follows the rise and fall of the stirring blade and rotates. A ground improvement characterized in that an auxiliary stirring blade whose rotating center rotates around the stirring shaft at the same speed as the rotational speed of the stirring blade and which rotates at high speed is placed above the stirring blade. Device.