JP3228850B2 - Shield method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield construction method suitable for use, for example, when soil pressure from the ground surrounding a tunnel to be built varies depending on the location.

[0002]

2. Description of the Related Art As is well known, when constructing a tunnel using a shield method, a segment forming an inner wall surface of the tunnel is assembled behind the shield excavator while excavating the ground. At this time, the lining thickness of the tunnel and the thickness of the segment are determined based on the inner diameter required for the tunnel to be built and the soil water pressure applied to the tunnel from the surrounding ground, and accordingly, the outside of the shield excavator. The diameter is set. However, due to changes in the installation depth and geology of the tunnel, the magnitude of the soil water pressure acting on the tunnel from the surrounding ground may differ from place to place. In general, the lining thickness of the entire tunnel is determined.

[0003]

However, the above-mentioned conventional shield method has the following problems. First, when the lining thickness of the tunnel is determined according to the maximum soil pressure as described above, the tunnel has an unnecessarily thick lining in a place where the soil pressure is low, which is uneconomical. There is a problem.

[0004] In order to solve such a problem, there is a shield method in which the lining thickness of the tunnel is changed according to the level of soil water pressure. In this method, tunnels are excavated from the side with high soil water pressure and the side with low soil water pressure using, for example, two types of shield excavators having different outer diameters, and both tunnels are finally joined. However, this method requires the preparation of multiple shield excavators and increases the number of shafts to be built, which leads to equipment costs,
There is a problem that the construction cost increases significantly.
In addition, this method is not practical because the cost is further increased when places with high and low soil water pressure are alternately continuous.

As described above, in the conventional shield method, there is room for cost reduction when a tunnel is constructed in a place where the soil water pressure changes. The present invention has been made in consideration of the above points, and has as its object to provide a shield method capable of economically constructing a tunnel even when soil pressure is different.

[0006]

The invention according to claim 1 is
An outer diameter that is substantially the same as the inner diameter of the outer seal member in a skin plate that is substantially cylindrical and has an outer seal member that prevents intrusion of muddy water and earth and sand into its tail while excavating the ground in front with a shield excavator. A tunnel is constructed on the rear side by assembling the large-diameter segment having a large diameter, and then a reaction force is applied to the already assembled large-diameter segment with a jack provided on the shield excavator. After the shield excavator is moved forward, an annular inner seal member having an inner diameter smaller than that of the skin plate is disposed inside the skin plate without being fixed, and then, inside the inner seal member, And assembling a small-diameter segment having substantially the same outer diameter as the inner diameter, and integrally fixing the small-diameter segment and the inner seal member. And then, by advancing the shield excavator to obtain a reaction force to said small-diameter segment by the jack,
The outer seal member and the inner seal member are in a state where they are doubly positioned inside and outside, and thereafter, the tunnel is constructed by assembling the small diameter segments inside the inner seal member while excavating the shield excavator. It is characterized by going.

According to a second aspect of the present invention, a shield excavator is provided with an outer seal member at a tail portion of a substantially cylindrical skin plate for preventing intrusion of muddy water and earth and sand. An inner seal member having an inner diameter smaller than the skin plate is detachably mounted, and while excavating the ground in front with the shield excavator, an outer diameter substantially equal to the inner diameter of the inner seal member in the skin plate. Assemble a small diameter segment with a and build a tunnel behind it,
Thereafter, first, after separating the inner seal member and the outer seal member, the jack obtains a reaction force on the already assembled small-diameter segment to advance the shield excavator to move the inner seal member rearward. After that, while tunneling the shield excavator, a large-diameter segment having an outer diameter substantially equal to the inner diameter of the outer seal member of the skin plate is assembled inside the outer seal member to construct a tunnel. It is characterized by doing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a shield method according to the present invention will be described below with reference to FIGS. Here, first, a shield excavator used in the shield method will be described. As shown in FIG. 1, the shield excavator 1 is provided with a cutter 2 for excavating the ground G on the front side in the excavation direction, and on the rear side of the cutter 2,
It has a schematic configuration provided with a skin plate 3 having a cylindrical shape in a sectional view, which forms the outer shell. In the skin plate 3, a cutter rotating motor 4 for driving the cutter 2, a mud feeding pipe 5 and a mud discharging pipe 6 for discharging the slip backward, and a segment S forming a tunnel T to be constructed. , A shield jack 9 for moving the shield excavator 1 forward by obtaining a reaction force on the segment S assembled into a predetermined shape by the erector 7, and the like.

As shown in FIG. 2, an annular outer seal (outer seal member) 10 is provided on the inner peripheral surface of the tail portion 3a of the skin plate 3 so that earth and sand or muddy water is applied to the skin from the outside of the assembled segment S. The intrusion into the plate 3 is prevented. This outer seal 1
0 has a configuration in which a plurality of seal members 10a, 10a,... Are provided in the axial direction of the skin plate 3.

