JPH0893382A - Earth-retaining wall and connection method thereof to tunnel - Google Patents

Abstract

PURPOSE: To improve safety and reduce construction period, by excavating the earth-retaining wall in the inside of a ring-form body with built-in FRC to expose the front end of a shield cylinder and joining the shield cylinder and the reinforcing material in the earth-retaining wall together and connecting it to the reached place of the wall to the tunnel. CONSTITUTION: An electric cable 5 covered with an insulating material is embedded in fiber- reinforced concrete in a conical ring body 2 and the conductivity between terminals from the surface side of the earth-retaining wall 1 is detected to check the excavation position. A shielding tunnel excavator 3 is driven toward the wall 1 to excavate the ground E and the shield cylinder 3a comes in contact with the ring body 2 while detecting the front position of the excavator 3 in the wall body. Then the rubber layer is cut to seal the clearance between the wall and the shield cylinder 3a. Water leakage from the front face of the excavator 3 is detected by opening a water-detection cock 6 installed in advance. In this case, when water is not perfectly cut off, a solidifying agent for cutting-off is injected in the ground E or the ring body 2 and after cutting-off, the surface of the wall is cut to expose the front face of excavator 3. Thereafter, the shield cylinder 3a is welded with the earth-retaining wall 1 and these are sealed with concrete and fixed together to connect the wall 1 and the tunnel 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel excavation method using a shield construction method when an excavator reaches a connection point with an existing tunnel, or a vertical shaft or an end hole at an intermediate point of tunnel construction. The present invention relates to improvement of a construction method for surely connecting an earth retaining wall body and a tunnel body provided at a reaching point.

[0002]

2. Description of the Related Art When excavating a tunnel by the shield construction method, it is necessary to provide a tunnel mouth in the earth retaining wall provided at the planned arrival point and connect it to the tunnel body. And when connecting the inner wall body and the earth retaining wall body that are provided as lining to protect the tunnel from earth pressure and spring water,
There was a risk that accidents such as inflow and outflow of sediment would occur.

Therefore, conventionally, as shown in FIG. 6, before the tip of the tunnel 4 reaches the earth retaining wall body 1, the solidification chemical liquid is injected into the ground E behind the earth retaining wall body 1 in advance so that the ground is formed. After the stabilization is performed, the stabilization zone G is excavated by the shield excavator 3 to reach the tunnel 4 to the back surface of the earth retaining wall body 1, and then the stabilization zone G and the lining 4a of the inner wall of the tunnel 4a. Water-stopping treatment was performed by filling a water-stopping material with the outer surface of the shield. After that, the earth retaining wall body 1 is cut from the surface side to form an opening having substantially the same diameter as that of the tunnel to expose the front surface of the excavator 3 so that the excavator 3 is retained.
After being penetrated inside, the devices inside the shield are disassembled and carried out, and the shield cylinder 3a and the earth retaining wall body 1 are joined by concrete or the like, and further the inner surface of the shield cylinder 3a is covered with an earth retaining wall. I was trying to complete the connection between the body 1 and the tunnel body 4.

[0004]

In such a conventional method, the ground behind the earth retaining wall must be stabilized over a wide range by a method such as chemical injection, so that the effect of ground stabilization must be confirmed. In addition to requiring a large amount of money, the prevention of accidents was not perfect. In addition, there is a problem that a large amount of chipping work is required to form the opening in the earth retaining wall, which requires a lot of labor and a long construction period.

Therefore, according to the present invention, when connecting the earth retaining wall body provided at the arrival point of tunnel excavation by the shield construction method and the tunnel body, it is possible to greatly reduce the amount of chiseling work for the earth retaining wall body. Therefore, it is an object of the present invention to provide an improved method of connecting an earth retaining wall and a tunnel reaching part, which can greatly improve the safety of work and can shorten the construction period and the construction cost.

