JP7273507B2 - Shield method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a shield construction method capable of lowering the water pressure of groundwater in the face portion.

There is known a method of lowering the groundwater level of natural ground around a lining (segment) to prevent the lining from rising (see Patent Document 1).
In this method, a tail void, which is a gap between the inner peripheral surface of a tunnel cavity excavated by a shield machine and formed behind the shield machine and the outer peripheral surface of the lining, is filled with grout holes (injection holes). After filling with mortar or other backfill material, a drainage device is installed at the mouth of the grout hole, and a drilling machine is used to drill the backfill material filled in the tail void to form a through hole that reaches the ground. Then, a water pipe is inserted into this through-hole to drain groundwater from the natural ground around the lining. In this method, the through holes are filled with a material to stop water.

Japanese Patent No. 5282541

However, in the conventional technology described above, since a series of operations of assembling the lining, filling the tail void with the backfill material, excavating the shield machine, and draining the water is repeated, the tunnel cavity portion is repetitive each time the shield machine advances. However, it is difficult to lower the water pressure of the groundwater in the face part.
The present invention provides a shield construction method capable of lowering the water pressure of the groundwater in the ground of the face portion below the standard when the water pressure of the groundwater in the ground of the face portion is higher than the standard.

In the shield construction method according to the present invention, an annular lining body formed of a plurality of lining members arranged along the inner peripheral surface of the tail portion of the outer shell of the shield machine that excavates the natural ground is provided by the shield machine. In the shield construction method, which is installed in the tunnel cavity formed behind the shield machine as it excavates, it is checked whether the water pressure of the groundwater in the ground at the face part is higher than the standard. Judging by whether the earth pressure value measured by the earth pressure gauge installed on the inner bulkhead is higher than the standard design earth pressure value, if the water pressure of the groundwater in the face part is below the standard, Backfill material filling work to fill the gap between the outer peripheral surface of the annular lining and the natural ground each time the annular lining is installed in the tunnel cavity as the shield tunneling machine advances. If the water pressure of the groundwater in the ground at the face portion is higher than the standard, a plurality of ring-shaped linings are installed in the tunnel cavity as the shield machine advances, and the inner surface of these ring-shaped linings By using a plurality of through-holes penetrating through the outer surface and the outer surface, draining work was performed to drain the groundwater of the ground inside the plurality of annular lining bodies, so that the groundwater in the ground of the face part was drained. When the water pressure falls below the standard, the backing material filling work is performed to fill the gap between the outer peripheral surface of the plurality of annular lining bodies and the ground with the backing material. When the water pressure of the groundwater in the ground of the face portion is higher than the standard, the water pressure of the groundwater in the ground of the face portion can be lowered below the standard. Therefore, even if the water pressure of the groundwater in the ground at the face portion is higher than the standard, the construction of the shield tunnel can be carried out smoothly.
In addition, since work to prevent the plurality of annular linings installed in the tunnel cavity from lifting was carried out and water was removed, the plurality of annular linings could be prevented from floating, and the plurality of the plurality of annular linings Since the amount of deviation between the designed installation position and the actual installation position can be reduced, the shield tunnel can be constructed with high accuracy.
In addition, for the work to prevent the ring-shaped lining from floating up, among the through-holes passing through the inner surface and the outer surface of the plurality of ring-shaped linings, the through-holes other than the through-hole used for draining the water are covered with the ring-shaped lining. An advance/retreat member provided so as to be able to advance and retreat between a state in which it protrudes outward from the outer peripheral surface of the body and a state in which the tip is positioned in the through hole is mounted, and the tip of the advance/retreat member is pushed from the outer peripheral surface of the annular covering body. Since the plurality of annular lining bodies are supported by the natural ground by protruding outward and abutting against the natural ground, the floating of the plurality of annular lining bodies can be reliably prevented.
In addition, the draining work is performed by attaching to the through hole a check valve open maintenance means for keeping the check valve installed in the through hole in an open state. After removing from the through-hole, the device for filling the backing material is connected to the through-hole, so that the draining work can be performed smoothly, and the transition from the draining work to the work for filling the backing material can be easily performed. Tunnel construction can be done smoothly.

Process drawing explaining section division by a shield construction method. Sectional drawing which shows the shield machine used for the shield construction method. Sectional drawing which shows the through-hole formed in the segment. FIG. 4 is a cross-sectional view showing a state in which a check valve is attached to the through-hole of the segment; FIG. 4 is an exploded perspective view showing a support device attached to a through hole; Sectional drawing which shows the state by which the cylindrical member was attached to the through-hole. Sectional drawing which shows the state by which the support apparatus was attached to the through-hole. FIG. 4 is an exploded perspective view showing a drain device attached to the through hole; FIG. 4 is a cross-sectional view showing a state in which a check valve opening member is attached to an injection hole; FIG. 4 is a cross-sectional view showing a state in which a check valve opening member and a relay member are attached to an injection hole; FIG. 4 is a cross-sectional view showing a state in which a check valve opening member, a relay member, and a pressing member are attached to an injection hole; FIG. 4 is a cross-sectional view showing a state in which a check valve opening maintaining means is attached to an injection hole to form a drain device; The perspective view which shows the example of arrangement|positioning of a support apparatus and a drainage apparatus with respect to a tunnel lining. (a) is a perspective view of a threaded pipe member, (b) is a longitudinal section of the threaded pipe member (Embodiment 2).

Embodiment 1
In the shield construction method according to the first embodiment, it is determined whether or not the water pressure of the groundwater in the ground in the face portion is higher than the standard, and when it is determined that the water pressure of the groundwater in the ground in the face portion is below the standard will perform normal shield construction (hereinafter referred to as normal construction), and if it is determined that the water pressure of groundwater in the natural ground in the face part is higher than the standard, shield construction (hereinafter referred to as specified construction work).

As shown in FIG. 1, when it is determined that the water pressure of the groundwater in the ground in the face portion is higher than the standard, in the specific construction performed in the segment ring installation section Y (see FIG. 1(c)), the face portion over the inner peripheral surface and outer peripheral surface of the segment rings 30, 30 ... as a plurality of annular lining bodies installed in the tunnel cavity when it is determined that the water pressure of the groundwater in the ground is higher than the standard Drainage work is performed to drain groundwater from the natural ground to the inner side of the plurality of segment rings 30, 30 through the penetrating through-holes.
As a result of the water removal work, when it is determined that the water pressure of the natural ground in the face portion has fallen below the standard, the outer peripheral surfaces of the plurality of segment rings 30, 30 ... installed in the segment ring installation section Y and The shield tunnel in the segment ring installation section Y is completed by performing a back-filling material filling operation for filling the tail void, which is a gap between the ground and the ground, with the back-filling material.

