JP5024228B2 - Widening method of shield tunnel - Google Patents

Description

  The present invention relates to a method for widening a shield tunnel for constructing a branching / merging portion of a tunnel.

There is a growing need to expand existing shield tunnels without excavation when building subway stations and underpasses and junctions.
For example, in Patent Document 1, a plurality of roof shield tunnels are excavated outside the shield tunnel so as to surround the shield tunnel, and a ring-shaped lining wall is constructed by joining these roof shield tunnels together. A method of forming a widened portion by excavating the inside is disclosed.
JP 2007-217911 A

However, the method described in Patent Document 1 has the following problems.
(1) If even one place thinner than the predetermined thickness exists in the ring-shaped covering body, the covering body may be damaged by the earth pressure acting on the covering body.
(2) Since the earth and sand in the lining body is excavated without supporting the ring-shaped lining wall from the inside, there is a possibility that the covering body is damaged and the ground is deformed.

  Accordingly, the present invention has been made in view of the above-described conventional problems, and a shield tunnel widening method capable of widening the tunnel without cutting while reliably preventing ground deformation. The purpose is to provide.

  In order to achieve the above object, the shield tunnel widening method of the present invention is a shield tunnel widening method in which a pipe roof is formed and supported by a plurality of steel pipes in advance around the portion to be widened when the shield tunnel is widened. Enlarging a part of the shield tunnel to construct a work area for inserting the steel pipe into the ground, and a plurality of the steel pipes so as to surround the planned widening part from the work area A steel pipe installation step for forming a pipe roof by inserting, and a support wall for excavating the widened portion from the inside of the shield tunnel at a predetermined interval in the longitudinal direction and supporting the pipe roof at the excavated portion A supporting wall construction step to construct, and excavating the widened portion between the supporting walls, and supporting the pipe roof at the excavated portion A first precursor installation step of installing the body, and removing the said support wall, characterized in that it comprises a second precursor installation step of installing a building frame on the removal the position (the first invention).

  According to the widening method of the shield tunnel according to the present invention, a part of the shield tunnel is enlarged to construct a wide work area, so that the work of inserting the steel pipe into the natural ground and the work of transporting the material are performed in parallel. Can do. Therefore, the widening operation can be performed efficiently.

  In addition, since the pipe roof is formed by surrounding the widened portion of the tunnel with a plurality of steel pipes, the earth pressure and water pressure of the natural ground act on the steel pipes. And while supporting these steel pipes with support walls, excavating the planned widening part between the support walls and installing the frame, it is possible to widen the tunnel without digging while reliably preventing deformation of the natural ground Can do. Furthermore, since the steel pipe is supported by the frame installed between the support walls, the support wall is removed and a new frame is installed at the removed site, so that it is possible to reliably prevent deformation of the natural ground. Therefore, the shield tunnel can be widened even in deep underground.

In this invention, it is good also as providing the water stop layer formation process which inject | pours a water stop material into the natural ground from the said steel pipe, and forms a water stop layer so that the said width-expansion plan part may be enclosed.
According to the method for widening a shield tunnel according to the present invention, the water blocking layer is formed so as to surround the site to be widened, so that groundwater cannot enter the site to be widened. Therefore, since groundwater springs can be prevented when excavating the site to be widened, excavation work can be performed safely and efficiently.

In the present invention, a water blocking material is injected into the planned widening portion, and a water blocking wall in a direction substantially orthogonal to the longitudinal direction is constructed so that the water flowing into the widened planned portion does not flow in the longitudinal direction. It is good as well.
According to the method for widening a shield tunnel according to the present invention, the planned widening portion is divided into a plurality of sections by providing a water blocking wall in the planned widening portion. That is, even if the groundwater enters a specific section of the site to be widened, since the water blocking wall is provided, the groundwater cannot enter the section adjacent to the section. Therefore, even if the groundwater enters the site to be widened, the influence can be limited to a specific section.

  By using the shield tunnel widening method of the present invention, a large space for widening the tunnel can be constructed in the ground without uncutting while reliably preventing ground deformation.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view showing a shield tunnel 1 according to the first embodiment of the present invention. As shown in FIG. 1, in the present embodiment, a case will be described in which a widened portion 2 for constructing a lamp shield is formed on the side of the shield tunnel 1 (the lower side of FIG. 1). The widened portion 2 is constructed so that the diameter gradually increases toward the point where the lamp shields meet.