[0006]

[Means for Solving the Problems] The above object is to fill at least the inside of a ring-shaped conical annular body with a fiber-reinforced concrete whose diameter increases toward the ground and whose minimum diameter is sufficiently smaller than the tunnel diameter. In the state of building the earth retaining wall body buried in the tunnel arrival scheduled position, and using a shield type tunnel excavator to excavate the tunnel to the tunnel arrival scheduled position of the earth retaining wall body of the conical annular body Arriving at least one part of the shield cylinder of the tunnel excavator to a position where it penetrates, exposing the earth retaining wall body from the surface side to expose at least the front end of the shield cylinder, and the shield cylinder And a step of connecting the conical annular body or the reinforcing material in the earth retaining wall body, which can be achieved by a method of connecting the earth retaining wall body and the tunnel reaching portion.

[0007]

In the earth retaining wall body constructed by the method of the present invention, a conical annulus whose diameter increases toward the ground and whose minimum diameter is sufficiently smaller than the tunnel diameter is embedded in advance at the tunnel arrival position. The conical annulus is filled with concrete reinforced with fibers instead of using reinforcing bars. Therefore, the shield tunnel excavator can penetrate the earth retaining wall while easily excavating the fiber-reinforced concrete portion of the earth retaining wall. And when the tip of the tunnel excavator penetrates at least a part of the conical annulus, the excavation is stopped,
When embedding a conductive wire for detecting the drilling tip position in the fiber reinforced concrete part, the tip position of the shield tube can be easily detected by the position of the cut conductive wire. Since the distance from the ring-shaped body can be easily known, it is possible to stop the excavation at an accurate position in the earth retaining wall.

Next, the earth retaining wall is excavated from the surface side to expose at least the front end of the shield cylinder, but a conical ring body through which the shield cylinder penetrates is formed from a laminated body of a steel layer and a rubber layer. At this time, the space between the earth retaining wall and the shield cylinder is sealed by the rubber layer, which prevents water leakage. Therefore, as a result of investigating the waterproof performance before excavation from the surface side of the earth retaining wall, even when it is necessary to inject a waterproofing agent, etc., from the surface of the earth retaining wall to the inside of the conical annulus desirably. By injecting the chemical liquid through the chemical liquid injection pipe provided so as to communicate with each other, it is possible to easily stop the water between the earth retaining wall body and the shield cylinder. After it is confirmed that there is no water leakage in this way, the earth retaining wall is excavated from the front side by, for example, manual work, but the excavation work is extremely efficient because the excavated part is fiber reinforced concrete and the amount of excavation is small. You can proceed.

In this way, after the front end of the shield cylinder is exposed from the opening of the earth retaining wall, the excavating devices and the like incorporated in the shield cylinder are detached and carried out, so that only the shield cylinder is removed. Left behind. Therefore, the shield cylinder is connected to the conical annulus in the earth retaining wall by welding or the like.However, when the earth retaining wall is reinforced with reinforcing bars except at the tunnel arrival position, the earth retaining wall is further strengthened. The connection between the earth retaining wall and the tunnel body is completed by welding the reinforcing bars of the body to secure the connection and then lining the connection with concrete or the like.

In carrying out the method of the present invention, the earth retaining wall may be, for example, a part of the wall surrounding an underground working space which is an intermediate point of tunnel excavation work, or at a wellhead such as a hillside. Even if it is built, it is possible to proceed with the work in exactly the same process.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention will be described below with reference to the drawings. 1 to 5, reference numeral 1 denotes, for example, an earth retaining wall body containing a reinforcing bar 1a surrounding a working space at the bottom of a vertical shaft provided at an intermediate point of a tunnel, and a conical annular body 2 is buried at a position where the tunnel is to reach. Has been done. Here, the conical annular body 2 is formed by laminating an outer steel plate 2a and an inner rubber layer 2b. Such a rubber layer 2b has a layered hard rubber portion 2bh and a layered soft rubber portion 2 in the example of FIG.
In the example shown in FIG. 5, the collar-shaped folds are formed of a hard rubber portion 2bh protruding inward and a foamed soft rubber portion 2bs provided between the folds. The structure of the rubber layer 2b is not particularly limited as long as it has a structure capable of closely adhering to the outer surface of the penetrating shield tube 3a.

