JPH0430489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a ground stabilization method for stabilizing the ground by draining groundwater through a pipe inserted into the ground.

(Problem to be solved by the invention) Stabilizing the ground through land preparation on sloped land and other naturally unstable ground is a major social issue, but there has been no suitable solution to date, and heavy rains occur. Disasters such as cliff collapses and landslides occur every time, and it is strongly desired to find a method to stabilize them.

Recently, as a solution to this problem, reinforcing bars are inserted into the holes formed by boring into the ground, and mortar is injected into the holes to strengthen the ground. Methods have been proposed and developed, such as inserting the bag into the bag and inflating the bag to expect a compaction effect.

However, all of these means aimed at reinforcing or strengthening the ground are merely stabilization methods that primarily utilize the tensile force of members inserted during drilling.

In reality, ground failure is often caused by the phenomenon of groundwater permeating into the ground, such as a decrease in the strength of the ground due to the infiltration of groundwater, an increase in water pressure due to a rise in the groundwater level, and an increase in pore water pressure during an earthquake. It can be said that groundwater is the main cause of ground collapses after heavy rains, such as soil liquefaction.

The previously proposed method of injecting mortar during drilling and integrating it with the ground reduces the water permeability of the ground and increases water pressure on the back side, while inserting a tube fitted with a bag. This method only involves solidifying and strengthening the ground, but does not take into account groundwater drainage treatment. In addition, because the drainage method involves inserting a drainage pipe into a borehole, and the drainage pipe and the ground are not integrated, groundwater flows through the gap between the drainage pipe and the borehole wall, washing away surrounding earth and loosening the ground. There is a fear.

As described above, the conventional methods involve performing either ground strengthening or drainage separately, and do not solve the fundamental problem of making ground strengthening and drainage possible at the same time.

This invention was made based on the above circumstances,
The main purpose is to drain underground water, and by providing this function to a pipe inserted into the ground, it simultaneously strengthens the ground and drains water, thereby solving the problem of stabilizing unstable ground. Means for Solving Problems) In the present invention, by inserting a pipe body provided with a large number of water permeability holes on the outer peripheral wall surface into the ground, groundwater is drained from one end of the pipe body through the water permeation mouths to the drainage located on the ground surface. At the same time as draining water to the mouth, the bag attached to the pipe is expanded with a consolidating material to fix the pipe to the ground.
The surrounding ground will be consolidated and pore water will penetrate into the water holes, strengthening and stabilizing the ground.

Groundwater, as well as pore water generated by soil consolidation, permeates into the water inlet by capillary action and is easily drained through the pipe body.

The pipe body is fixed to the ground by the expansion of the bag attached to its outer periphery, but it is also fixed to the ground by a tension member inserted and fixed inside this bag, or by the injection material injection provided on its outer periphery. By injecting the injection material into the ground from the entrance, it is fixed to the ground and supplements the effect of strengthening the ground.

(Example) The present invention will be described below with reference to drawings showing one example.

First, the first invention will be explained based on FIGS. 1 to 4.

In this invention, a tube body A having a bag body 2 and a water permeation port 3 provided on an outer circumferential wall surface 1 is inserted into a borehole B formed in the ground, and the tube body A is expanded by expanding the bag body 2 into the borehole B. The hole wall B-1 is fixed to the hole wall B-1, and the underground water is
This method improves drainage and stabilizes the ground.

The bag body 2 and the water permeable port 3 are provided at arbitrary positions on the tube body A at arbitrary intervals.

The bag body 2 is made of a flexible material, and a solidifying material 4 is injected into the bag body 2 and expanded to fix the tube body A to the hole wall B-1. A rubber sleeve 5a is attached to an injection port 5 through which the caking material 4 is injected to prevent the caking material 4 from flowing back. The cementing material 4 is injected by inserting the injection tube 6 into the tube body A. Since the consolidation material 4 is injected into the bag body 2, it does not flow into the outer periphery of the water permeable port 3 or into the tube body A, and the drainage effect is not inhibited.

