JP2002309892A - Cutoff method in pipe jacking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for maintaining the cutoff performance of a pit mouth in implementation of soil improvement in a small range, which is available in a urethane injecting method, by effectively injecting a urethane chemical solution on the periphery of the pit mouth from the interior of a shaft. SOLUTION: In implementation of the cutoff method at the time of drift- excavation by a pipe jacking method, when drift-excavation and starting is carried out from the interior of the shaft, an injection hole is bored in a substantial portion of a shaft wall toward the ground in a propelling direction from the interior of the starting shaft, and the urethane chemical solution containing two-part expandable urethane resins is mixed and fed into the injection hole, to thereby harden the ground before excavation. After the urethane chemical solution is injected to a back face of an area where an opening 17 is formed, urethane injection pipes 4 are inserted into the ground at locations that divide the circumference of the opening 17 into six sections, and therefore soil improvement is carried out in the vicinity of the opening 17 before excavation of the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water stopping method in a pipe propulsion method, and more particularly to a non-cutting pipe in which an excavation hole is formed by digging an underground from a shaft to the outside, and a pipeline is laid in the excavation hole. The present invention relates to a water stopping method for preventing inflow of mud or groundwater into a wellhead in a propulsion method.

[0002]

2. Description of the Related Art As a general water stopping method at the time of excavating a tunnel in a conventional non-cutting pipe propulsion method, a chemical liquid injection method for injecting a chemical liquid into a wellhead before the start of a pipe propulsion device is known. This chemical liquid injection method involves a problem that the injection of the chemical liquid is performed by penetrating the liquid injection rod from the ground into the ground where the water is stopped, so that the installation of the injection equipment is large and the unit price is high.

In the chemical liquid injection method, a predetermined improvement range may not be reliably improved due to a change in the state of penetration of the chemical liquid into the ground, and a relatively small diameter buried pipe is propelled as in the pipe propulsion method. In such a case, it cannot be said that the water stopping performance is sufficiently secured. For example, as shown in FIGS. 1 (a) and 1 (b), the consolidation portion is a pulse-shaped and partial consolidation as indicated by reference numeral 1 in a planned consolidation range 3 in which the ground is to be consolidated by injecting a chemical solution. Or uniform as shown by reference numeral 2.
May be consolidated. Therefore, even if a chemical solution is injected, the water stopping performance cannot be sufficiently ensured in the state shown in FIG. As described above, the chemical solution injection method requires a large amount of construction, requires a high construction unit price, and cannot secure sufficient water stopping performance depending on the state of penetration of the chemical solution.

[0004] In view of the above, there is a case where the injection machine is small and can be easily constructed in a vertical shaft, and the urethane injection method capable of suppressing the construction unit price is employed as a water stopping technology at the time of excavating and starting a tunnel by a pipe propulsion method. is there. This urethane injection method is
The purpose of the present invention is to significantly reduce the predetermined ground improvement range in the chemical liquid injection method and reduce the construction range. The urethane injection method is a void filling method and is used as an emergency measure for stabilizing the ground. The injection agent is urethane, which is a general urethane chemical containing isocyanate and polyol as main components.

However, in the conventional urethane injection method, as shown in FIG. 2, an injection hole 6 is formed by excavating the ground 7 from a shaft wall 5 of a shaft 25, and a urethane injection pipe 4 is formed in the injection hole 6. Is inserted to inject urethane, so that the urethane chemical flows into the shaft 25 as shown by reference numeral 8 in the gap 22 formed between the injection hole 6 and the injection pipe 7, and the urethane is injected into the ground 7. Did not penetrate sufficiently.

As a solution to this, there is a method called coking. As shown in FIG. 3 (a), as shown in FIG. 3 (a), an injection hole 6 is formed by excavating the ground 7 from a shaft wall 5 of a shaft 25, and a urethane injection pipe 4 is inserted into the injection hole 6 to inject urethane. In this case, a tube (caulking tube) 9 in which the two liquid urethane solutions are separated and sealed is used. The separation of the two liquids in the caulking tube 9 is released, and the contents are packed into the gap 22 while mixing.
As shown in (b), the caulking tube 9 is expanded by foaming at this position, and the caulking tube 10 is expanded.
In this way, the gap 22 on the shaft 25 side is closed.

