JPH05156900A - Method and segment for lowering underground water level in constructing segment type tunnel - Google Patents

Abstract

PURPOSE:To save labor and cost in lowering underground level at any location of segment type tunnel construction. CONSTITUTION:The level of underground water in ground G above a tunnel T by collecting the underground water into a water collecting part 3 of a segment 1 installed in an adit 15, pumping up the underground water from a starting shaft 14 with a water collecting pipe P onto ground surface. This method can substantially reduce on-ground equipment, labor and cost for work, and is effective particularly for mountain tunnels and deep tunnels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has numerous segments,
The present invention relates to a method of lowering the groundwater level in the ground above the tunnel when the tunnel is installed and connected to the inner surface of the excavation mine, and a segment suitable for implementing this method.

[0002]

2. Description of the Related Art When a tunnel wall is formed by a large number of segments by a so-called shield construction method to construct a tunnel, the groundwater level of the ground above the tunnel is lowered to minimize the outflow of groundwater into the tunnel. Is being done.

As an example of such a method, there is a so-called deep well method in which a plurality of pipes are passed from the ground to the ground above the tunnel and groundwater is pumped to the ground through the pipes.

[0004]

The above construction method is difficult to apply in urban areas because a space for installing equipment for passing pipes into the ground is required on the ground. Also,
The construction itself requires large-scale equipment, and it takes a lot of labor and cost to pass many pipes through the ground, and this tendency is remarkable especially in the case of mountain tunnels and deep tunnels.

The present invention has been made in view of the above circumstances, and can be applied without selecting a tunnel construction site, and can reduce labor and cost, and groundwater for constructing a segment type tunnel. The aim is to provide a method of lowering the position and suitable segments in which this method can be implemented.

[0006]

According to a first aspect of the present invention, when a plurality of segments are installed and connected to the inner surface of an excavation mine to construct a tunnel, the groundwater level in the ground above the tunnel is lowered. In the method, the groundwater collecting part is provided on the outer peripheral side of the tunnel of the segment, and the groundwater is pumped from the collecting part to the ground through a start shaft of the excavation shaft by a water collecting pipe. There is.

According to a second aspect of the present invention, there is provided a segment which is installed on an inner surface of an excavation pit and which is connected to form a tunnel wall, wherein a water collecting portion is provided on an outer peripheral side of a tunnel of a segment body. From at least a mesh-shaped cover that constitutes the outer peripheral surface of the water collecting portion, and an interstitial material such as silica sand that is filled in the space between the cover and the segment body and that cannot be removed from the cover and through which groundwater can pass. In addition, the segment main body is characterized in that a water collecting hole is formed in the segment main body, which connects both the outer peripheral side and the inner peripheral side of the tunnel.

[0008]

According to the method of lowering the groundwater level in the construction of the segment type tunnel of the present invention, it is not necessary to pass a plurality of pipes for collecting water to the ground as in the conventional case, and the facility on the ground is extremely small. It can also be applied to urban areas, and the labor and cost involved in construction can be significantly reduced. Further, since the groundwater is collected in the segment forming the tunnel wall, the water level of the groundwater can be easily lowered regardless of the depth or the place, and therefore it is particularly effective for the mountain tunnel and the deep tunnel.
Further, according to the segment of the present invention, the above method can be easily and surely carried out, which is preferable.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, an embodiment of a segment according to the present invention will be described with reference to FIGS. The segment 1 of the present embodiment is made of steel, and the water collecting portion 3 is provided on the surface of the segment main body 2 made of steel curved along the inner surface of the excavation pit of the tunnel to be constructed, which is the outer peripheral side of the tunnel. It has a basic configuration.

The segment main body 2 extends in the curving direction and extends between a pair of main girders 4 arranged so as to face each other.
The plate-shaped skin plate 5 is stretched along the bending direction and has an H-shaped cross section. The skin plate 5 is welded to the center of the main girder 4 in the height direction. Here, in the main girder 4,
When a portion on the outer peripheral side of the skin plate 5 is an outer peripheral portion 4a and a portion on the inner peripheral side is 4b, a flat end plate 6 is stretched between both ends in the bending direction of the inner peripheral portions 4b of the pair of main girders 4, These end plates 6 are welded to the inner peripheral portion 4b of the main girder 4 and the skin plate 5. A water collecting hole 5a is formed in the center of the skin plate 5.

The water collecting portion 3 has a mesh-shaped cover 7 stretched between the outer peripheral edges of the outer peripheral portions 4a and both ends of the outer peripheral portion 4a in the bending direction of the pair of main girders 4, and the skin of the segment body 2. Outer peripheral portion 4a of plate 5 and main girder 4
Silica sand (inclusions) filled in the space surrounded by
It consists of and. The silica sand 8 has a function of collecting groundwater, is slightly rougher than the eyes of the cover 7, cannot be removed from the cover 7, and can pass groundwater. The outer peripheral side of the cover 7 is curved along the segment body 2, and an angle member 9 is attached to the outer peripheral portion 4a and the cover 7 in order to maintain the curved state.