If necessary, the conical ring body 2 may be provided with a chemical solution injection hole 2c. Such a chemical solution injection hole 2c
However, if it is formed by providing a synthetic resin injection pipe or the like with a synthetic resin plug fitted at the tip, the earth retaining wall body 1
It is more convenient because it will not be clogged with concrete or the like during the construction, and the synthetic resin pipe will be easily cut when reaching the tunnel, and the chemical injection hole 2c will open to the outer surface of the shield cylinder 3a.

Further, the smaller diameter of such a conical annular body 2 is sufficiently smaller than the diameter of the tunnel, and the larger diameter is an error of the arrival position of the tunnel, for example, about 20 cm vertically and horizontally from the planned arrival position. Considering that there is a possibility of deviation, it is preferable that the diameter is sufficiently larger than the diameter of the tunnel. Then, it is provided in the earth retaining wall body 1 in such a posture that the diameter is enlarged toward the ground E, that is, the tunnel going forward.

The conical annulus 2 is filled with fiber reinforced concrete which is reinforced by mixing, for example, stainless fiber 1b, and is filled with fiber reinforced concrete on the outside as necessary. Alternatively, the end of the large diameter portion of the conical annular body 2 or the like may be connected to the reinforcing bar 1a. In the fiber-reinforced concrete inside the conical annular body 2, the insulated coated electric wires 5, 5 ... Are spaced from the end having the larger diameter toward the end having the smaller diameter. Is embedded, and by detecting the continuity between the terminals pulled out from the surface side of the earth retaining wall body 1, it is possible to detect to what position the fiber reinforced concrete has been excavated. Further, the soil retaining wall body 1 is provided with a chemical solution injection pipe 7 opening on the surface side, and a part of the chemical solution injection tube 7 is connected to the chemical solution injection hole 2 c of the conical ring body 2.

When the shield tunnel excavator 3 advances toward the earth retaining wall 1 having such a structure,
Soil retaining wall 1 by excavating the ground E that has not been subjected to stabilization treatment
The tunnel excavator 3 reaches the back wall of the earth retaining wall 1.
Continue to enter the fiber reinforced concrete part of Then, while cutting the insulating covered electric wire 5, the front end position of the tunnel excavator 3 in the earth retaining wall body 1 is detected, and the excavation is carried out until the shield cylinder 3a comes into contact with the conical ring body 2. When the shield cylinder 3a comes into contact with the conical annulus 2, the soft rubber portion 2bs is first scraped off, and then the hard rubber layer 2b.
h is also scraped off, but at the same time, the shield layer 3 is formed by the rubber layer 2b.
Since the gap with a is sealed, inflow of water and earth and sand is prevented.

[0016] Here, the presence or absence of water leak from the front position of the tunnel excavator 3 is detected by opening the test tap 6 which is previously provided at the position where the earth retaining wall 1 is to reach the tunnel. If there is, the shield cylinder 3a is entirely conical with the conical annular body 2.
It is possible that the tunnel excavator 3 is further advanced so as to penetrate into the conical annulus 2. However, if the water still cannot be completely stopped, through the chemical solution injection pipe 7 etc. previously provided in the earth retaining wall 1,
Water can be stopped by injecting a solidification chemical for stopping water into the inside of the conical annular body 2 or the ground E.

After confirming that there is no water leakage from the faucet 6, the earth retaining wall 1 is shaved off from the surface side portion to expose the front surface of the tunnel excavator 3 to the open. After that, the excavating device and the like are disassembled from the inside of the shield tube 3a and carried out, and the shield tube 3a and the earth retaining wall body 1 are joined by welding and then fixed by a method such as sealing with concrete, The lining similar to the inner wall is applied to complete the connection between the earth retaining wall body 1 and the tunnel 4.

[0018]

According to the method of connecting the earth retaining wall body and the tunnel reaching portion of the present invention, the inside of the earth retaining wall body can be reached by the tunnel excavator without stabilizing the ground behind the earth retaining wall body. Since excavation can be carried out directly and water and sediment can be easily prevented, the work of removing the earth retaining wall from the surface side can be performed safely and easily, and the construction period can be shortened. . In addition to the fact that the ground stabilization agent is unnecessary, there is also an advantage that the construction cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a relationship between a structure of an earth retaining wall and a tunnel during excavation in a method of connecting an earth retaining wall and a tunnel reaching portion of the present invention.