In the shield construction method according to the first embodiment, as shown in FIG. In the segment ring installation section X when it is determined that the water pressure of is below the standard, normal construction is performed and the tunnel formed behind the shield machine 1 by excavating the ground with the shield machine 1 Suppose that several to several tens of segment rings 30 are installed in the cavity.
After that, for example, when the discharge gate 10e of the screw conveyor 10 (to be described later) of the shield machine 1 is opened, an outburst occurs, and it is determined that the water pressure of the groundwater in the ground at the face portion is higher than the standard.
In this case, as shown in FIG. 1(c), after the segment ring installation section X, the segment ring installation section Y is the period until it is determined that the water pressure of the natural ground in the face portion has decreased to a level below the reference level. A plurality of segment rings 30, 30, .
As a result of the water removal work, when it is determined that the water pressure of the ground in the face portion has fallen below the standard, the outer peripheral surfaces of the plurality of segment rings 30, 30, . . . The tail void, which is the gap between and, is filled with a backing material to complete the shield tunnel in the segment ring installation section Y.
After that, when it is determined that the water pressure of the groundwater in the ground at the face portion is below the standard, as shown in FIG. In the segment ring installation section X after construction of the segment ring installation section Y, which is to be constructed, normal construction is performed.

That is, in the shield construction method according to the first embodiment, in the segment ring installation section X, which was constructed when it was determined that the water pressure of the groundwater in the ground in the face portion was below the standard, the shield tunneling machine 1 formed along with the excavation of the segment ring. Immediately after the segment ring 30 is installed in the hollow part of the tunnel, the segment ring is installed by performing normal construction to fill the tail void, which is the gap between the outer peripheral surface of the segment ring 30 and the ground, with a backfill material such as mortar. Complete the shield tunnel in Section X.
In the segment ring installation section Y, which was constructed when it was determined that the water pressure of the groundwater in the ground at the face portion was higher than the standard, the segment ring 30 was installed in the tunnel cavity formed as the shield machine 1 advanced. immediately after the segment ring 30 is installed, the tail void, which is the gap between the outer peripheral surface of the segment ring 30 and the natural ground, is not filled with the back-filling material, and is formed as the shield machine 1 advances. Drainage work is carried out by passing groundwater from the natural ground to the inner side of the plurality of segment rings 30, 30 through through holes formed in the plurality of segment rings 30, 30, . . .
As a result of the draining work, when it is determined that the water pressure of the natural ground in the face portion has decreased to a level below the standard, the outer peripheral surfaces of the plurality of segment rings 30, 30 ... installed in the segment ring installation section Y Backfill material filling work is performed to fill the tail void, which is the gap between the ground and the ground, with the backfill material. That is, the shield tunnel in the segment ring installation section Y is completed by filling the backfill material in order from the segment ring 30 on the rear side (start shaft 100 side) in the segment ring installation section Y.

Next, a configuration example of the shield machine 1 used in the shield construction method according to the first embodiment will be described.
As shown in FIG. 2 , the shield machine 1 has a cutter head 2 at the front end in the excavation direction, and an outer shell 3 behind the cutter head 2 . A partition wall 4 is provided on the front side of the outer shell 3 , and a chamber 5 is provided between the partition wall 4 and the cutter head 2 .
Devices such as an erector 6 , a shield jack 7 , a folding jack 8 , a cutter head driving device 9 , a screw conveyor 10 and the like are provided inside the outer shell 3 .

The cutter head 2 is, for example, a disk-shaped member for excavating a face, and excavating members such as a plurality of bits 2a are attached to the front surface of the cutter head 2 . The cutter head 2 is rotatable in forward and reverse directions along the circumferential direction of the outer shell 3 in front of the outer shell 3 .

The outer shell (skin plate) 3 includes, for example, a front body plate 3a and a rear body plate 3b connected to the rear end side of the front body plate 3a.
The front body plate 3a and the rear body plate 3b are formed of, for example, cylindrical steel plates.
The inner side of the rear body plate 3b is constituted by a tail portion 11 equipped with an erector 6, a tail seal 3c and the like.
The tail seal 3c is a sealing member for preventing groundwater or the like from entering the outer shell 3 from the ground behind the rear plate 3b during excavation work. is installed in a frame shape along the outer periphery of the rear body plate 3b.

The chamber 5 is a space filled with excavated soil between the cutter head 2 and the partition wall 4 .
That is, the shield excavator 1 excavates the earth and sand excavated by the cutter head 2 and takes it into the chamber 5 through an opening (not shown) of the cutter head 2, filling the chamber 5 with mud. This is a mud pressure shield tunneling machine that generates mud pressure and performs excavation work in a state where the mud pressure is opposed to the earth pressure of the face.

The erector 6 is a device that holds a segment (segment piece) 20 as a covering member, turns, arranges a plurality of segments 20 along the inner peripheral surface of the tail portion 11, and assembles the segment ring 30. is.

The segment 20 is a lining member made of, for example, reinforced concrete that covers the inner peripheral surface of the tunnel cavity formed as the shield machine 1 advances.
A plurality of segments 20 , 20 . . . forming one segment ring 30 are conveyed to the tail portion 11 , and the segment ring 30 is assembled within the tail portion 11 by the erector 6 .
That is, the segment ring 30 is configured by combining a plurality of segments 20 formed in the shape of circular arc blocks forming the annular peripheral wall of the segment ring 30 .

A through hole 23 with an internal thread 25 penetrating through the inner surface 21 and the outer surface 22 of the segment 20 is formed approximately in the center of the arcuate plate surface of each segment 20, 20, as shown in FIG. It is

The shield jack 7 propels the shield machine 1 forward by using the segment ring 30 assembled in the tail part 11 and the segment ring 30 installed in the tunnel cavity behind the shield machine 1 as a reaction force receiver. It is a jack that generates force.
A plurality of shield jacks 7 are arranged side by side along the circumferential direction of the outer shell 3 at positions straddling the boundary between the front body plate 3 a and the rear body plate 3 b within the outer shell 3 .

The folding jack 8 is a jack for connecting the front body plate 3a and the rear body plate 3b and for correcting the direction in which the shield machine 1 is driven. A plurality of folding jacks 8 are arranged side by side along the circumferential direction of the outer shell 3 at positions straddling the boundary between the front body plate 3a and the rear body plate 3b inside the outer shell 3 .
By supplying pressurized oil to the folding jack 8 and propelling the shield machine 1 in a state in which the front body plate 3a and the rear body plate 3b are bent in a predetermined direction and angle, the shield machine 1 is operated. It is possible to control the direction of propulsion of

The cutter head driving device 9 is a motor (driving source) that rotates the cutter head 2 forward and backward. A plurality of cutter head driving devices 9 are arranged side by side along the circumferential direction of the cutter head 2 on the back side of the cutter head 2, for example.