  FIG. 2 is a diagram showing a state in which a part of the shield tunnel 1 is enlarged and the work area 3 is constructed. 3 and 4 are a longitudinal sectional view and a transverse sectional view of the working area 3, respectively.

As shown in FIGS. 2 to 4, a part of the shield tunnel 1 is enlarged by the enlargement shield method, and the work area 3 for performing the widening work is constructed. In the present embodiment, the steel pipe 4 to be inserted into the natural ground E is enlarged by a length that allows about two steel pipes 4 to be juxtaposed. In the present embodiment, the shield tunnel 1 having an inner diameter of 11 m is enlarged to construct a work area 3 having an inner diameter of 15 m and a length in the longitudinal direction of 10.2 m.
When constructing the work area 3, a water stop material is injected into the surrounding natural ground E to form a water stop wall 5 for preventing inflow of groundwater into the work area 3.

A platform 6 serving as a scaffold for work is constructed in the work area 3, and a propulsion device 7 for propelling the steel pipe 4 into the ground E is installed on the platform 6. The propulsion device 7 is installed at each of three locations, an upper stage, a middle stage, and a lower stage in the work area 3 so that the steel pipe 4 can be inserted in parallel at a plurality of places.
Since each propulsion device 7 is installed on the widened outer peripheral portion 3 a, a truck or the like for transporting materials for other work can pass through the central portion 3 b of the work area 3.

FIG. 5 is a perspective view showing a state in which the water blocking walls 9 and 10 are formed in the widened planned portion 8.
As shown in FIG. 5, a plurality of water blocking walls 9, 10 are formed in the planned widening portion 8. The water blocking wall 9 is provided at a predetermined interval in the longitudinal direction of the shield tunnel 1, and the water blocking wall 10 is provided at the end portion of the widening planned site 8 where the steel pipe 4 is to be reached. The water blocking walls 9 and 10 are formed so that a water blocking material is poured in the transverse direction and completely crosses the widened portion 8. The work for forming the water blocking walls 9 and 10 may be performed in parallel with the work for constructing the work area 3.
The thickness of the water stop wall 9 in the planned widening portion 8 was about 2 m, and the thickness of the water stop wall 5 around the work area 3 and the water stop wall 10 at the end portion was about 4 m.

  FIG. 6 is a cross-sectional view of FIG. As shown in FIG. 6, a housing 12 is installed on the inner periphery of the shield tunnel 1 on the side opposite to the planned widening portion 8.

FIG. 7 is a perspective view showing a state in which the pipe roof 11 is formed by inserting the steel pipe 4 into the natural ground E. FIG. 8, FIG. 9, and FIG. 10 are a B sectional view, a C sectional view, and a D sectional view of FIG. 7, respectively.
As shown in FIG. 7, the pipe roof 11 is formed by inserting a plurality of steel pipes 4 into the natural ground E.

The work of inserting the steel pipe 4 into the ground E is performed by extruding the steel pipe 4 placed on the propulsion device 7 with a jack or the like at a predetermined inclination angle. As shown in FIG. 8, the steel pipe 4 is inserted into the outer peripheral portion 3a so that the adjacent steel pipes 4 are in a substantially lattice shape only on one side of the outer peripheral portion 3a.
When one steel pipe 4 is inserted by a predetermined length, a new steel pipe 4 is joined and extended by welding or the like, and these steel pipes 4 are again inserted into the natural ground E by the propulsion device 7. This operation is repeated until the steel pipe 4 at the tip reaches the water blocking wall 10 at the end.

Since each steel pipe 4 is propelled outwardly so as to enclose the planned widening portion 8, adjacent steel pipes 4 are elliptically arranged in a substantially lattice shape near the center of the widening planned portion 8 as shown in FIG. 9. It is laid to form.
And as shown in FIG. 10, the adjacent steel pipes 4 are laid so that the adjacent steel pipes 4 may form an ellipse in the vicinity of the terminal portion of the planned widening portion 8. When the end surface on the front end side of the steel pipe 4 reaches the inside of the water blocking wall 10 at the terminal end of the widened portion 8, the propulsion operation is stopped.

FIG. 11 is a perspective view showing a state in which the water blocking layer 13 is formed so as to surround the pipe roof 11. FIG. 12 is an E cross-sectional view of FIG. 11. As shown in FIGS. 11 and 12, a pipe is formed so that a water stop material is injected from the steel pipe 4 into the natural ground E to surround the widened portion 8. A water blocking layer 13 (double hatched portion in FIGS. 11 and 12) is formed on the outer peripheral side of the roof 11. At this time, it forms so that the both ends of the longitudinal direction of the water stop layer 13 may overlap with the water stop walls 5 and 10 already formed in the natural ground E. Accordingly, the planned widening portion 8 is completely covered by the water blocking layer 13 and the water blocking walls 5 and 10, so that the groundwater does not flow into the widening planned portion 8.