FIG. 2 is an explanatory view showing a state in which the tunnel excavator has entered the earth retaining wall body in the method of the present invention.

FIG. 3 is an explanatory view showing a state in which the front surface of the tunnel excavator in the earth retaining wall body in the method of the present invention is exposed by scraping off the earth retaining wall body.

FIG. 4 is an explanatory diagram of a structure of an example of a conical ring body embedded in the earth retaining wall body in the method of the present invention.

FIG. 5 is an explanatory view of the structure of another example of the conical ring body embedded in the earth retaining wall body in the method of the present invention.

FIG. 6 is an explanatory diagram of a method of connecting a soil retaining wall body and a tunnel reaching portion according to a conventional technique.

[Explanation of symbols]

 1 Earth retaining wall 1a Reinforcing bar 1b Stainless fiber 2 Cone ring 2a Steel plate 2b Rubber layer 2bh Hard rubber part 2bs Soft rubber part 2c Chemical injection hole 3 Tunnel excavator 3a Shield cylinder 4 Tunnel 4a Cover 5 Insulation coated wire 6 Inspection Faucet 7 Chemical injection pipe E Ground G Stabilization zone

Claims (12)

[Claims] 1. A conical annulus whose diameter increases toward the ground and whose minimum diameter is sufficiently smaller than the diameter of the tunnel is embedded in the tunnel arrival position with at least fiber-reinforced concrete being filled inside the annulus. Step of constructing the earth retaining wall, and using a shield tunnel excavator to dig a tunnel to the tunnel reaching planned position of the earth retaining wall to a position where it penetrates at least a part of the conical annulus. A step of reaching a shield cylinder of the tunnel excavator; a step of excavating the earth retaining wall body from a surface side to expose at least a front end portion of the shield cylinder; the shield cylinder and the conical ring body or the soil. And a step of connecting a reinforcing material in the retaining wall body, the method for connecting the earth retaining wall body and the tunnel reaching portion. 2. The method for connecting an earth retaining wall and a tunnel reaching portion according to claim 1, wherein the conical annulus is formed of a laminated body of a steel layer and a rubber layer. 3. The rubber layer comprises a relatively hard rubber portion provided in contact with the inside of the steel layer and a relatively soft rubber portion formed inside the hard rubber portion. How to connect the earth retaining wall to the tunnel reaching part. 4. The method for connecting an earth retaining wall and a tunnel reaching portion according to claim 3, wherein the relatively hard rubber portion has an annular fold portion directed toward the center of the conical annular body. 5. The method for connecting the earth retaining wall and the tunnel reaching portion according to claim 3, wherein the relatively soft rubber portion is made of foam. 6. The method for connecting the earth retaining wall body and the tunnel reaching portion according to claim 1, wherein the earth retaining wall body is reinforced by reinforcing bars except at a tunnel arrival scheduled position. 7. The method for connecting the earth retaining wall and the tunnel reaching portion according to claim 1, wherein the earth retaining wall is a part of a wall surrounding the underground work space. 8. The earth retaining wall is constructed by embedding a conductive wire for detecting the position of the excavated tip of the tunnel in the fiber reinforced concrete filled inside the conical annulus. A method of connecting the earth retaining wall and the tunnel reaching part according to any one of 1. 9. The method of connecting the earth retaining wall body and the tunnel reaching portion according to claim 1, wherein the earth retaining wall body is provided with a chemical injection pipe. 10. The method for connecting the earth retaining wall body and the tunnel reaching portion according to claim 9, wherein the chemical solution injection pipe is provided so as to communicate with the inside of the conical annular body from the surface of the earth retaining wall body. 11. The method for connecting the earth retaining wall and the tunnel reaching portion according to claim 9 or 10, wherein the chemical liquid injection pipe is formed of a synthetic resin pipe. 12. The water stopping performance between the earth retaining wall and the shield cylinder is investigated prior to excavating the earth retaining wall from the surface side, and when the water stopping performance is insufficient, leakage stops. The method for connecting the earth retaining wall and the tunnel reaching part according to any one of claims 1 to 11, wherein the water blocking agent is injected up to.