The screw conveyor 10 is a device for discharging earth and sand taken into the chamber 5 to the rear of the shield machine 1 .
The screw conveyor 10 is a closed-type conveyor that conveys earth and sand by means of a screw auger 10b arranged inside the cylinder 10a. A sand discharge port 10d provided at the other end of the cylinder 10a is provided so as to be positioned behind the shield machine 1. As shown in FIG. The earth and sand discharge port 10d is provided with a discharge gate 10e for opening and closing the earth and sand discharge port 10d.
The excavated earth and sand taken into the chamber 5 is conveyed from the earth and sand intake opening 10c to the earth and sand discharge port 10d by the screw auger 10b, and the excavated earth and sand is discharged from the earth and sand discharge port 10d by opening the discharge gate 10e. , a belt conveyor, a carriage, etc. (not shown) are used to transport them into the starting pit 100 and discharge them onto the ground.

The normal construction work using the shield machine 1 described above when it is determined that the water pressure of the groundwater in the ground at the face portion is below the standard is performed as follows.
A plurality of segments 20 are arranged along the inner peripheral surface of the tail portion 11 of the outer shell 3 of the shield machine 1 by the erector 6 of the shield machine 1, The segment ring 30 is assembled by connecting the ends of the adjacent segments 20, 20 using connecting tools.
The rear ends of the pistons of a plurality of shield jacks 7, 7, . The thrust reaction force obtained by extending the pistons of the shield jacks 7, 7, . The shield excavator 1 is excavated by excavating the face with the shield machine. After excavating the shield machine 1, the tail void, which is the gap between the outer peripheral surface of the segment ring 30 installed in the tunnel cavity formed behind the shield machine 1 and the natural ground, is filled with a backfill material. Then, the lining by the segment ring 30 is completed.
Then, the pistons of the shield jacks 7, 7, . The end portion and the front end portion of the previously assembled segment ring are connected using a connector.
That is, in the normal construction, by repeating a series of operations of assembling the segment ring 30 at the tail portion 11, excavating the shield machine 1, and filling the tail void with the back-filling material, the back of the shield machine 1 is constructed. A cylindrical tunnel cover formed by a plurality of segment rings 30, 30, ... which are installed along the inner peripheral surface of the tunnel cavity and are connected to each other so as to be adjacent to each other in the front-rear direction. A body is formed.

When starting the shield machine 1 from the starting shaft 100, a reaction force receiver (not shown) for the shield jacks 7, 7, . . . , 7 . . . are pushed against the reaction force receiver, and the thrust reaction force obtained by extending the pistons of the shield jacks 7 , 7 . The shield excavator 1 is started by driving the cutter head 2 to excavate the face.

In the specific construction when it is determined that the water pressure of the groundwater in the ground at the face portion is higher than the standard, a series of operations of assembling the segment ring 30→water countermeasures→excavation is repeatedly performed.
The water countermeasure work includes the lifting prevention work of the segment ring 30 installed in the tunnel cavity and the work of draining water into the segment ring 30 installed in the tunnel cavity.

Then, when it is determined that the ground water pressure in the face portion has fallen below the standard due to the specific construction work, the plurality of segment rings 30, 30 installed in the segment ring installation section Y during the specific construction work. Backfilling work is carried out to fill the tail void, which is the gap between the outer peripheral surface of … and the ground, with the backfilling material, and then the normal construction is started.

I will explain the water countermeasure work.
First, the supporting device 50 used for lifting prevention work and the draining device 60 used for draining work will be described.

As shown in FIG. 3, a through-hole 23 with a female thread is formed in the substantially central portion of the arcuate plate surface of each segment 20, 20, and extends through the inner surface 21 and the outer surface 22 of the segment 20. ing.
The through hole 23 has a configuration in which a female threaded portion 25 is provided on the inner peripheral surface of a through hole 24 penetrating through the inner surface 21 and the outer surface 22 of the segment 20 . Female screw portion 25 is provided on the center side in the direction along the center line of through hole 24 . Specifically, the internal thread portion 25 is, for example, a trapezoidal thread.
In the following description, the female threaded portion 25 and the threaded portion other than the female threaded portion screwed into the female threaded portion 25 are triangular threads, for example.
The female threaded portion 25 extends from one end opening 26a of the hollow tube 26 to the center of the hollow tube 26 on the inner peripheral surface of the hollow tube 26 made of casting embedded in the inner peripheral surface side of the through hole 24 of the segment 20, for example. It is formed by an internal thread 25 extending over the sides.
The outer peripheral surface of the hollow tube 26 is provided with an annular fixing portion 27 protruding from the periphery of the outer peripheral surface of the hollow tube 26 in order to secure fixing of the segment 20 to the concrete.

For example, one end of the hollow tube 26 is fixed to reinforcing bars arranged in a formwork (not shown) for manufacturing the segment 20, and one end of the hollow tube 26 is fixed to form the hollow portion of the through hole 24. After placing the unillustrated core that closes the opening 26a and the unillustrated core that closes the other end opening 26b of the hollow tube 26, fresh concrete is placed in the formwork, and then the concrete hardens. After that, by extracting the core, a through hole 23 with a female screw portion 25 penetrating through the inner surface 21 and the outer surface 22 of the segment 20 as shown in FIG. A formed segment 20 is fabricated.

By attaching a check valve 40 to the female threaded portion 25 of the through hole 23, an injection hole 28 is formed as shown in FIG.

The check valve 40 includes, for example, a cylindrical portion 41 and a valve portion 42 provided inside the cylindrical portion 41 .
The outer peripheral surface of the cylindrical portion 41 is provided with a male threaded portion 43 that is screwed into the female threaded portion 25 of the through hole 23 . The male threaded portion 43 functions as a portion for attaching the through hole 23 to the female threaded portion 25 .
The valve portion 42 includes a valve body portion 44 and a valve seat 45 .
The valve body portion 44 includes a valve body 46 and a valve body support portion 47 .
For example, the valve body portion 44 is configured by a circular body having a diameter corresponding to the inner diameter of the cylindrical portion 41 .
A valve body support portion 47 is a central portion of the circular body that connects opposite points on both ends of the diameter of the inner peripheral circle of the cylindrical portion 41 (positions separated from each other by 180 degrees along the circumferential direction on the inner peripheral surface of the cylindrical portion 41). , and the respective semicircular plate portions provided on the left and right sides of the valve body support portion 47 constitute the valve bodies 46 , 46 . That is, the central portion of the circular body constituting the valve body support portion 47 extends, for example, along a diametrical line passing through the center of the circular body, and both extended ends extend to both ends of the diameter of the inner peripheral circle of the cylindrical portion 41 . It is composed of a plate-shaped body with a rectangular cross section fixed to the opposite point of .
A straight line portion that serves as a boundary between the valve body support portion 47 and the valve bodies 46, 46, that is, each semicircle of the circular body that forms the valve body support portion 47 and the disc body that forms the valve bodies 46, 46 The hinges 48, 48, which are the centers of rotation of the valve bodies 46, 46, are formed with chord portions, which are boundaries with the shaped plate portions.
The valve seat 45 has a surface in contact with a surface on the side closer to the inner surface 21 of the segment 20 at the arc edges 49 of the valve bodies 46, 46 in the closed state of the flow path, i. It is formed by an annular wall projecting towards the centerline.