[0007]

However, in this method, the caulking tube 9 is inserted into the gap 22 between the injection pipe 4 and the injection hole 6 as shown in FIG.
Since the caulking tube 9 is expanded to form the caulking tube 10 as shown in FIG. 1, a gap 13 is formed between the adjacent caulking tubes 10, so that the clogging tube cannot be expected to be reliably closed. There is a problem that it is impossible to cope with a minute gap where 9 does not enter.

In addition, when urethane is actually injected in the urethane injection method, a gap 22 is formed between the excavated urethane injection hole 6 and the injection pipe 4 as described above.
Further, since there is generally a gap between the ground 7 and the shaft wall 5, as shown in FIG. 5, the urethane chemical solution intensively escapes to a place having a small resistance (a part having a large gap). As a result, urethane may form a runaway portion 14 into a gap between the ground 7 and the shaft 5 in addition to the permeated portion 15 into the ground 7, and may not solidify in a predetermined range. In adopting the urethane injection method, there is also a problem that the problem of escape of urethane must be solved.

Further, in order to stop water using the urethane injection method, it is important to clarify the consolidation range with respect to the amount of urethane to be injected. It is necessary to prevent escape of the chemical. In particular, at the time of urethane injection, it is necessary to prevent the chemical solution from flowing out of the gap between the urethane injection hole 6 and the urethane injection pipe 4 to the shaft 25 side.

Therefore, the present invention solves the problems of the conventional urethane injection method, and as a method of stopping water at the pit of a shaft in a pipe propulsion method, a urethane injection method adopted instead of a chemical solution injection method. A pipe that can reduce the size of the pit and make it possible to work from the inside of the pit, and effectively inject a urethane chemical solution around the pit from the pit to secure the water stoppage of the pit by improving the ground in a small area. The purpose is to provide a water stopping method in the propulsion method.

[0011]

Means for Solving the Problems The water stopping method in the pipe propulsion method of the present invention for achieving the above object is a water stopping method for performing tunnel cutting by the pipe propulsion method, and excavates and starts a tunnel from inside a shaft. When performing the injection, an injection hole is formed on the ground in the propulsion direction from inside the starting shaft in the main part of the shaft shaft, and a urethane chemical solution consisting of two-part urethane resin is injected into this injection hole while mixing, and excavation is performed. It is characterized in that the ground to be solidified in advance is prevented from flowing mud or groundwater into the starting shaft during excavation.

In this case, before forming the injection hole, an injection hole for back injection is previously provided near a portion where a gap between the ground and the shaft wall is large, and a urethane chemical is injected into this injection hole for back injection in advance. The gap is closed by consolidating the gap, and then, an injection hole is formed in the ground to be consolidated, and a urethane chemical is injected into this injection hole,
The permeation state of the urethane liquid into the ground can be ensured.

The injection hole for back injection is formed below the center of the opening, and when the diameter of the opening is A (m), the center position of the injection hole for back injection is defined as The position may be 0.67 A (m) downward from the center of the part.

Further, after the position of the opening is determined, the injection hole is formed.
The injection hole may be formed at a plurality of locations equally divided along the circumference, and preferably, the injection hole may be formed at a position that divides the circumference of the opening into six equal parts.

Further, a nipple having a thread formed on the inner peripheral surface is attached to an injection hole formed by drilling a shaft wall and an injection hole for back injection, and the nipple is inserted until the injection pipe is inserted. Is sealed with a male screw, and threading is performed at the base of the injection pipe.When inserting the injection pipe horizontally from the vertical shaft into the injection hole, remove the male screw and remove the base of the injection pipe It is good to screw to the nipple.

According to the method for stopping water in the pipe propulsion method of the present invention, when stopping water at the entrance of a shaft in the pipe propulsion method,
Since urethane injection was performed instead of chemical injection, the construction equipment itself was reduced in size and work from the inside of the shaft became possible. Ground improvement can secure the water stoppage of the wellhead.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiment is merely an example, and it goes without saying that various changes or improvements can be made without departing from the spirit of the present invention. In the following description, FIG.
As for the same components as the conventional example described in FIG.
The description is given with the same reference numerals.