A large number of water holes 3 are provided between the bags 2, 2, as shown in FIGS. 1 and 2, for example, and the positions and manner of providing the water holes 3 are determined depending on the nature of the ground. That is, the pipe body A is provided so that the water permeation port 3 is located in the ground where water is stagnant, the spring layer, the layer where underground water flows, etc. FIG. 2 shows an example of earth retaining.

The tube body A is inserted deeply into the ground and is fixed by the inflated bag body 2. The base end of the pipe body A is located on a slope secured by a retaining wall 7 and becomes a drainage port 8. In this case, groundwater and pore water permeate into the pipe body A from the water permeation port 3 and are drained from the drain port 8 through the pipe body A. This eliminates the accumulation of groundwater and reduces pore water pressure, thereby preventing a decrease in ground strength and collapse of the ground due to water pressure in the backing soil.

Plastic, glass fiber reinforced resin, steel pipe, etc. are used for the tube body A, and in the present invention, the tube body A is integrated with the ground by injecting the consolidation material 4 into the bag body 2.
Since the tensile strength of pipe A is imparted to the ground, pipe A
The effect of ground reinforcement increases as materials with higher tensile strength are used. Therefore, it is extremely effective to apply the present invention to unstable ground such as landslide areas.

Note that when steel is used, it is more effective to improve its durability by subjecting it to anti-corrosion treatment such as plating with bad lead, and reinforced concrete pipes can also be used. Furthermore, especially for the purpose of preventing clogging of the water inlet 3, the outer periphery of the pipe body A around the water inlet 3 may be covered with a nonwoven fabric or the like.

FIG. 3 shows an embodiment in an embankment. In places near such rivers, the pore water pressure increases due to earthquake vibrations and the ground becomes liquefied, but according to the present invention, groundwater flows in through the water permeation port 3 provided below the groundwater table and rises, so the pore water pressure decreases. The rise and liquefaction of the soil can be suppressed, the embankment can be maintained in a stable state, and the tensile strength of the tube body A can also be imparted to the ground to strengthen the ground. This method is particularly useful for protecting buildings built on fine sandy ground with high groundwater levels from damage during earthquakes.

Figure 4 shows the case where the groundwater is applied to the ground of a tunnel. In this case as well, groundwater is drained from the permeation port 3 to the drainage port 8, so the ground can be stabilized and the water can be removed from the ground surface. Water leakage can be prevented, and the pipe body A provides a reinforcing effect, which makes it extremely easy to earthen the surface.

This invention is also effective for drainage in ground consolidated by injection or the like.

When the ground is consolidated, the strength of the ground increases, but water permeability decreases, which can cause water pressure to build up behind the ground, creating a risk of landslides. In these cases,
Boring is carried out through the consolidated area to the back, and a drainage pipe is inserted to lower the groundwater level at the back, but the groundwater at the back infiltrates into the consolidated area through the gap between the drain pipe and the boring wall, and gradually consolidates. Erodes or loosens the area, reducing the consolidation effect.

In the above case, the water inlet 3 of the pipe body A according to the present invention
If the bag body 2 is located at the back of the consolidation area and the bag body 2 is located within the consolidation area, groundwater at the back of the consolidation area will not infiltrate into the consolidation area due to expansion of the bag body 2. will disappear. This makes it possible to protect the consolidated area, lower the groundwater level, and stabilize the ground.

Next, the second invention will be explained with reference to FIG.

This invention is a construction method for reinforcing the tube body A of the first invention with the tensile material 9. In other words, pipe body A is called bag body 2.
At the same time, the tensile material 9 is inserted into the pipe body A and fixed thereto to increase the tensile resistance of the pipe body A and drain underground water.

The tensile member 9 has its tip fixed to the tip of the tube body A as shown in FIG. 5, and its base end fixed to the ground surface.
It increases the tensile resistance of the tube body A and resists the earth pressure acting on the retaining wall 7 etc. on the ground surface.

After fixing the tube body A to the ground, the tension member 9
It is inserted into the tube body A and is screwed onto the tip end of the tube body A as shown in FIG. 5, or fixed by filling with mortar. After the tension member 9 is fixed, it may be tensioned.