The check valve 40 is attached to the through-hole 23 by screwing the male-threaded portion 43 of the cylindrical portion 41 into the female-threaded portion 25 of the through-hole 23 , and the valve bodies 46 , 46 rotate toward the outer surface 22 of the segment 20 . As a result, the inside of the cylindrical portion 41 becomes a channel open state in which it communicates as a channel. That is, the space between the valve body supporting portion 47 and the valve seat 45 becomes the flow path. In this valve open state, an object can flow from the inner surface 21 side to the outer surface 22 side of the segment 20 via the flow path. Also, the flow path closed state in which the surfaces of the arc edges 49, 49 of the valve bodies 46, 46 on the side closer to the inner surface 21 of the segment 20 contact the valve seat 45, and the flow path inside the cylindrical portion 41 is closed. , the flow of objects from the outer surface 22 side to the inner surface 21 side of the segment 20 is closed.
In other words, the check valve 40 is configured to allow movement of an object from the inner surface 21 side of the segment 20 toward the outer surface 22 side and not permit movement of the object from the outer surface 22 side of the segment 20 toward the inner surface 21 side. It has become.
That is, when the backfill material is injected from the inner surface 21 side of the segment 20 to the outer surface 22 side of the segment 20 through the injection hole 28, the surface of the arc edge portion 49 of the valve body 46 near the inner surface 21 of the segment 20 is filled. is separated from the valve seat 45, and the inner side of the cylindrical portion 41 is opened to communicate as a flow path, so that the tail void can be filled with the backfill material.
In addition, the valve bodies 46, 46 and the valve seat 45 come into contact with each other due to the pressure of fluid such as backfill material and groundwater flowing into the injection hole 28 from the outer surface 22 side of the segment 20, and the flow path inside the cylindrical portion 41 is closed. Closed.

For example, the check valve 40 is not attached to the through hole 23 of the segment 20 which is to be positioned above the segment ring 30 assembled with the tail portion 11, and the supporting device as shown in FIG. 50 is attached.
In addition, in the injection hole 28 configured by attaching the check valve 40 to the through hole 23 of the segment 20, a check valve open valve as shown in FIG. A maintenance means 60A is attached.

As shown in FIG. 5, the supporting device 50 used for the lifting prevention work of the segment ring 30 installed in the tunnel cavity is, for example, an advancing/retreating member provided with a male screw portion 51 formed on the entire outer peripheral surface. It is composed of a threaded member 52 and a cylindrical member 53 that guides the advance and retreat of the threaded member 52 .
The cylindrical member 53 has a male threaded portion 54 formed on the outer peripheral surface on the one end opening 53a side in the direction along the center line and screwed into the female threaded portion 25 of the through hole 23, and is formed on the entire inner peripheral surface. It has a female threaded portion 55 to which the male threaded portion 51 of the threaded member 52 is screwed.
First, as shown in FIG. 6, the cylindrical member 53 is attached to the through hole 23 by screwing the male threaded portion 54 of the cylindrical member 53 into the female threaded portion 25 of the through hole 23 and fastening and fixing. The cylindrical member 53 is attached to the through hole 23 so that the other end opening 53b is positioned on the outer surface 22 side of the segment 20. As shown in FIG.
Then, as shown in FIG. 7, by screwing the male threaded portion 51 of the threaded member 52 into the female threaded portion 55 of the cylindrical member 53, the tip 52t of the threaded member 52 protrudes outward from the outer surface 22 of the segment 20. A support device 50 is provided so as to be able to advance and retreat between a state in which it is placed and a state in which it is positioned within the through hole 23 .
One end face 52a of the screw member 52 is provided with a jig engaging portion 52b for engaging a jig such as a nut driver or a screwdriver to rotate the screw member 52 around the center line.

As shown in FIG. 8, the drain device 60 used for draining groundwater from the ground into the segment ring 30 installed in the tunnel cavity is, for example, the above-described reverse valve attached to the through hole 23 . A stop valve 40 and a check valve open maintenance means 60A for keeping the check valve 40 in an open state so that groundwater in the natural ground passes through the check valve 40 and is drained inside the segment ring 30. .
That is, the check valve 40 is closed when the valve bodies 46 , 46 and the valve seat 45 come into contact with each other due to the pressure of fluids such as backfill material and groundwater that flow into the injection hole 28 from the outer surface 22 side of the segment 20 . In order to drain groundwater from the outer surface 22 side of the segment 20 to the inner surface 21 side of the segment 20 via the flow path of the check valve 40, It is necessary to maintain the left and right valve bodies 46, 46 of the check valve 40 in an open state. Therefore, in the drain device 60, the check valve 40 is maintained in an open state by using the check valve open maintenance means 60A, so that groundwater from the natural ground flows through the check valve 40 from the outer surface 22 side of the segment 20. It is constructed such that water is passed through the channel to the inside of the segment ring 30 .

As shown in FIG. 8, the check valve opening maintaining means 60A includes a check valve opening member 61, a relay member 62, a pressing member 63 that presses the check valve opening member 61, and a check valve with a water outlet. a retaining member 64;

As shown in FIGS. 8 and 9, the check valve opening member 61 has left and right claws that are inserted into the injection hole 28 from the inner surface 21 side of the segment 20 and push open the left and right valve bodies 46 , 46 of the check valve 40 . A bifurcated tip portion 66 having portions 65 , 65 and a shaft portion 67 extending rearward from left and right central portions 66 e at the rear end of the bifurcated tip portion 66 .

The bifurcated distal end portion 66 is formed in a plate shape, and as shown in FIG. formed in
The left and right claw portions 65, 65 have end edge surfaces 68, 68 facing each other forming a V-shaped surface, and the lower end portion of the V-shaped surface, which is the boundary portion between the left and right claw portions 65, 65, is reversed. It is formed in a concave groove portion 69 into which the valve body support portion 47 of the stop valve 40 is inserted.
In addition, the bifurcated tip portion 66 is formed in such a shape that a portion of a pentagonal plate material such as a home plate is notched. For example, a triangular area for forming a V-shaped surface is notched from one side edge of a pentagon such as a home base that forms an angle of 90° with adjacent sides at both ends, and this notched triangular area are formed as left and right claw portions 65 , 65 .