In the present invention, the injection of urethane is carried out from the inside of the shaft 25 by carrying a construction apparatus such as an injection machine into the shaft 25. First, back injection is performed as preliminary injection in order to surely perform injection for ground improvement. The back injection means that a urethane chemical is injected in advance into a large portion (a portion indicated by reference numeral 14 in FIG. 5) of the gap between the ground 7 and the shaft wall 5 and solidified to close the portion.

Therefore, the back injection is performed to reliably close the gap where the urethane liquid escapes around the injection hole for improving the ground. The escape speed of the urethane solution in back injection differs depending on the escape direction, and is vertically fastest and slowest. As shown in FIG. 6, when the diameter of the opening 17 is A (m), the installation position of the injection tube for back injection is 0.67 (m) below the center of the opening. The injection time was 133 A (se
c). In addition, when performing back injection, the injection speed is set to the maximum speed allowed by the injection machine so that the urethane liquid does not easily penetrate into the ground 7 and easily flows into a large portion of the gap between the ground 7 and the shaft wall 5. I do. If the back injection of the urethane chemical solution is performed by the above steps, the gap around the injection hole for ground improvement can be reliably pre-filled.

After the back injection is performed in this manner, a urethane chemical is injected into a place where it is desired to solidify. The ground improvement range to secure the water stopping function by urethane chemical is as follows: the diameter is twice the diameter of the opening, and the depth of the opening is 50c.
m column. On the other hand, as shown in FIG. 7, the ground improvement body made of urethane chemical solution has a diameter of 500 to 500 μm per injection pipe.
It becomes a columnar body having a length of about 600 mm and a length of about 970 to 1650 mm.

Accordingly, in the present invention, the opening 17 of the shaft shaft wall is provided.
The injection pipe installation position is determined so that the installation position of the urethane injection pipe is evenly arranged on the circumference of the opening 17 at the site where the is to be installed. For example, in this embodiment, FIG.
As shown in (5), six injection pipes 4 are arranged at equal intervals along the outer circumference of a predetermined circle of the opening. With this arrangement, when the diameter of the opening is A (mm), the interval between adjacent injection pipes 4 is 0.5 A (mm). As shown by the broken line and the two-dot chain line in FIG. 8, the ground improvement with a diameter of 600 mm can be performed on one injection pipe 4, so that it is surely a cylindrical shape having a diameter of twice the opening diameter and a depth of 50 cm. A ground improvement area can be formed.

When the consolidation of the urethane chemical is completed, the shaft can be opened at the site where the opening 17 of the shaft is to be installed in the same manner as during normal start.

Further, when water is stopped using the urethane injection method, it is important to clarify the consolidation range with respect to the urethane injection amount. It is necessary to prevent the escape of the urethane chemical.
In particular, it is necessary to prevent the urethane chemical from flowing out of the gap between the urethane injection hole 6 and the urethane injection pipe 4 toward the shaft 25 when urethane is injected.

Therefore, in the present invention, in order to prevent the urethane chemical from flowing out of the gap between the urethane injection pipe 4 and the urethane injection hole 6, as shown in FIG.
Then, as shown in FIG. 9B, a female nipple 19 is attached to the urethane injection hole 6 by welding. The nipple 19 has a threaded inner peripheral portion. Then, until the urethane injection pipe 4 is inserted, the male screw 20 is screwed to the nipple 19 as a lid to stop water from leaking from the nipple 19 such as underground water.

On the other hand, a male threaded portion 21 is formed at the root of the urethane injection tube 4. Then, when inserting the urethane injection pipe 4 into the urethane injection hole 6, after removing the male screw 20 from the nipple 19, the urethane injection pipe 4 is inserted into the urethane injection hole 6, and the threaded portion 21 at the root portion is removed. Screw it to the nipple 19. As a result, a higher water stopping effect than that of the conventional caulking can be obtained, and a minute gap can be closed.

[0026]

As described above, according to the present invention,
At the time of stopping water at the entrance of the shaft in the pipe propulsion method, it is possible to stop water from the inside of the shaft by a small construction device, and it is possible to prevent the urethane chemical solution from running away by following the injection method according to the present invention. It is possible to reliably solidify the ground in a predetermined range by the injection amount. As a result, a reliable water stopping effect can be expected as compared with the conventional chemical injection method, and the ground improvement range can be significantly reduced.
There is an effect that the construction cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 shows the state of permeation of a chemical in a conventional chemical injection method, in which FIG. 1 (a) shows a state in which a liquid permeating a planned consolidation area is pulsed and partially consolidated, and FIG. It is a figure which shows the state which the chemical | medical solution which permeated the consolidation area | region was uniformly and integrally consolidated.

