JPH0533332A - Ground improvement method - Google Patents

Abstract

PURPOSE:To prevent flooding of spring water and soil during processes from drilling to erection of a double-pipe in a ground improvement work wherein the double-pipe and a double-packer are employed by attaching a seal box to a mouth of the drilled hole for the ground to be improved. CONSTITUTION:A seal box 1 is attached, through a shutter plate 10, to a specified position on the ground to which improvement is executed, and easing 2 is inserted to where core drilling is made beforehand. Then the casing 2 is inserted with a cock 8 shut and with a cock 9 open, and after the easing reaches a specified depth as it is guided by the drilling with a bit 12 provided at its front end, muddy water produced during the drilling is drained through the cock 9. The cock 9 is shut and an external tube 3a is inserted into the easing for setting up there. Then the easing 2 is put in counter rotation and is extracted with its front end bit 12 unlocked. A gate valve 5 is then closed, applying sealing around the external pipe 3a, and sealing 30 is provided in the mouth of the drilled hole 29 by injecting water-stopping agent through an injection port 8. In final stage of execution, seal-grouting is applied throughout the drilled hole 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement method which is useful for injecting a chemical solution into a ground to be improved by applying a sleeve injection means, and particularly when applied to construction under pressurized water.

[0002]

2. Description of the Prior Art The sleeve injection method is a method for injecting a chemical solution by using a double pipe and a double packer to improve the ground, and already has many construction results. When applying such a sleeve pouring method to construction under pressured water, it is necessary to take measures to prevent the outflow of spring water and earth and sand generated from the mouth between drilling and double pipe installation.

Conventionally, various measures have been taken as measures for preventing the outflow of spring water and earth and sand, but there are advantages and disadvantages in that the construction is complicated or troubles are easily caused during the construction.

The present invention has been made for the purpose of eliminating such conventional problems.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to a gate valve, a mouth seal box having an inlet and an outlet, a casing having a tip bit that can be appropriately separated by remote control, and a sleeve for injection. ，
A method of improving the ground by using an outer pipe, and a. The step of attaching the above-mentioned seal box to the mouth of the improvement target ground, and the casing from the insertion port of the above-mentioned box attached to the mouth of the ground. While drilling in the ground through the gate valve in the open state, by the drilling guide by the tip bit and the drilling water guide ejected from the nozzle with the stop valve opening at the tip of the bit. In addition, mud water containing pressurized water generated during drilling works is caused to flow backwards on the outside of the casing and is discharged to the outside through the outlet of the above box, and penetrates to a specified depth, at a specified depth within the ground. Inserting and installing the outer tube for sleeve injection into the casing that has penetrated to the upper end, while leaving the outer tube in the insertion installation position and disconnecting the tip bit from the casing by remote control, The process of extracting the casing along the outer pipe to the position outside the gate valve inside the box while sealing the outer pipe with the seal member attached to the box. (5) Closing the gate valve with the casing kept in the extraction position. The process of sealing around the outer pipe in the box by operation, while keeping the seal around the outer pipe by the gate valve, press-in and fill the waterproofing agent from the injection port of the seal box, The process of applying a seal to the ground, the process of press-fitting and filling the entire inside of the hole with the seal grout through the outer pipe after the seal at the mouth of the drilling hole, J The present invention relates to a ground improvement method characterized by including steps and.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to the accompanying drawings.

To carry out the method of the present invention, a mouth seal box 1, a casing 2, and a double pipe as a sleeve injection device, that is, an outer pipe 3a and an inner pipe 3b are used.

The mouth seal box 1 is for inserting and guiding the casing 2 into the ground in a state where the mouth is sealed as shown in FIG. 1, for example, and a mouth seal for sealing around the casing 2 on the inlet side of the casing 2. A portion 4 is provided inside, a gate valve 5 is opened and closed from the side, an inlet 6 is provided inside the valve 5, and an outlet 7 is provided outside the valve 5, and the inlet 6 and the outlet are provided. The opening and closing cocks 8 and 9 are provided in the unit 7, respectively.

The casing 2 is provided with a tip bit 12 for excavating the ground at the tip, and the bit 12 is provided with an injection port 14 with a check valve 13 as shown in FIG.

It is necessary that the tip bit 12 provided at the tip of the casing 2 can be appropriately separated from the casing 2 by remote control.

In the embodiment shown in FIG. 9, the tip bit 12 is removably inserted into the shaft hole 2a of the casing 2 at the hollow shaft portion 12a, and in this inserted state. The casing 2 is configured so that it can be locked or unlocked by rotating the casing 2 forward or backward at a predetermined angle.