As shown in FIGS. 8 and 10, the relay member 62 is configured by a cylindrical member. The cylindrical member that constitutes the relay member 62 has a male thread into which the female threaded portion 85 of the check valve open maintenance member 64 with a water outlet (to be described later) is screwed on the outer peripheral surface of the one end opening 62a side in the direction along the center line of the cylindrical member. A portion 70 is provided, and a male threaded portion 71 to be screwed into the female threaded portion 25 of the hollow tube 26 is provided on the outer peripheral surface on the other end opening 62b side in the direction along the center line of the cylindrical member.

As shown in FIGS. 8 and 11, the pressing member 63 includes a sleeve 75 having an inlet into which the shaft 67 of the check valve opening member 61 is inserted and having one end closed. , and left and right horizontal shaft portions 76 provided so as to separate from one end of the sheath tube portion 75 in a direction perpendicular to the center line of the sheath tube portion 75 .

As shown in FIGS. 8 and 12, the water outlet check valve open maintenance member 64 is composed of, for example, a three-way switching valve having three inlets and outlets (ports) 80, 81, and 82. As shown in FIGS.
For example, the three-way switching valve that constitutes the check valve open maintenance member 64 with a water outlet includes a first inlet/outlet 80 formed by one end opening of the cylindrical portion 83 and a second inlet/outlet 80 formed by the other end opening of the cylindrical portion 83 . A configuration including, for example, a ball valve (not shown) for switching the flow path to the inside of a trifurcated pipe having an inlet/outlet 81 and a third inlet/outlet 82 formed by a side opening provided on the side of a cylindrical portion 83. should be used.
That is, the check valve open maintenance member 64 with a water outlet is, for example, a first entrance 80 and a second entrance 81 facing each other, and a line perpendicular to a straight line through which the center of the first entrance 80 and the center of the second entrance 81 pass. It is composed of a three-way switching valve having a third inlet/outlet port 82 that opens in the direction of .
An operating shaft 84 is provided to protrude outside the cylindrical portion 83 to operate the ball valve. A jig such as a wrench is engaged with the operating shaft 84 to rotate the operating shaft 84 to operate the ball valve. configured to operate.
A female threaded portion 85 configured to be screwed onto the male threaded portion 70 of the relay member 62 is formed on the inner peripheral surface of each of the entrances 80 , 81 , 82 .

A method of attaching the check valve open maintaining means 60A will be described.
First, as shown in FIG. 9, the bifurcated distal end portion 66 of the check valve opening member 61 is inserted into the injection hole 28 from the inner surface 21 side of the segment 20, and the left and right claw portions 65, 65 of the bifurcated distal end portion 66 are used to reverse the flow. A check valve opening member 61 is set so as to push open the valve bodies 46 , 46 of the stop valve 40 toward the outer surface 22 of the segment 20 .
Next, as shown in FIG. 10, the externally threaded portion 71 of the relay member 62 is screwed onto the internally threaded portion 25 of the hollow tube 26 for attachment.
As shown in FIG. 11, the shaft portion 67 of the check valve opening member 61 is inserted into the sheath tube portion 75 of the pressing member 63, and the pressing member 63 is set in a state of being pressed against the check valve 40 side.
Then, as shown in FIG. 12, the female threaded portion 85 of, for example, the first inlet/outlet 80 of the check valve open maintenance member 64 with water outlet is screwed to the male threaded portion 70 of the relay member 62 to form, for example, the female threaded portion 85. Both ends 77, 77 of the horizontal shaft portion 76 of the pressing member 63 are pressed by the bottom surface 86 of the threaded hole so that the ends 77, 77 are pressed against the one end surface 62e of the relay member 62. A check valve open maintenance member 64 with a water outlet is attached to the relay member 62 .
As described above, the check valve opening maintaining means 60A for maintaining the check valve 40 of the injection hole 28 in the flow path open state is attached to the injection hole 28 to configure the drain device 60 .
That is, by the draining device 60, the groundwater of the ground passes through the check valve 40 and the third inlet/outlet 82 serving as the water outlet of the check valve open maintaining member 64, and is drained to the inside of the lining. configured to

The three-way switching valve as the check valve open maintenance member 64 with a water outlet can operate a ball valve to, for example, connect the first inlet 80 and the third inlet 82 to close the second inlet 81. and the first entrance 80, the second entrance 81 and the third entrance 82 can be communicated, or the first entrance 80 and the third entrance 82 can be communicated by operating a ball valve. The second doorway 81 can be closed by allowing the first doorway 80 and the second doorway 81 to communicate with each other so that the third doorway 82 can be closed.

When groundwater from the natural ground outside the segment ring 30 is passed to the inside of the segment ring 30 using the drain device 60, one end of a drain hose or the like (not shown) is connected to the third inlet/outlet 82, and a ball By operating the valve, for example, by connecting the first entrance 80 and the third entrance 82 provided at positions orthogonal to each other and closing the second entrance 81, the groundwater from the natural ground is drained by the drainage device 60. For example, the water is drained to a drain tank installed in the starting shaft 100 through a hose, and is drained from the drain tank to the ground by a pump or the like.
When the tunnel to be constructed has an upward slope, groundwater is allowed to flow down from the third entrance 82 to the inside of the segment ring 30 without connecting a drain hose or the like to the third entrance 82, and the tunnel is installed in the starting shaft 100. It can be drained into a drainage tank or the like, and drained from the drainage tank to the ground using a pump or the like.

Also, when the flow path of the check valve 40 is clogged with earth and sand, etc., the second inlet/outlet 81 is opened and a rod or the like is inserted from the second inlet/outlet 81 to remove the earth and sand blocking the flow path of the check valve 40 . etc. can be removed, and clogging of the flow path can be eliminated.

The procedure for lifting prevention work is as follows.
For example, in the starting shaft 100, the cylindrical member 53 is attached in advance to the through hole 23 of the segment 20 to which the support device 50 is attached, and the segment 20 is transported to the tail portion 11. After the ring 30 is assembled, the threaded member 52 is manipulated (turned) to attach the threaded member 52 to the cylindrical member 53 . After the segment ring 30 is installed in the tunnel cavity from the rear end of the outer shell 3 of the shield machine 1, the tip 52t of the screw member 52 is protruded outward from the outer surface 22 of the segment 20 and hits the ground. The segment ring 30 is supported by the natural ground by hitting it.
In this way, after the segment ring 30 is installed in the tunnel cavity formed behind the shield machine 1 as the shield machine 1 advances, the screw member 52 is turned so that the tip 52t of the screw member 52 is pushed. Since the segment ring 30 is simply made to protrude outward from the outer surface of the segment ring 30 and abut against the natural ground, the work becomes very simple, and the construction of the shield tunnel can be smoothly performed.
The support device 50 is attached to the through holes 23 of the segments 20 arranged above the plurality of segment rings 30, 30, . . . For example, the support device 50 is arranged in a staggered manner along the extending direction of the plurality of segment rings 30, 30, . . .
In this case, as shown in FIG. 13, a supporting device 50 is provided in the through hole 23 of the segment 20 arranged above all the plurality of segment rings 30, 30, . Alternatively, the support device 50 may be provided only in the through hole 23 of the segment 20 arranged above an arbitrary segment ring 30 among the plurality of segment rings 30 installed in the segment ring installation section Y. may be provided.