Further, as shown in FIG. 3, an inner seal (inner seal member) 11 having a substantially cylindrical shape and a constant thickness can be mounted inside the tail portion 3a of the skin plate 3. . The inner seal 11 can be divided into a plurality of pieces having the same cross-sectional shape in the circumferential direction. On the inner peripheral surface of the inner seal 11,
A plurality of seal members 11a, 11a,... Are provided.

The shield excavator 1 having such a configuration
In the state where the inner seal 11 is not attached, a large diameter segment (large diameter segment) S1 having an outer radius of curvature substantially equal to the inner radius of curvature of the skin plate 3 is assembled to construct the tunnel T. ing. When the inner seal 11 is attached to the tail 3a of the skin plate 3, a small-diameter segment (small-diameter segment) S2 having an outer radius of curvature substantially equal to the radius of curvature of the inner peripheral surface of the inner seal 11 is assembled. T
Is to be built. Here, the large-diameter segment S1 and the small-diameter segment S2 differ only in the outer radius of curvature, and have the same inner radius of curvature.
Therefore, the portion of the tunnel T formed by the large-diameter segment S1 and the portion formed by the small-diameter segment S2 have the same inner diameter except for the outer diameter, that is, the lining thickness varies. It has become.

Next, the shield excavator 1 having such a configuration will be described.
A method of constructing the tunnel T using the method will be described. Here, for example, a case will be described in which a tunnel T is dug from a portion where the soil pressure acting on the surrounding ground G is high to a portion where the soil water pressure is low. At this time, the inner seal 11 is not attached to the tail portion 3a of the skin plate 3 of the shield excavator 1, as shown in FIG.

Then, the shield excavator 1 is lowered from a shaft not shown to a predetermined depth in the ground G, and the ground G is
, The large-diameter segments S 1, S 1,... Transported from the shaft (not shown) are assembled by the erector 7 in the skin plate 3 of the shield excavator 1.

Then, when the shield excavator 1 reaches the portion where the soil water pressure is low, first, as shown in FIG.
The spacers 13, 13,... Are assembled in a ring shape so as to be continuous with the large-diameter segment S1 that has already been assembled. This spacer 13 has a length Ls that is equal to that of the large-diameter segment S1.
Is set shorter than the length L1.

Next, each shield jack 9 is extended. Then, the shield jack 9 becomes the large-diameter segment S.
The shield excavator 1 moves forward by the length Ls of the spacer 13 by obtaining a reaction force from the spacer 13 assembled continuously with the spacer 13.

Subsequently, as shown in FIG. 2B, the spacer 13 is removed. A slide guide 14 is attached to the inner peripheral surface of the tail portion 3a of the skin plate 3 immediately before the outer seal 10, for example, by welding. The slide guides 14 are arranged on the entire inner circumferential surface of the skin plate 3 or at regular intervals in the circumferential direction.

Then, as shown in FIG. 3A, the inner seal 11 is assembled in a ring shape inside the skin plate 3. At this time, in order to integrally join the inner seal 11 made of a plurality of members by, for example, welding, the sealing member 11a 'on the base end portion 11b side of the inner seal 11 is removed and attached after welding. . Next, brackets 1 having an L-shaped cross section are provided at a plurality of positions in the circumferential direction of the base end portion 11b of the assembled inner seal 11.
5 is detachably attached with bolts or the like.

Thereafter, as shown in FIG. 3B, a small-diameter segment S for a joining portion is provided inside the inner seal 11.
Assemble 2 '. Small diameter segment S2 'for this joint
Is the length L1 of the large diameter segment S1 and the length of the spacer 13
And the length Ls (see FIG. 2). Then, the small-diameter segment S2 'for the joining portion and the inner seal 11 are integrally fixed with the mounting bolts 16.

After the assembly of the inner seal 11 and the small-diameter segment S2 'for the joint portion is completed,
As shown in FIG. 3C, each shield jack 9 is extended to move the shield excavator 1 forward (it goes without saying that the ground is excavated with the cutter 2 at this time). Then, the skin plate 3 and the inner seal 11 are not joined, and the inner seal 11 is fixed to the small-diameter segment S2 '.
Does not move forward, and the outer seal 10 is
It is designed to move forward together. At this time, the slide guide 14 slides on the outer peripheral surface of the inner seal 11, and the bracket 15 functions as a stopper.