After forming the water blocking layer 13, the presence or absence of water leakage into the shield tunnel 1 is confirmed. If there is water leakage, a water blocking material is again injected from the steel pipe 4 to stop the water leakage.
Moreover, when excavating the earth and sand of the site 8 to be widened, an internal support 14 is installed in the shield tunnel 1 so that the shield tunnel 1 is not crushed by the earth pressure of the ground E. The internal support work 14 is installed inside the housing 12.

  FIG. 13 is a perspective view showing a state in which the planned widening portion 8 is excavated in a trench shape and the RC temporary support wall 15 is constructed there. FIG. 14 is a cross-sectional view taken along the line F in FIG.

As shown in FIG. 13 and FIG. 14, the trench wide excavation site 8 is excavated from the shield tunnel 1 at a predetermined interval. In the present embodiment, the predetermined interval is 8 m and the trench excavation width is 3 m. A curved RC temporary support wall 15 (upper right hatched portion in FIGS. 13 and 14) is constructed so as to be in contact with the lower surface of the pipe roof 11 at a site where the earth and sand are removed by trench excavation. An internal support 16 is installed inside the RC temporary support wall 15.
When excavating the widened portion 8 existing between the RC temporary support walls 15 (described later), the pipe roof 11 is supported by the RC temporary support wall 15 to prevent ground deformation.

FIG. 15 is a perspective view showing a state in which the space between the RC temporary support walls 15 is excavated and the housing 17 is installed there. FIG. 16 is a G sectional view of FIG.
As shown in FIG.15 and FIG.16, the widening plan site | part 8 between RC temporary support walls 15 (the downward slanting oblique line part of FIG. 15) is excavated, earth and sand are removed, and the frame 17 is installed in this excavated site. Both ends in the circumferential direction of the newly installed casing 17 are connected to and integrated with both ends of the previously installed casing 12, respectively.
When the RC temporary support wall 15 is removed (described later), the pipe roof 11 is supported by the casing 17 to prevent ground deformation.

FIG. 17 is a perspective view showing a state where the RC temporary support wall 15 is removed and the housing 17 is installed therein.
As shown in FIG. 17, the RC temporary support wall 15 and the internal support work 16 are removed, and the housing 17 is installed there. Both ends of the casing 17 in the circumferential direction are connected to and integrated with both ends of the casing 12 installed in advance as described above.
18 is a cross-sectional view taken along the line H in FIG. As shown in FIG. 18, finally, the internal support work 14 is removed and the widening operation is completed.

Next, a second embodiment of the present invention will be described. In the following description, portions corresponding to the first embodiment are denoted by the same reference numerals, description thereof is omitted, and differences are mainly described.
In the second embodiment, the widened portion 18 is constructed on both sides of the shield tunnel 1.

FIG. 19 is a plan view showing a shield tunnel 1 according to the second embodiment of the present invention.
As shown in FIG. 19, in the present embodiment, a case will be described in which the widened portion 18 for constructing the lamp shield is formed on both sides of the shield tunnel 1 (upper and lower sides in FIG. 19).

FIG. 20 is a perspective view showing a state in which the water blocking walls 5, 20, and 21 are formed in the widening planned portion 19.
As shown in FIG. 20, first, as in the first embodiment, a part of the shield tunnel 1 is enlarged to construct the work area 3.
Next, a water-stopping material is injected from the inside of the shield tunnel 1 into the widened planned portions 19 on both sides at a predetermined interval to form a plurality of water-stop walls 20 and 21. The thickness of the water stop wall 20 in the planned widening portion 19 was about 2 m, and the thickness of the water stop wall 5 around the work area 3 and the water stop wall 21 at the end portion was about 4 m.

FIG. 21 is a perspective view showing a state in which the pipe roof 22 is formed by inserting the steel pipe 4 into the natural ground E. FIG. 22 and 23 are an I sectional view and a J sectional view of FIG. 21, respectively.
As shown in FIG. 21, the pipe roof 22 is formed by inserting a plurality of steel pipes 4 into the ground E from the work area 3.
The work of inserting the steel pipe 4 into the ground E is performed by pushing the steel pipe 4 placed on the propulsion device 7 in the work area 3 with a jack or the like at a predetermined inclination angle, as in the first embodiment. As shown in FIG. 22, the steel pipe 4 is inserted into the outer peripheral portion 3a of the work area 3 so that the adjacent steel pipes 4 have a substantially lattice shape.
Then, as shown in FIG. 23, adjacent steel pipes 4 are laid so as to form an ellipse in the vicinity of the end portion of the planned widening portion 19.