In order to configure the lock mechanism, as shown in FIG. 9, on the outer peripheral surface of the hollow shaft portion 12a of the tip bit 12,
An arcuate shape, for example, an anti-rotation projection 15 having an angular width of 60 ° is formed at two positions with the axis center interposed therebetween. A locking projection 16 having a predetermined angle width, for example, an angle width of 15 ° is provided on a front end surface 15a of each detent projection 15 in the excavation rotation direction. The angular widths of the uniform projections 15 and the projections 16 are shown in detail in FIG.

On the other hand, on the shaft hole 2a side at the tip of the casing 2,
An angle width slightly exceeding the sum of the angular widths of the projection 15 and the projection 16, for example, an angle width of 90 °.
7 are formed at two positions with the center of the shaft in between, and the projection 15 and the projection 16 are fitted into the concave groove 17 at the time of insertion. Front end surface 17a of the groove 17 in the excavation rotation direction
A locking projection 18 that locks with the locking projection 16 is formed so as to open at the bottom. Although the locking recess 18 is formed over the entire length between the recessed grooves 17 in FIG. 9, it may have at least an angular width corresponding to the locking projection 16.

FIG. 10 shows the locked state, in which the locking projection 16 is engaged in the locking recess 18 and is prevented from coming off. Further, the front end surface 15a of the detent projection 15 in the excavation rotation direction abuts on the front end surface 17a of the concave groove 17 in the same direction, whereby the casing 2 and the tip bit 12 rotate integrally, and the ground can be excavated. In addition, as shown in FIG.
In the locked state, the rear end surface 15b of the anti-rotation protrusion 15
And the rear end surface 17b of the concave groove 17 between the locking projection 1
There is a spacing 19 of angular width, for example 30 °, which exceeds the angular width of 6.

In FIG. 10, when the casing 2 is rotated in the direction opposite to the excavation rotation direction indicated by the arrow 20, if the casing 15 is rotated,
The rotation of 30 disengages the locking projection 16 from the locking recess 18 and unlocks it, so that the tip bit 12 can be separated.

As shown in FIG. 7, an annular seal member 21 is mounted on the inner peripheral surface of the casing 2 near the tip, and the inner diameter of the member 21 is substantially equal to or larger than the outer diameter of the outer tube 3a. It is slightly smaller, and if it is smaller, it is composed of an elastic member such as rubber.

The outer tube 3a, which constitutes one of the parts of the sleeve injection device, has an injection port 22 and the port 2 as shown in FIG.
A plurality of injecting portions 24, each of which is composed of an expandable and contractible sleeve 23 that covers the outside of 2, are provided at a plurality of positions at appropriate intervals in the axial direction. On the other hand, the inner tube 3b has a double packer portion 27 at its tip as shown in FIG. 6, and a strainer portion (not shown) is formed between the packers.

In carrying out the method of the present invention, as shown in FIG. 1, first, the seal box 1 is attached at a predetermined position on the ground surface to be improved via the shutter plate 10, and then the casing 2 is attached to the mouth of the box 1. The core boring mark 11 formed in advance on the ground surface is inserted through the seal portion 4 and the gate valve 5 in the open state.

Next, while the cock 8 is closed and the cock 9 is open, a rotation imparting device (not shown) is operated to rotate the tip bit 12 in the direction in which the tip bit 12 rotates integrally with the casing 2, and the casing 2 is placed in the ground. As it is inserted, the casing 2 drills the ground by the drilling guide by the tip bit 12 and the drilling water drilling guide ejected from the tip injection port 14 (see FIG. 7). The drilling is continued until the predetermined depth is reached while adding the casing 2.
Spouting of spring water from the inside of the casing 2 which may occur when the casing 2 is replenished is prevented by the check valve 13 provided in the jet port 14.

The situation during the drilling operation is shown in FIG. 2, in which the mud water containing the pressurized water and drilling water generated during the drilling operation flows backward intensively outside the casing 2 and the gate valve in the open state. 5, and is discharged to the outside from the discharge port 7 outside thereof through the cock 9 in the open state.

After the drilling operation by the casing 2 is completed, the cock 9 of the discharge port 7 is closed and the casing 2
The outer tube 3a of the sleeve injection device is inserted and installed therein. Further, the casing 2 is rotated in the reverse rotation direction by, for example, 15 to 30.
The tip bit 12 is rotated by this reverse rotation
The lock of the casing 2 is released, and the casing 2 can be pulled out.

Therefore, in this state, as shown in FIG. 3, the jack 32 is operated to pull out the casing 2. At this time, the lower end of the casing 2 passes through the gate valve 5 (see FIG. 4). ) Ends. During the pulling-out operation of the casing 2, muddy water flowing between the casing 2 and the outer pipe 3a slides on the outer peripheral surface of the outer pipe 3a while being attached to the casing 2 (see FIG. 8). Is prevented by. Further, during the same operation, appropriate pressing means is applied to the outer pipe 3a so that the outer pipe 3a does not accompany the withdrawal of the casing 2.