Next, the bolts (not shown) are removed to remove the bracket 15, and the mounting bolts 16 are removed to release the inner seal 11 from being fixed to the small-diameter segment S2 '. Then, the base end portion 1 of the inner seal 11
1b and the slide guide 14 are joined by, for example, welding. As a result, the inner seal 11 is joined to the skin plate 3 via the slide guide 14, and the outer seal 10 and the inner seal 11 are in a state of being located inside and outside.

Then, while excavating the ground G with the cutter 2, as shown in FIG.
, Are carried in, and are assembled into a predetermined shape by the erector 7 (see FIG. 1).

Thereafter, when the shield excavator 1 again reaches the portion where the soil pressure is high, first, the welding portion between the skin plate 3 and the slide guide 14 and the welding portion between the slide guide 14 and the thinner seal 11 are formed. And cut off.

Next, as shown in FIG. 4B, a large-diameter segment S1 is assembled so as to be continuous with the assembled small-diameter segment S2. Then, after that, each shield jack 9 is extended and the shield excavator 1 is advanced, and the inner seal 11 is left as it is in the ground outside the small diameter segment S2.

Thereafter, the tunnel T is constructed using the large-diameter segment S1, and the shield excavator 1
When a shaft (not shown) provided at the end point is reached, construction of the tunnel T having a predetermined length is completed.

In the above shield method, the segment S to be assembled is changed from the large-diameter segment S1 to the small-diameter segment S2.
First, after the shield excavator 1 is advanced by the shield jack 9, the inner seal 11 is arranged without fixing the inside of the skin plate 3, and the small-diameter segment S2 'for the joint portion is provided inside the inner seal 11. Is assembled and fixed to the inner seal 11, the shield excavator 1 is further advanced by the shield jack 9, and the outer seal 10 and the inner seal 11 are positioned in a double state. The tunnel T was constructed by assembling. Thus, in the narrow shield excavator 1, the large diameter segment S
Switching from 1 to the small-diameter segment S2 can be easily performed. In addition, at this time, the inner seal 1 is provided in front of the outer seal 10 in a state where the waterproofness is maintained.
Since the shield excavator 1 is moved forward after disposing the outer seal 1 and the outer seal 10 and the inner seal 11 are disposed inside and outside, the watertightness can always be maintained.

Conversely, when the segment S to be assembled is switched from the small-diameter segment S2 to the large-diameter segment S1, the inner seal 11 and the outer seal 10 which are located inside and outside are separated, and then the shield jack 9 is used to excavate the shield. The machine 1 is advanced to leave the inner seal 11 behind, and thereafter, the large-diameter segment S1
And a tunnel T is constructed. At this time, similarly to the above, the switching from the small diameter segment S2 to the large diameter segment S1 can be easily performed in the narrow shield excavator 1. Moreover, small diameter segment S
Since the shield excavator 1 is moved forward with the inner seal 11 left on the outer peripheral side of 2 to expose the outer seal 10, it is possible to maintain the water stoppage.

In this way, in the place G1 where the soil water pressure from the ground G is low, the inner seal 11 is attached, the small diameter segment S2 is assembled, the lining thickness of the tunnel T is reduced, and the soil from the ground G is reduced. At a location G2 where the water pressure is high, the large diameter segment S1 is assembled to increase the lining thickness of the tunnel T. Thus, the surrounding ground G
By changing the lining thickness of the tunnel T to be built in accordance with the earth pressure from, the tunnel T can be made economical without waste. In addition, since this can be realized with one shield excavator 1, the design and construction cost can be suppressed.

In the above embodiment, the tunnel T
The example used was to increase the lining thickness during the excavation and then reduce it again. However, even if the lining thickness is reduced or expanded only once, or is changed many times, the construction is performed in the same manner as above. By doing so, it goes without saying that a similar effect can be obtained. The configuration of each part of the shield excavator 1 is not limited as long as the inner seal 11 is attached, and the above configuration can be applied to any type of shield excavator. Furthermore, it is also possible to prepare inner seals 11 having a plurality of types of thicknesses and change the lining thickness of the tunnel T in more steps. In addition, the above method can be applied to a case where the diameter of the tunnel itself (the inner diameter is also changed) is changed instead of changing the lining thickness.

[0029]

As described above, according to the shield method according to the first aspect, the tunnel is constructed by assembling the large-diameter segments, and then the shield excavator is first advanced by the jack. After that, the inner seal member is arranged inside the skin plate without being fixed, and then the small-diameter segment is assembled inside the skin plate, and after the small-diameter segment and the inner seal member are integrally fixed, the shield excavator is moved forward. In this way, the outer seal member and the inner seal member are double-located inside and outside, and then a small diameter segment is assembled to build a tunnel. In this way, it is possible to easily switch from a large-diameter segment to a small-diameter segment in a narrow shield excavator. In addition, at this time, the inner seal member is arranged in front of the outer seal member in a state where water is stopped by the outer seal member, and thereafter, the shield excavator is advanced to arrange the outer seal member and the inner seal member inside and outside. As a result, it is possible to always maintain the water stoppage. Then, in a place where the soil water pressure from the surrounding ground is equal to or higher than a predetermined reference, a large diameter segment is assembled to construct a tunnel, and in a place where the soil water pressure is equal to or lower than a predetermined reference, By switching the segments assembled in this way to the smaller-diameter segments, the tunnel can be made lean and economical. Moreover, since this can be realized by one shield excavator, the design and construction cost can be suppressed.