FIG. 24 is a perspective view showing a state in which the water blocking layer 23 is formed so as to surround the pipe roof 22. FIG. 25 is a K cross-sectional view of FIG.
As shown in FIGS. 24 and 25, a water-stopping material is injected from the inside of the steel pipe 4 into the natural ground E, and the water-stopping layer 23 (the double hatched portion in FIGS. ).
In addition, an internal support 14 is installed in the shield tunnel 1 so that the shield tunnel 1 is not crushed by earth pressure in the ground E.

FIG. 26 is a perspective view showing a state in which the planned widening portion 19 is excavated in a trench shape and the RC temporary support wall 24 is constructed there. FIG. 27 is an L sectional view of FIG.
As shown in FIG. 26 and FIG. 27, the trench widening portion 19 is trench excavated from the shield tunnel 1 at a predetermined interval. The RC temporary support wall 24 (the hatched portion on the upper right in FIGS. 26 and 27) is constructed so as to be in contact with the lower surface of the pipe roof 22 at the site where the earth and sand are removed by trench excavation. Two internal supporters 16 are installed inside the RC temporary support wall 24.

FIG. 28 is a perspective view showing a state where the space between the RC temporary support walls 24 is excavated and the housing 26 is installed there. FIG. 29 is a sectional view taken along line M in FIG.
As shown in FIG. 28 and FIG. 29, the widening planned portion 19 between the RC temporary support walls 24 (the downward slanted line portion in FIG. 28) is excavated to remove the earth and sand, and the frame 26 is installed in the excavated portion.

FIG. 30 is a perspective view showing a state in which the RC temporary support wall 24 and the internal support 16 are removed, and the housing 26 is installed there. FIG. 31 is a cross-sectional view taken along the line N in FIG.
As shown in FIGS. 30 and 31, the RC temporary support wall 24 and the internal support 16 installed inside the RC temporary support wall 24 are removed, and the housing 26 is installed there. Finally, the internal support 14 is attached. Remove and finish widening.

Next, a third embodiment of the present invention will be described. In the third embodiment, the widened portion 25 parallel to the shield tunnel 1 is constructed.
FIG. 32 is a perspective view of the shield tunnel 1 according to the third embodiment of the present invention.
As shown in FIG. 32, in this embodiment, a case where the widened portion 25 is constructed on the side of the shield tunnel 1 (the front side in FIG. 32) will be described.

First, a part of the shield tunnel 1 is enlarged to construct a work area 27 for performing widening work. The side of the work area 27 on the widened portion 25 side is enlarged so as to be the same as the diameter of the tunnel after widening.
Next, as in the first embodiment, a water-stopping material is injected from the inside of the shield tunnel 1 into the widened portion 28 to form a plurality of water-stop walls 29, 30, 31, and the inner periphery of the shield tunnel 1. The housing 12 and the internal support work 14 are installed.

  FIG. 33 is a perspective view showing a state in which the pipe roof 32 is formed by inserting the steel pipe 4 into the natural ground E. FIG. 34 and 35 are a P sectional view and a Q sectional view of FIG. 33, respectively.

  As shown in FIG. 33, the pipe roof 32 is formed by inserting a plurality of steel pipes 4 into the natural ground E. Moreover, as shown in FIG. 34, the steel pipe 4 is inserted into the outer peripheral portion 27a of the work area 27 so that the adjacent steel pipes 4 form an ellipse. Since the inserted steel pipe 4 is propelled in parallel with the shield tunnel 1, as shown in FIG. 35, adjacent steel pipes 4 form an ellipse in the vicinity of the end portion of the planned widening portion 28 as well as the insertion portion. is doing.

  Although not shown in the drawings, the work contents after this are not shown, but the water stop layer 13 is formed so as to cover the widened portion 28, and the widened portion 28 is trench-excavated for RC temporary support wall 15. In addition, after the internal support 16 is installed, the widening planned portion 28 between the RC temporary support walls 15 is excavated to install the housing 12. And the RC temporary support wall 15 and the internal support work 16 are removed, and simultaneously, the housing 12 is installed there, and finally the internal support work 14 is removed and the widening operation is completed.