The procedure for draining water is as follows.
After the segment ring 30 is installed from the rear end of the outer shell 3 of the shield machine 1 to the tunnel cavity, the check valve open maintenance means 60A is attached to the injection hole 28 of the segment ring 30 to configure the drain device 60.
By attaching the check valve open maintaining means 60A to all the injection holes 28 of the plurality of segment rings 30, 30, . . . A plurality of draining devices 60 are provided on a plurality of segment rings 30, 30, . . . .
Also, when the check valve opening maintaining means 60A is attached to the injection hole 28, groundwater flows down inside the segment ring 30. As shown in FIG. At this time, if the tunnel has an upward slope, the groundwater flowing down inside the segment ring 30 flows to the starting shaft 100. Therefore, after the groundwater is collected in a drainage tank or the like installed in the starting shaft 100, a pump or the like is pumped. Drain the water from the drainage tank to the ground. Further, if the tunnel does not have an upward slope, the underground water that has flowed down inside the segment ring 30 may be drained to the starting shaft 100 using a pump or the like.

In the specific construction work, natural water enters the tail void between the outer peripheral surface of the plurality of segment rings 30, 30, . . . , the plurality of segment rings 30, 30 installed in the segment ring installation section Y are supported on the ground by the supporting devices 5, 5, so that the plurality of segment rings installed in the segment ring installation section Y 30, 30 are prevented from floating, and the groundwater that has entered the tail void is guided to the inside of the plurality of segment rings 30, 30, . . . Since the water is drained through the face, it is possible to reduce the water pressure of the groundwater in the face part.

As a result of the drainage work, when it is determined that the water pressure of the ground in the face portion has fallen below the standard, the check valve open maintenance means 60A of the drainage device 60 is removed from the injection hole 28, and the segment ring installation section Y Tail voids between the outer peripheral surfaces of the plurality of installed segment rings 30, 30, and the ground are filled with a backfill material through check valves 40, 40, .
Then move on to normal work.

The support device 50 may remain attached to the through hole 23 , or the support device 50 may be removed from the through hole 23 and the check valve 40 may be attached to the through hole 23 .
Also, finally, the openings of the through holes 23 of the segment rings 30, 30 .

According to the shield construction method of Embodiment 1, when the water pressure of the groundwater in the ground at the face portion is higher than the standard, the plurality of segment rings 30, 30... are installed in the tunnel cavity as the shield machine 1 excavates. , a supporting device 50 is attached to a plurality of through-holes 23, 23, . , a plurality of injection holes 28, 28 (through holes in which check valves 40 are attached to the through holes 23) passing through the inner and outer surfaces of the plurality of segment rings 30, 30, . . . 60A is attached to form a draining device 60, and draining work is performed to drain groundwater from the natural ground inside the plurality of segment rings 30, 30, . In this case, a back-filling material filling operation is performed to fill gaps between the outer peripheral surfaces of the plurality of segment rings 30, 30 and the ground with the back-filling material.
That is, after it is determined that the water pressure of the groundwater in the ground at the face portion is higher than the standard, the drainage devices 60, 23, . . . Each time a new segment ring 30 is installed in the tunnel cavity after the water draining work by 60 is started, the drain devices 60, 60 attached to the plurality of through holes 23, 23, . . . Because the drainage work is performed by …, after it is judged that the water pressure of the groundwater in the ground at the face is higher than the standard, after it is judged that the environment at the face is under a high water pressure environment, A plurality of through holes 23, 23 in which a plurality of segment rings 30: 30 ... installed in the tunnel cavity are installed until it is judged that the water pressure of the groundwater in the ground has fallen below the standard Drainage work is continuously performed by the drain devices 60, 60 attached to . . . can now be lowered.
Further, as shown in FIG. 13, for example, the support device 50 is attached to the through holes 23 of the segments 20 arranged above the plurality of segment rings 30, 30, . . . During draining work, groundwater flows between the outer peripheral surface of the plurality of segment rings 30:30 installed in the tunnel cavity and the natural ground, and buoyancy is applied to the plurality of segment rings 30, 30. Even so, since the plurality of segment rings 30:30 are supported by the ground by the support devices 50, 50, the lifting of the plurality of segment rings 30, 30 can be prevented, and the plurality of segment rings 30, 30, . 30 can reduce the amount of deviation between the design installation position and the actual installation position.
Then, after it is determined that the water pressure of the groundwater in the ground at the face portion has decreased and has fallen below the standard, the outer peripheral surfaces of the plurality of segment rings 30, 30, . . . Since the backing material filling operation is performed to collectively fill the tail voids between the segment rings 30, 30, etc. installed in the segment ring installation section Y, the plurality of segment rings 30:30 can be stably supported on the natural ground. .

In addition, in Patent Document 1 described above, each time the shield machine advances, the work of filling the tail void with the backfill material, the work of attaching the drainage device, the work of drilling the backfill material, the work of draining the backfill material, the work of draining the backfill material, and the work of re-filling the backfill material. There was a problem that a lot of work such as filling work had to be done, and the construction period was long. In particular, every time the shield machine advances, the tail void is filled with the back-filling material, the back-filling material is drilled, and the tail void is filled with the back-filling material again, which is inefficient. is.
In contrast, in the first embodiment, when the water pressure of the groundwater in the ground at the face portion is higher than the standard, the through hole 23 of the segment ring 30 installed in the tunnel cavity is opened each time the shield machine 1 excavates. If the water pressure of the groundwater in the ground at the face portion falls below the reference level after performing the lifting prevention work and water draining work using the segment ring, the plurality of segment rings 30 installed in the segment ring installation section Y until then will be removed. Since the work of filling the tail void with the backfill material is performed collectively, the work is simplified, and the construction of the shield tunnel can be smoothly performed when the water pressure of the groundwater in the natural ground of the face part is higher than the standard.

Further, the work for preventing the ring-shaped lining body from floating up is carried out on the through-holes 23 other than the through-holes 23 used for draining water out of the through-holes 23 penetrating through the inner and outer surfaces of the plurality of segment rings 30, 30 . A threaded member 52 as a retractable member is provided so as to move back and forth between a state in which the tip 52t protrudes outward from the outer peripheral surface of the segment ring 30 and a state in which the tip 52t is positioned in the through hole 23. A plurality of segment rings 30, 30 . . . can prevent the segment rings 30, 30 from floating up, and can reduce the amount of deviation between the designed installation position and the actual installation position of the plurality of segment rings 30, 30, so that the shield tunnel can be constructed with high accuracy. can do

In addition, the draining work is performed by attaching to the through hole 23 a check valve open maintenance means 60A for keeping the check valve 40 installed in the through hole 23 open. After the open maintaining means 60A is removed from the through hole 23, the through hole 23 (injection hole 28) with the check valve 40 is connected to a backfilling material filling device (not shown), so that the drainage work can be performed smoothly. In addition, since the transition from draining work to backfilling work can be easily performed, construction of the shield tunnel can be performed smoothly.