On the outer peripheral surface of the skin plate 5, a mesh-like shutter 10 for preventing the silica sand 8 from falling off from the water collecting hole 5a is stretched. A water collecting cylinder 11 is attached to the inner peripheral surface of the skin plate 5 to guide the groundwater passing through the silica sand 8 to the inner peripheral side of the segment body 2 through the water collecting hole 5a. A joint 12 for connecting the water collecting cylinder 11 to a water collecting pipe P described later is attached to the tip of the water collecting pipe 11.

A bolt through hole 13 is provided in the inner peripheral portion 4b of the main girder 4 and the end plate 6 for connecting the segments by bolt connection.

Now, a method of constructing a tunnel by using the segment 1 having the above structure and lowering the groundwater level of the tunnel will be described below.

As shown in FIG. 3, a side shaft (excavation pit) 15 for constructing a tunnel by a shield machine or the like is excavated from the bottom of the starting shaft 14 drilled in the ground G.
A ring 1A formed by connecting the segments 1 in the circumferential direction and a ring 16A formed by connecting ordinary segments (made of steel or concrete) 16 in the circumferential direction are provided on the inner surface of the shaft 15 in the excavating direction. Install towards it. In this case, the ring 16 with the normal segment 16
When three A's are connected, the ring 1 by the above segment 1
The pattern for connecting one A is repeated, that is, the ring 1A by the segment 1 is connected at a ratio of one to four, and these rings 1A and 16A are installed in the shaft 15.

In the tail portion of the shield machine, as shown in FIG. 4, usually, an annular seal material 17 is doubly attached to the inner peripheral portion of the skin plate M of the shield machine, and grease is provided between them. G is filled to prevent the backing material filled between the installed segment 1 (16) and the ground G from entering the shield machine. Therefore, when the tail machine is propelled with the segment 1 installed in this state, the grease G enters the silica sand 8 through the cover 7, and the water collecting portion 3 does not exhibit the water collecting function.

Therefore, as shown in FIG. 4, a tubular blocking sheet 19 made of flexible thin rubber or the like is provided on the inner peripheral portion of the skin plate M via an annular bracket 18.
The blocking sheet 19 is detachably attached.
This prevents the grease G from entering the water collecting section 3. Then, as shown in FIG. 5, when the seal material 17 has finished passing through the segment 1, the seat 19 is removed from the bracket 18. The seat 19 has a segment 16 as shown in FIG.
Between the ground and the ground G, and finally buried in the backing material.

When the tunnel T is constructed as described above, the water collecting pipe P is introduced from the starting shaft 14 into the tunnel T.
Is introduced and the joint 12 of each segment 1 constituting the ring 1A and the water collecting pipe P are connected via another pipe or the like not shown. Then, on the ground, the inside of the water collecting pipe P is sucked by a pump or the like (not shown).

Groundwater existing in the ground G above the tunnel T is collected in the water collecting portion 3 of each segment 1. That is, the groundwater is absorbed by the silica sand 8 through the mesh-shaped cover 7. Then, the groundwater in the silica sand 8 passes through the shutter 10 and reaches the inside of the water collecting pipe P through the water collecting hole 5a, the water collecting cylinder 11 and the like, and is pumped to the ground from the water collecting pipe P.

As described above, by pumping the groundwater collected by each segment 1 to the ground by the water collecting pipe P, the groundwater level W above the tunnel T is lowered.

When it is confirmed that the groundwater level W has decreased to a desired level, the water collecting pipe P is eliminated, and the inner peripheral surfaces of the rings 1A and 16A are appropriately subjected to secondary lining to finally Get the tunnel T.

According to the method of lowering the groundwater level by collecting the groundwater by using the segment 1 as in the present embodiment, a plurality of pipes for collecting the water are provided in the ground as in the conventional case. Since it is not necessary to pass it through, and only a pump for collecting water needs to be installed on the ground, the equipment on the ground will be extremely small, and the labor and cost for construction will be greatly reduced.

Also, the segment 1 forming the tunnel wall
Since groundwater is collected in the groundwater, it is possible to easily lower the groundwater level irrespective of the depth and location. Therefore, it is especially effective for mountain tunnels and deep tunnels.

7 and 8 show another embodiment of the segment which is an alternative to the segment 1.

The segment 20 has a curved plate shape, and is formed on the convex outer surface of the concrete segment main body 21 having a water collecting hole 21a at the center, which is the outer peripheral side of the tunnel.
It has a basic configuration in which a water collecting section 22 is provided.