After the casing 2 is pulled out to a predetermined position, the gate valve 5 is closed to seal around the outer pipe 3a as shown in FIG. A seal 30 is applied to the mouth of the drilled hole 29.
As the water blocking agent, any water blocking agent may be used, and for example, cement milk, water glass and the like are suitable. Since the seal around the outer pipe 3a by closing the gate valve 5 and the seal 30 at the base of the drilling hole can sufficiently counteract the water pressure of the water to be pressurized, for example, the seal box 1 and the upper member 1 including the discharge port 7
When the two-part configuration of A and the lower member 1B including the gate valve 5 is adopted, the lower member 1B including the gate valve 5 can be left and the others can be removed.

After the sealing of the drill hole mouth portion is completed, the inner tube 3b is inserted into the outer tube 3a as shown in FIG. 5, and the seal grout 33 is inserted into the hole 29 through the inner and outer tubes 3a and 3b. Press-fitting is performed under a pressure exceeding the pressure of the water to be compressed.

After the curing and solidification of the grout agent 33 to be filled in the hole is completed, the inner tube 3 is again placed in the outer tube 3a as shown in FIG.
After inserting b, cracking and water pushing are carried out in the usual manner to inject and fill the ground with the grout agent, and then all the work of ground improvement is completed.

After the ground improvement operation is finished, the inner pipe 3a, the lower member 1B and the shutter plate 11 are recovered and buried in the outer pipe 3b and the tip bit.

Although the ground improvement in the vertical direction has been described in the embodiment, the same effect can be obtained by applying the ground improvement in the horizontal direction.

[0028]

[Effect] According to the method of the present invention, by applying the gate valve, the measure against water leakage from the spring during the process from drilling to the outer pipe installation is perfect, and before the seal grout is filled into the drilling hole. Since the casing can be pulled out in the process, the work of pulling out the casing is facilitated, and the risk of breaking the seal grout layer by the pulling out of the casing is eliminated, and a high quality seal grout layer can be formed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a situation at the start of drilling in a method of the present invention.

FIG. 2 is a vertical cross-sectional view showing a situation at the end of the drilling.

FIG. 3 is a vertical cross-sectional view showing a situation when the casing is pulled out.

FIG. 4 is a vertical cross-sectional view showing a situation at the time of sealing the mouth.

FIG. 5 is a vertical cross-sectional view showing a state when the seal grout is filled into the drilled hole.

FIG. 6 is a vertical sectional view showing the states of the cracking and water pushing steps.

FIG. 7 is an enlarged cross-sectional view of a tip bit portion provided in the casing.

FIG. 8 is an enlarged cross-sectional view showing how the casing is pulled out.

FIG. 9 is a perspective view showing details of a lock mechanism of a tip bit.

10 is a cross-sectional view taken along line 10-10 of FIG.

FIG. 11 is a partial vertical sectional view of an outer tube.

[Explanation of symbols]

 1 mouth seal box 2 casing 3a outer pipe 3b inner pipe 4 mouth seal part 5 gate valve 6 discharge port 7 injection port 8 cock 9 cock 12 tip bit 13 check valve 14 injection port

Claims (1)

Claims: 1. A gate valve, a mouth seal box having an inlet and an outlet, respectively, a casing having a tip bit that can be appropriately separated by remote control, and inner and outer tubes for sleeve injection. A method of performing ground improvement using ,, and a. The step of attaching the above-mentioned seal box to the mouth of the improvement target ground, and opening the inside of the box from the insertion port of the above-mentioned box attached to the mouth of the ground. While drilling in the ground through the gate valve in the state, by the drilling guide by the tip bit and the drilling water drilling guide ejected from the nozzle with the stop valve opening at the tip of the bit, The muddy water containing the pressurized water generated during drilling work flows back to the outside of the casing and is discharged to the outside through the discharge port of the above box while penetrating to a predetermined depth. , A step of inserting and installing an outer tube for sleeve injection into a casing that has penetrated to a predetermined depth in the ground, d. The process of extracting the casing along the outer pipe to the position outside the gate valve inside the box while sealing the outer pipe with the sealing member attached to the casing. The process of sealing around the outer pipe in the box by operation, while keeping the seal around the outer pipe by the gate valve, press-in and fill the waterproofing agent from the injection port of the seal box, The process of applying a seal to the hole, the process of press-fitting and filling the entire inside of the hole with the seal grout through the outer pipe following the seal at the base of the hole The ground improvement method is characterized by including the step of injecting a chemical solution into the ground through the inner and outer pipes as usual.