Further, according to the support device 50 used in the shield construction method of the first embodiment, the check valve attachment portion formed on the center side in the extension direction of the through hole 23 penetrating through the inner surface 21 and the outer surface 22 of the segment 20 A female threaded portion 25 formed of a trapezoidal screw, a cylindrical member 53 having an outer peripheral surface provided with a male threaded portion 54 screwed to the female threaded portion 25 and an inner peripheral surface provided with a female threaded portion 55, and a female threaded portion of the cylindrical member 53 A threaded member 52 as a retractable member is provided so as to be threadedly attached to the segment 20 so that the tip 52t protrudes outward from the outer surface of the segment 20 and the tip 52t is positioned in the through hole 23. Therefore, after the support device 50 is attached to the through hole 23 of the segment ring 30 and the segment ring 30 is installed from the rear end of the outer shell 3 of the shield machine 1 to the tunnel cavity, the tip 52t of the screw member 52 is project outward from the outer surface 22 of the segment 20 and abut against the ground, the segment ring 30 can be supported on the ground and the segment rings 30, 30, . . . can be prevented from rising.

According to the drain device 60 used in the shield construction method of the first embodiment, the inner surface and the outer surface of the segment ring 30 installed in the tunnel cavity formed behind the shield machine 1 as the shield machine 1 advances. A check valve 40 attached to a through-hole 23 penetrating through the segment ring 30, and the check valve 40 is opened so that the groundwater of the natural ground passes through the check valve 40 and is drained inside the segment ring 30. and a check valve open maintaining means 60A configured to maintain at.
The check valve 40 includes a cylindrical portion 41 functioning as an attachment portion to the through hole 23 and a valve portion 42. The valve portion 42 includes a valve body portion 44 and a valve seat 45. The valve body portion 44 includes left and right valve bodies 46, 46 and a valve body support portion 47, and the valve bodies 46, 46 are rotatable via a boundary portion between the valve body support portion 47 and the valve bodies 46, 46. The valve seat 45 is formed by an annular wall surface protruding from the inner peripheral surface of the cylindrical portion 41 toward the center line of the cylindrical portion 41 .
The check valve open maintenance means 60A includes a check valve open member 61, a relay member 62, a pressing member 63 that presses the check valve open member 61, and a check valve open maintenance member 64 with a water outlet.
The check valve opening member 61 is inserted into the injection hole from the inner surface 21 side of the segment ring 30 and has a bifurcated distal end provided with left and right claws 65, 65 for pushing open the left and right valve bodies 46, 46 of the check valve 40. 66, and a shaft portion 67 extending rearward from a center portion 66e at the rear end of the bifurcated tip portion 66. As shown in FIG.
The relay member 62 has a male threaded portion 70 to which the threaded portion of the threaded member of the check valve open maintenance member with a water outlet is screwed on the outer peripheral surface on the one end opening 62a side in the direction along the central axis. It is composed of a cylindrical member provided with a male threaded portion 71 screwed into a female threaded portion such as a trapezoidal screw of the injection hole on the outer peripheral surface on the side of the other end opening 62b in the longitudinal direction.
The pressing member 63 includes a sheath tube portion 75 having an inlet into which the shaft portion of the check valve opening member 61 is inserted on the distal end side, and one end of which is closed. It is formed in a T shape with left and right lateral shaft portions 76 provided so as to be separated from each other in a direction perpendicular to the axis.
For example, a three-way switching valve that constitutes the check valve open maintenance member 64 with a water outlet is screwed onto the male screw portion 70 of the relay member 62 so that both ends of the horizontal shaft portion of the pressing member 63 are connected to one end of the relay member 62 . By being attached so as to be pressed against the opening 62a, the check valve is maintained in an open state, and groundwater from the natural ground flows through the check valve and the water outlet of the check valve open maintenance member 64. It was configured to drain through to the inside of the segment ring.
By using the draining device 60, it is possible to easily drain groundwater flowing between the outer peripheral surface of the segment ring 30 installed in the tunnel cavity and the natural ground to the inside of the segment ring 30. Became.

According to the drain device 60 used in the shield construction method of Embodiment 1, the check valve open maintenance member 64 with a water outlet is composed of a three-way switching valve having three inlets and outlets (ports) 80, 81, 82. The female threaded portion 85 of the first inlet/outlet 80 is screwed to the male threaded portion 70 of the relay member 62, the three-way switching valve is attached to the relay member 62, and the first inlet/outlet 80 and the third inlet/outlet 82 are provided at positions perpendicular to each other. By closing the second inlet/outlet 81 by communicating with the second inlet/outlet 81, the draining work of draining the groundwater that has flowed between the outer peripheral surface of the segment ring 30 and the natural ground to the inside of the segment ring 30 via the drain device 60 can be facilitated. In addition, when the flow path of the check valve 40 is clogged with earth and sand, the second inlet/outlet 81 is opened and a rod or the like is inserted from the second inlet/outlet 81 to open the flow path of the check valve 40. Therefore, the draining device 60 can easily perform the draining work and the clogging release work of the check valve 40.例文帳に追加

Embodiment 2
A threaded tube member 520 as shown in FIG. 14 may be used instead of the threaded member 52 .
The threaded tube member 520 includes a threaded tube 510 made of, for example, synthetic resin or iron, and a lid 530 .
The threaded tube 510 includes a male threaded portion 511 formed on the entire outer peripheral surface, and a through hole 522 formed on the outer peripheral surface on the other end opening 521 side and passing through the inner and outer surfaces of the tube. One or more through holes 522 are formed.
The lid 530 is formed with a female threaded portion 531 screwed into the male threaded portion 511 on the side of the one end opening 523 of the threaded tube 510 on the inner peripheral surface so that the one end opening 523 of the threaded tube 510 can be opened and closed. It is formed by a circular cylindrical lid with one end that is detachably configured to close 523 .

The other end opening 521 side of the threaded tube member 520 is inserted into the through hole 23 from the opening on the segment inner surface 21 side of the through hole 23 , and the male threaded portion 511 of the threaded tube 510 is screwed into the female threaded portion 55 of the cylindrical member 53 to screw. The other end opening 521 side of the pipe 510 protrudes outward from the outer surface of the segment ring 30 and abuts against the natural ground, thereby supporting the segment ring 30 on the natural ground. After that, the lid 530 is removed, one end opening 523 is opened, and a drainage hose or the like is connected to the one end opening 523, so that groundwater from the ground flows through the through hole 522, the inside of the screw pipe 510, the one end opening 523, and the drainage. The water is drained inside the segment ring 30 via a hose or the like.

