JPH0227487B2 - JIBANKAIRYOHOHO - Google Patents

Description

Detailed Description of the Invention The present invention is a novel method for improving the solidification of soft ground by injecting a slurry solidifying agent into the soft ground, in which the ground mixing and stirring blades are operated not only horizontally but also vertically. It is about a proposal.

Conventionally, the stirring blades used to improve the ground by injecting a slurry solidifying agent into the ground and mixing it with the surrounding soil that makes up the ground are fixed to a rotating shaft, so they can only rotate horizontally. However, as shown in Figure 1, the stirring direction of the stirring blade is constant at any given depth (-h) when the rotating shaft is driven in or pulled out. (i.e., facing downward when driving in and facing upward when pulling out), not only is the stirring effect low, but soil such as silt, clay, and peat gradually adheres to the rotating shaft between the upper and lower stirring blades. This often results in a large lump-like shape that covers the upper and lower stirring blades, making it impossible to achieve any stirring effect at all.This results in various problems, such as the need for workers to scrape off the adhering soil with a shovel, etc. It was hot.

The present invention solves these problems and provides a method that enhances the stirring effect and prevents soil from adhering to the stirring blades and rotating shaft.

Fig. 3 shows an example of a device for carrying out the method of the present invention, in which 1 is a rotary tube which is rotated in the horizontal direction by a rotary drive prime mover 2 installed in the head, and an excavating blade 3 is fixedly attached to the lower end of the rotary tube. ing. Reference numeral 4 denotes two stirring blades arranged in the rotary tube 1 vertically at intervals and perpendicular to each other.
It penetrates through the inside of the tube 1, and its intermediate portion is pivotally supported by a horizontal shaft 6 provided within the tube 1, so that it can be turned up and down within the slit 5. Reference numeral 7 denotes actuating devices such as two hydraulic cylinders installed above the rotary tube 1, and the lower ends of the rods 8 are respectively connected to the stirring blades 4a and 4b. Due to the rotation of the cylinder 7 and the operation of the cylinder 7, horizontal rotation and vertical rotation are performed simultaneously.

FIG. 4 shows another device for carrying out the method of the present invention, in which the vertical rotation movement of the stirring blades 4 can be performed by the rotary drive motor 2 installed in the head without using the cylinder as described above. It is structured as follows. That is, a rotatable outer tube 9 is further provided on the outer periphery of the rotary tube 1, and the lower end of the outer tube 9 has an end opening 9a cut obliquely like the tip of a bamboo spear. 4a is pivoted in a close position such that its upper surface is always in contact with the outer tube end port 9a, and the lower stirring blade 4b is connected to the upper stirring blade 4a by a connecting arm 10 inserted into the rotary tube 1. It is configured to interlock with the upper stirring blade 4a. Further, as shown in FIG.
The rotary tube 1 is connected to the rotary tube 1 and is decelerated in the same direction (or in the opposite direction) as the rotary tube 1.

Therefore, at the same time as the rotary tube 1 rotates, the outer tube 9
Also rotates at a reduced speed, and the upper stirring blade 4a in contact with the outer tube end port 9a slides following the shape of the end port a, and as a result, a vertical rotational movement is generated at the same time as a horizontal rotational movement, and furthermore, the lower stirring blade 4b A similar movement is also performed in conjunction with the upper stirring blade 4a.

Next, the construction method using the apparatus shown in FIG. 4 will be explained. First, the rotary tube 1 and the outer tube 9 are rotated as described above by the prime mover 2, and the soft ground is excavated by the excavation blade 3 at the lower end. At the same time, a cement slurry solidifying agent is supplied from the supply pipe 13 into the rotary tube 1 and is discharged from the lower end spout 14. During this time, the upper and lower stirring blades 4
Since a and 4b are simultaneously rotated horizontally and rotated vertically as described above, the consolidation agent is effectively mixed and stirred with the surrounding soil. When the excavation blade 3 reaches a predetermined depth, the supply of the solidifying agent is stopped, the rotary tube 1 and the outer tube 9 are pulled out from the ground while rotating, and the solidifying agent is stirred again by the upper and lower stirring blades 4a and 4b. .