The water collecting portions 22 are fixed to both ends in the width direction of the outer peripheral surface of the segment main body 21, and have a pair of channel members 23 curved along the segment main body 21 with a U-shaped cross section in which inner corners face each other. , The mesh-shaped cover 24 stretched over the channel members 23 and curved along the segment body 21, and the space surrounded between the channel members 23 and the cover 24 is filled with the same material as in the previous embodiment. It is composed of silica sand 8.

The mesh-shaped cover 24 has a roughness of the eyes such that the silica sand 8 does not fall off, as in the previous embodiment, and the outer surface of the segment main body 21 has the water collecting hole 2 on its outer surface.
A mesh-shaped shutter 25 for preventing the silica sand 8 from falling off from 1a
Is stretched.

The segment body 21 is provided with a joint fitting 26 for connecting the segments by bolts.
Is provided.

By installing this segment 20 in the shaft 15 instead of the segment 1 of the previous embodiment,
Similarly, groundwater can be collected from the water collecting part 22 to lower the water level. In this case, groundwater is absorbed into the silica sand 8 through the cover 24, passes through the shutter 25, passes through the water collecting hole 21a, and then from the water collecting pipe P connected to the water collecting hole 21a by another pipe or the like. Pumped to the ground.

[0031]

As described above, according to the method of lowering the groundwater level in the construction of the segment type tunnel of the present invention, when a large number of segments are installed and connected to the inner surface of the excavation hole to construct the tunnel, A method of lowering the groundwater level in the ground above the tunnel, where a groundwater collecting part is provided on the outer peripheral side of the tunnel of the segment, and from this collecting part, the starting shaft of the excavation pit is connected by a water collecting pipe. Since it is characterized by pumping groundwater to the ground after that, it is not necessary to pass multiple pipes for collecting water to the ground as in the past, and the equipment on the ground is extremely small and can be applied to urban areas. In addition, the labor and cost required for construction work can be significantly reduced, and groundwater is collected in the segment that forms the tunnel wall. Easily it can reduce the level of ground water without, therefore, is particularly effective in the mountain tunnel or deep tunnel.

Further, according to the segment of the present invention, a water collecting portion is provided on the outer peripheral side of the tunnel of the segment body, and the water collecting portion includes at least a mesh-shaped cover constituting the outer peripheral surface of the water collecting portion. , A space between the cover and the segment body is filled with a non-fallable inclusion such as silica sand that can pass groundwater,
Since the segment main body is formed with a water collecting hole that communicates both the outer peripheral side and the inner peripheral side of the tunnel, the method of the present invention can be carried out easily and reliably. ..

[Brief description of drawings]

FIG. 1 is a perspective view of a segment of one embodiment of the present invention.

FIG. 2 is a sectional view of the segment.

FIG. 3 is a side view of a tunnel for explaining an embodiment of the method of the present invention.

FIG. 4 is a partial cross-sectional side view of the first stage showing an example of a propulsion method of the shield machine.

FIG. 5 is a partial cross-sectional side view of the second stage.

FIG. 6 is a partial cross-sectional side view of the third stage.

FIG. 7 is a perspective view of a segment of another embodiment of the present invention.

FIG. 8 is a sectional view of the same segment.

[Explanation of symbols]

 1, 20 segment 2, 21 segment main body 3, 22 water collecting part 5a, 21a water collecting hole 7, 24 cover 8 silica sand (inclusion) 14 starting vertical shaft 15 side shaft (excavation pit) G ground T tunnel W groundwater level

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirohide Hashimoto 2-6-21 Yaesu, Chuo-ku, Tokyo Rose Bay Yaesu Building Ishikawajima Kenzai Kogyo Co., Ltd. In-house

Claims (2)

[Claims] 1. A method for lowering the groundwater level of ground above the tunnel when installing and connecting a number of segments to the inner surface of an excavation pit to construct a tunnel, the method comprising: A method for lowering the groundwater level in the construction of a segmented tunnel, characterized in that a groundwater collecting section is provided and groundwater is pumped to the ground from this collecting section through a water collection pipe through a start shaft of the excavation pit. 2. A segment which is installed on the inner surface of an excavation mine and which is connected to a plurality to form a tunnel wall, wherein a water collecting portion is provided on the outer peripheral side of the tunnel of the segment body, and the water collecting portion is at least the water collecting portion. The segment main body is composed of a mesh-shaped cover that forms the outer peripheral surface of the water portion, and an interstitial material such as silica sand that is filled in the space between the cover and the segment main body and that cannot be removed from the cover and through which groundwater can pass. In the segment, a water collecting hole is formed to connect the outer circumference side and the inner circumference side of the tunnel.