According to the shield method according to the second aspect, the outer seal member is provided on the tail portion of the skin plate, and the inner seal member is removably mounted inside the outer seal member. Then, the inner seal member and the outer seal member are separated, and then the shield excavator is advanced to leave the inner seal member behind, and thereafter, a large-diameter segment is assembled to form a tunnel. It is constructed to build. In this way,
Switching from a small diameter segment to a large diameter segment can be easily performed in a narrow shield excavator. In addition, at this time, the shield excavator is advanced while the inner seal member is left on the outer peripheral side of the small-diameter segment to expose the outer seal member. Then, in a place where the soil water pressure from the surrounding ground is equal to or lower than a predetermined standard, a small-diameter segment is assembled to construct a tunnel, and in a place where the soil water pressure is equal to or lower than a predetermined standard, the above is described. By switching to larger diameter segments
The tunnel can be made economical without waste. Moreover, since this can be realized by one shield excavator, the design and construction cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an example of a shield excavator used in a shield method according to the present invention.

FIG. 2 is a view illustrating an example of the shield method, and is a process diagram illustrating a method of switching from a large-diameter segment to a small-diameter segment.

FIG. 3 is a process diagram showing a state following FIG. 2;

FIG. 4 is a view showing an example of the shield method, and is a process diagram showing a method of switching from a small-diameter segment to a large-diameter segment.

[Explanation of symbols]

 Reference Signs List 1 shield excavator 3 skin plate 9 shield jack (jack) 10 outer seal (outer seal member) 11 inner seal (inner seal member) S segment S1 large diameter segment (large diameter segment) S2 small diameter segment (small diameter segment) T tunnel

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshio Watanabe 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Shigeru Nishitake 1-1-1 Wadazakicho, Hyogo-ku, Hyogo-ku, Kobe-shi, Hyogo No. 1 Inside Mitsubishi Heavy Industries, Ltd.Kobe Shipyard (72) Inventor Fumihiko Ise 2-1-1, Araimachi, Takasago, Hyogo Prefecture Inside Mitsubishi Heavy Industries, Ltd. 1-1-1 Wadazakicho Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (56) References JP-A-8-42293 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21D 11 / 38,11 / 10

Claims (2)

(57) [Claims] 1. A skin plate provided with an outer seal member that is substantially cylindrical and has a tail portion that prevents intrusion of muddy water and earth and sand, while digging a ground in front with a shield excavator,
By assembling a large-diameter segment having substantially the same outer diameter as the inner diameter of the outer seal member, a tunnel is built on the rear side, and then, first, a jack provided on the shield excavator is already assembled. After the shield excavator is advanced by obtaining a reaction force from the large-diameter segment, an annular inner seal member having an inner diameter smaller than the skin plate is arranged inside the skin plate without being fixed. Then, inside the inner seal member, while assembling a small-diameter segment having an outer diameter substantially the same as the inner diameter thereof, and fixing the small-diameter segment and the inner seal member integrally, The shield excavator is advanced by obtaining a reaction force on the small-diameter segment, and the outer seal member and the inner seal member are moved inward and outward. And a state of being positioned in a double, thereafter, the shield method, characterized in that said gradually the while the shield excavator is excavating assemble the small-diameter segments on the inside of the inner seal member construction tunnels. 2. An outer seal member for preventing intrusion of muddy water and earth and sand is provided at a tail portion of a substantially cylindrical skin plate of a shield excavator, and an inner diameter smaller than the skin plate is provided inside the outer seal member. A small-diameter segment having an outer diameter that is substantially the same as the inner diameter of the inner seal member in the skin plate while digging the front ground with the shield excavator while the inner seal member having the Then, a tunnel is built on the rear side, and then, first, after separating the inner seal member and the outer seal member, the jack obtains a reaction force on the already assembled small diameter segment with the jack. The shield excavator is advanced to leave the inner seal member behind, and thereafter, the shield excavator is A shield method, wherein a tunnel is constructed by assembling a large-diameter segment having an outer diameter substantially equal to the inner diameter of the outer seal member of the skin plate inside the outer seal member while excavating.