In the apparatus shown in Fig. 3, the same operation as above is carried out, but the vertical rotation movement of the stirring blades 4a, 4b by the actuating device 7 such as a cylinder is arbitrary depending on the properties of the surrounding soil, solidifying agent, etc. You may change it to

In the figure, the stirring blades 4 are provided in two stages, upper and lower, on the rotary tube 1, but they may be provided in just one stage or in three or more stages. Of course, this is a good thing.

In the present invention, as described above, the stirring blade not only performs the horizontal rotational movement by the rotary tube, but also simultaneously performs the vertical rotational movement.
As shown in the figure, even if we look only at the time of pulling out the rotary tube, the stirring direction of the stirring blade at any given depth (-h) is repeated upward stirring and downward stirring, and the driving or drawing speed and stirring blade By appropriately combining the amount of vertical movement of the blades, the stirring effect can be greatly increased, making it possible to create a pile body that is stronger than before. There is an advantage that the surrounding soil area is also effectively stirred at the same time. Furthermore, according to the present invention, since the stirring blades rotate horizontally and move vertically at the same time as described above, it is difficult for soil to adhere to them, and unlike conventional methods, the soil that adheres to the rotating pipe portion near the upper and lower stirring blades gradually becomes thicker. It has various advantages such as being able to maintain the above-mentioned stirring effect without becoming lumpy.

[Brief explanation of drawings]

Fig. 1 is a graph showing the displacement of the stirring blade over time in a conventional soil improvement device, Fig. 2 is a graph showing an example of the displacement of the stirring blade according to the method of the present invention, and Fig. 3 is a graph showing the displacement of the stirring blade according to the method of the present invention. FIG. 4 is an explanatory diagram showing another example of the apparatus, and FIG. 5 is a partially enlarged explanatory diagram of FIG. 4. Code explanation 1... Rotating tube, 2... Prime mover, 3...
Drilling blade, 4... Stirring blade, 5... Slit, 6...
Horizontal axis, 7... cylinder, 8... rod, 9...
...Outer tube, 10...Connection arm, 11...Drive shaft,
12... Gear, 13... Solidifying agent supply pipe, 14
... spout.

Claims (1)

[Scope of Claims] 1. A ground improvement method in which a slurry-like solidifying agent is injected into soft ground and mixed with surrounding soil using a stirring blade, in which the stirring blade is attached to a rotary tube so as to be able to rotate up and down, and the slurry-like solidifying agent is A ground improvement method characterized in that, when discharging binder, a stirring blade is simultaneously caused to perform horizontal rotation by a rotary tube and the above-mentioned vertical rotational movement to promote a stirring effect. 2. The ground improvement method according to claim 1, wherein the vertical rotation movement of the stirring blade is performed by connecting the lower end of a rod of a cylinder installed above the rotating tube to the stirring blade. 3. The vertical rotation movement of the stirring blades is achieved by providing a rotatable outer tube on the outer periphery of the rotary tube, connecting the outer tube to the drive shaft of the rotary tube via a gear, and decelerating the outer tube. The lower end has a diagonally cut end opening so that the upper surface of the stirring blade is always in contact with the end opening,
2. The ground improvement method according to claim 1, wherein said stirring blade slides in accordance with the shape of said end port as the stirring blade is horizontally rotated by a rotary tube. 4. The stirring blades are arranged in two or more stages, upper and lower, in the rotary tube, and the vertical rotational movement of the stirring blade in the uppermost stage is transmitted and interlocked to the stirring blades in the lower stage sequentially via a connecting arm. The ground improvement method described in paragraph 1, paragraph 2, or paragraph 3.