FIG. 2 is a view showing a state in which a urethane chemical flows into a gap formed between an injection hole and an injection pipe in a conventional chemical injection method.

FIG. 3 is a view showing a current caulking procedure in the urethane injection method, in which (a) is a view showing a state before expansion of a caulking tube, and (b) is a view showing a state of an expansion day of the coking tube.

FIG. 4 is a view for explaining a problem in coking; FIG. 4 (a) is a view showing a state of a gap between an injection hole into which a caulking tube is inserted and an injection pipe, and FIG. It is a figure which shows the state after the expansion of the inserted caulking tube.

FIG. 5 is a diagram showing a permeation state of a chemical solution in a urethane injection method.

FIG. 6 is a view showing an installation position of an injection tube in back injection.

FIG. 7 is a view showing a solidified state per one injection tube.

FIG. 8 is a view showing an installation position of an injection pipe with respect to an opening in the present invention.

FIG. 9 is an explanatory view showing a method of closing a gap in place of caulking, in which (a) shows a state in which a urethane injection hole is formed in a vertical shaft wall, and (b) shows a state in which a nipple is attached to the urethane injection hole. Figure showing how to stop the water by screwing a male screw to the
(c) is a diagram showing a state in which a urethane injection tube having a threaded portion formed at the base is inserted into the urethane injection hole.

[Explanation of symbols]

 Reference Signs List 4 urethane injection pipe 5 shaft wall 6 urethane injection hole 7 ground 9,10 caulking tube 13 gap 14 urethane runaway part (back injection part) 16 urethane injection hole 17 opening 18 solidified part 19 nipple 20 male screw 21 threaded part 22 gap 25 shaft

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidenori Hino 2-3-1 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Masashi Miyatake 2-3-3, Otemachi, Chiyoda-ku, Tokyo No. 1 Nippon Telegraph and Telephone Corporation F-term (reference) 2D054 AC18 EA07 FA02

Claims (6)

[Claims] The present invention relates to a method of stopping water when excavating a tunnel by a pipe propulsion method. An injection hole (6) is formed in the ground (7) in the propulsion direction from inside
(6) Mixing and injecting a urethane chemical solution consisting of a two-part foamed urethane resin into the ground, and solidifying the ground (7) to be excavated beforehand Water stopping method in pipe propulsion method characterized by preventing inflow of groundwater. 2. Prior to forming the injection hole (6), an injection hole (16) for back injection is previously formed on the ground (7) and the shaft wall (5).
Closed by providing a urethane chemical in advance into the injection hole (16) for back injection and solidifying the gap, and then closing the ground ( 7), the injection hole (6) is formed, and the urethane chemical is injected into the injection hole (6) to ensure that the urethane chemical permeates the ground (7). The method for stopping water in a pipe propulsion method according to claim 1. 3. The back injection hole (16) has an opening.
When the opening (17) is formed below the center of (17) and the diameter of the opening (17) is A (m), the center position of the injection hole (16) for back injection is defined by the opening (17). 0.67A downward from the center of
3. The method for stopping water in a pipe propulsion method according to claim 2, wherein the position is set to (m). 4. The method according to claim 2, wherein the injection hole is formed at a plurality of positions equally divided along the circumference after the position of the opening is determined. The method for stopping water in the described pipe propulsion method. 5. The method for stopping water in a pipe propulsion method according to claim 4, wherein the injection hole (6) is formed at a position where the circumference of the opening (17) is equally divided into six. 6. The injection hole (6) formed by drilling the shaft wall (5) and the injection hole (16) for back injection, a nipple (19) having a thread formed on the inner peripheral surface. ) Attach the injection tube
Until the insertion of (4), the nipple (19) is sealed with a male screw (20), and a thread is cut at the base of the injection pipe (4). When inserting in the direction from the shaft wall (5) into the injection hole (6, 16), after removing the male screw (20), screw the root of the injection pipe (4) to the nipple (19). The method for stopping water in a pipe propulsion method according to claim 1, wherein the method is stopped.