Next, the third invention will be explained with reference to FIG.

In addition to fixing the pipe body A to the ground and draining ground water using the bag body 2 of the first invention, this invention also injects the injection material 11 into the ground from the injection material injection port 10 provided on the outer peripheral wall surface 1 of the pipe body A. This is a construction method that strengthens the fixation of tube body A.

The injection material injection port 10 is provided on the outer circumferential wall surface 1 of the tube body A at an appropriate position between the bag body 2 and the water penetration port 3 in the same manner as the water penetration port 3 and the water penetration port 5, and the injection material 11 is connected to the consolidation material 4. Similarly, it is injected into the ground through the injection pipe 6. The injection material 11 penetrates into the ground and integrates the pipe body A with the ground, thereby supplementing the fixation by the bag body 2.

The injection material 11 is injected into the ground after the consolidation material 4 is injected into the bag body 2, that is, after the tube body A is fixed to the ground. Therefore, the injection material 11 rarely flows to the position of the water permeation port 3 due to the Packer effect caused by the expansion of the bag body 2, but if there is a possibility of this, the injection material 11 between the injection material injection port 10 and the water permeation port 3 is Inflow can be prevented by increasing the installation distance of the bag body 2.

In the explanation of the first, second, and third inventions above, an example was described in which a hole is drilled in the ground and the pipe body A is inserted, but the present invention not only stabilizes the ground itself, but also stabilizes the embankment. It is also applicable when That is, during embankment, the earth is laid while the pipe body A of the present invention is laid, and after the filling, the bag body 2 is expanded to separate the soil and the pipe body A.
It is possible to drain and strengthen the embankment at the same time.

(Effects of the Invention) As described above, the present invention drains groundwater in the ground through the pipe and at the same time strengthens the ground with the pipe, so even unstable ground can be effectively stabilized. In other words, by eliminating groundwater, the main cause of ground instability will be eliminated.

[Brief explanation of drawings]

1 to 4 show an embodiment of the first invention, FIG. 1 is a partial sectional view of a pipe, and FIGS. 2 to 4 are schematic diagrams showing construction examples. . FIG. 5 is a partial sectional view showing the tube body of the second invention,
FIG. 6 is also a partially sectional view showing the tube of the third invention. A: Pipe body, B: Hole drilling, B-1: Hole wall, 1: Outer peripheral wall surface, 2: Bag body, 3: Water permeation port, 4: Consolidation material, 5:
Inlet, 5a: Rubber sleeve, 6: Injection tube, 7:
Retaining wall, 8: Drainage port, 9: Tensile material, 10: Injection material injection port, 11: Injection material.

Claims (1)

[Scope of Claims] 1. After inserting into the ground a pipe body with a flexible bag body attached to the outer circumferential wall surface and a water permeable hole provided in at least a portion thereof, a consolidation material is injected into the bag body, A ground stabilization method characterized by inflating the bag body, fixing the pipe body to the surrounding ground, and draining groundwater from the water permeation port through the pipe body to the pipe body drainage port located on the ground surface. 2. After inserting into the ground a tube with a flexible bag attached to the outer peripheral wall and at least a portion of which has a water permeable port, a consolidating material is injected into the bag to inflate the bag. A ground characterized by fixing a pipe body to the surrounding ground, inserting a tensile material into the pipe body and fixing it to the pipe body, and draining groundwater from a water permeation port through the pipe body to a pipe body drainage port located on the ground surface. Stable construction method. 3. After inserting into the ground a pipe body with a flexible bag body attached to the outer peripheral wall and at least a part of which is provided with a water permeation port and an injection material injection port, and then injecting a consolidating material into the bag body, and The injection material is injected into the ground through the injection material injection port, the bag body is inflated, and at the same time the injection material is diffused to fix the pipe body to the surrounding ground, and groundwater is passed through the pipe body from the water permeation port to the ground surface. A ground stabilization method characterized by draining water to a body drainage outlet.