By using the threaded pipe member 520 instead of the threaded member 52 of the first embodiment, it is possible to perform both lifting prevention work and water draining work.

In addition, the threaded pipe members 520 are attached to all the through holes 23 of the plurality of segment rings 30, 30, . After it is determined that the water pressure of the ground in the face portion has decreased to below the standard, the threaded pipe member 520 is removed from the through hole 23, and the check valve 40 is attached to the through hole 23 from which the threaded pipe member 520 has been removed. Alternatively, the tail voids on the outside of the plurality of segment rings 30, 30, . . .

Further, by forming in the segment 20 a through-hole provided with a female thread portion into which the male thread portion formed on the outer peripheral surface of the screw member 52 and the screw tube member 520 as the advancing/retracting member can be screwed, the screw member 52 and the screw can be Instead of using the cylindrical member 53 that guides the advance and retreat of the pipe member 520, a supporting device may be used in which the screw member 52 and the screw pipe member 520 are directly screwed into the female threaded portion of the through hole of the segment 20. .

Further, the trapezoidal thread as the female thread portion 25 provided on the central side in the direction along the center line of the through hole 24, and the screw member or the threaded tube member which is directly screwed to the trapezoidal thread and configured to advance and retreat. A structured support device may also be used.

Conditions such as the water pressure condition of the ground in the face portion, the number of segment rings 30 installed in the segment ring installation section Y, etc. In cases such as when the number of segment rings 30 installed in the installation section Y is small, if it is determined that lifting prevention work for the plurality of segment rings 30 installed in the segment ring installation section Y is unnecessary, Installed in the segment ring installation section Y, after it is determined that the water pressure of the ground in the face portion has decreased below the standard by performing the draining work without performing the lifting prevention work for the segment rings 30, 30 ... The tail voids between the outer peripheral surfaces of the plurality of segment rings 30, 30, .
That is, when the water pressure of the groundwater in the ground at the face portion is higher than the standard, a plurality of segment rings 30, 30, . . . By using a plurality of through holes 23 penetrating through the inner and outer surfaces of the segment rings 30, 30, draining work for draining groundwater from the ground inside the plurality of segment rings 30, 30 is performed. When the water pressure of the groundwater in the ground in the part falls below the standard, a backfill material filling operation is performed to fill the gap between the outer peripheral surface of the plurality of segment rings 30, 30 and the ground with the backfill material. You can do it.

Further, whether or not the water pressure of the groundwater in the ground at the face portion is higher than the standard is determined, for example, by an earth pressure gauge (not shown) provided on the partition wall 4 to measure the earth pressure in the chamber 5. It is determined whether or not the pressure value is higher than a reference design earth pressure value (for example, 0.3 MPa).
That is, during excavation work of the shield machine 1, the earth pressure value in the chamber 5 measured by the earth pressure gauge and displayed on the display means in the driver's seat (not shown) is observed, and the earth pressure value is higher than the design earth pressure value. If the soil pressure in the chamber 5 becomes lower than the design soil pressure value after draining the water without filling the backfill material in the segment ring installation section Y, Installed in the segment ring installation section Y, the segment ring installation section Y is filled with a backing material to fill the tail void, which is the gap between the outer peripheral surface of the plurality of segment rings 30, 30 ... and the ground. Complete the shield tunnel at Y.
Specifically, when the earth pressure value in the chamber 5 is high, from the difference between the earth pressure value and the design earth pressure value, the segment required for the earth pressure value in the chamber 5 to become lower than the design earth pressure value The length of the ring installation section Y is predicted, and the soil in the chamber 5 is removed at the time when the construction in the segment ring installation section Y of the predicted length (construction without water removal work and backfill material filling work) is completed. Check the pressure value, and if the earth pressure value at that time is higher than the design earth pressure value, extend the length of segment ring installation section Y, and if the earth pressure value at that time is lower than the design earth pressure value For example, by performing a back-filling material filling operation of filling the tail void, which is a gap between the outer peripheral surface of the plurality of segment rings 30, 30 ... installed in the segment ring installation section Y by the time point and the ground, with the back-filling material. The shield tunnel should be completed in the segment ring installation section Y.

Moreover, although an example of using the segment 20 made of reinforced concrete as the lining member has been shown, a segment made of steel, a segment made of ductile cast iron, a segment made of a composite structure of concrete and steel, etc., other than made of reinforced concrete, can be used. I don't mind.

1 shield machine, 3 outer shell, 11 tail part, 20 segment (lining member),
23 through hole, 30 segment ring (annular covering body), 40 check valve,
52 screw member (advance/retreat member), 60A check valve open maintenance means.

Claims (4)

An annular lining body formed by a plurality of lining members arranged along the inner peripheral surface of the tail portion of the outer shell of the shield machine that excavates the natural ground is moved by the shield machine as it excavates. In the shield construction method that is installed in the tunnel cavity formed behind the
The earth pressure value measured by the earth pressure gauge installed on the bulkhead in the chamber of the shield machine is higher than the design earth pressure value, which is the reference, to determine whether the water pressure of the groundwater in the ground at the face part is higher than the standard. Judging by whether it is high or not, if the water pressure of the groundwater in the ground in the face part is below the standard, every time a ring lining is installed in the tunnel cavity as the shield machine advances, the ring lining When the backfill material filling work is performed to fill the gap between the outer peripheral surface of the body and the ground, and the water pressure of the groundwater in the ground at the face part is higher than the standard, A plurality of annular lining bodies are installed in the tunnel cavity by using a plurality of through holes penetrating through the inner and outer surfaces of the plurality of annular lining bodies. If the water pressure of the groundwater in the groundwater in the face part falls below the standard due to the drainage work to drain the groundwater of the natural ground, A shield construction method characterized by performing a backfilling material filling operation of filling the gap of the backfilling material. 2. The shield construction method according to claim 1, wherein a plurality of annular lining bodies installed in the tunnel cavity are prevented from being lifted up and drained. The work to prevent the ring-shaped lining body from floating up is performed by inserting the end of the ring-shaped lining body into the through-hole other than the through-hole used for draining water among the through-holes passing through the inner and outer surfaces of the plurality of ring-shaped lining bodies. A retractable member is mounted so that it can move back and forth between a state where it projects outward from the outer peripheral surface and a state where the tip is positioned in the through hole, and the tip of the retractable member is positioned outside the outer peripheral surface of the annular covering body. 3. The shield construction method according to claim 2, wherein the plurality of annular lining bodies are supported on the natural ground by protruding and abutting against the natural ground. The water draining work is performed by attaching a check valve open maintenance means for keeping the check valve installed in the through hole in an open state. 4. The shield construction method according to any one of claims 1 to 3, wherein a device for filling a backing material is connected to the through hole after removing the shield from the through hole.

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