  In the present embodiment, the case where the widened portion 25 is constructed on the side of the shield tunnel 1 (the front side in FIG. 32) has been described. However, the widened portion 25 is not limited to one side of the shield tunnel 1. Even when the widened portions 25 are provided on both sides of the shield tunnel 1, it can be applied by performing the same construction method as in the second embodiment.

  According to the widening method of the shield tunnel 1 in each embodiment described above, since the work areas 3 and 27 are constructed by enlarging a part of the shield tunnel 1, the steel pipe 4 is connected to the ground E by the outer peripheral portions 3a and 27a. The material can be transported at the central portions 3b and 27b. Therefore, the widening operation can be performed efficiently.

  In addition, since the pipe roofs 11, 22, and 32 are formed so as to surround the tunnel widening portions 8, 19, and 28 with the plurality of steel pipes 4, the earth pressure and water pressure of the natural ground E act on the steel pipes 4. And since these steel pipes 4 are supported by the RC temporary support walls 15 and 24 and the widening scheduled portions 8, 19 and 28 are excavated, the deformation of the natural ground E can be surely prevented. Further, while supporting the steel pipe 4 with the casings 17 and 26 installed between the RC temporary support walls 15 and 24, the RC temporary support walls 15 and 24 are removed, and new casings 17 and 26 are installed at the removed sites. Therefore, deformation of the natural ground E can be reliably prevented. Therefore, it is possible to widen the shield tunnel 1 even in a deep underground.

  Moreover, since the steel pipe 4 is always supported by either the RC temporary support walls 15 and 24 or the casings 17 and 26, the steel pipe 4 is not damaged or bent by earth pressure or water pressure. Therefore, it is possible to excavate the planned widening portions 8, 19, and 28 safely.

  Moreover, since the water blocking layers 13 and 23 and the water blocking walls 5, 10, 21, 29, and 31 are formed so as to surround the widening planned portions 8, 19, and 28, groundwater is placed in the widened planned portions 8, 19, and 28. It cannot be infiltrated. Therefore, since the groundwater spring during excavation of the planned widening portions 8, 19, and 28 can be prevented, the excavation work can be performed safely and efficiently.

  And the widening planned site | parts 8, 19, and 28 are divided | segmented into a some area by providing the several water stop walls 9, 20, and 30 in the widening plan site | parts 8, 19, and 28. FIG. That is, even if the groundwater enters the specific section of the planned widening parts 8, 19, and 28, the water blocking walls 9, 20, and 30 are provided, so that the groundwater can enter the section adjacent to the section. Can not. Therefore, even if the groundwater enters the widening planned sites 8, 19, and 28, the influence can be limited to a specific section.

It is a top view which shows the shield tunnel which concerns on 1st embodiment of this invention. It is a figure which shows the state which expanded a part of shield tunnel and constructed | assembled the work area. It is longitudinal direction sectional drawing of a working area. It is a cross-sectional view in the transverse direction of the work area. It is a perspective view which shows the state which formed the water stop wall in the site | part to which widening is planned. It is A sectional drawing of FIG. It is a perspective view which shows the state which laid the steel pipe in the natural ground and formed the pipe roof. It is B sectional drawing of FIG. It is C sectional drawing of FIG. It is D sectional drawing of FIG. It is a perspective view which shows the state which formed the water stop layer so that a pipe roof might be enclosed. It is E sectional drawing of FIG. It is a perspective view which shows the state which excavated the widening plan site | part in the shape of a trench, and constructed RC temporary support wall there. It is F sectional drawing of FIG. It is a perspective view which shows the state which excavated between RC temporary support walls, and installed the housing there. It is G sectional drawing of FIG. It is a perspective view which shows the state which removed the RC temporary support wall and installed the housing there. It is H sectional drawing of FIG. It is a top view which shows the shield tunnel which concerns on 2nd embodiment of this invention. It is a perspective view which shows the state which formed the water stop wall in the site | part to which widening is planned. It is a perspective view which shows the state which laid the steel pipe in the natural ground and formed the pipe roof. It is I sectional drawing of FIG. It is J sectional drawing of FIG. It is a perspective view which shows the state which formed the water stop layer so that a pipe roof might be enclosed. It is K sectional drawing of FIG. It is a perspective view which shows the state which excavated the widening plan site | part in the shape of a trench, and constructed RC temporary support wall there. It is L sectional drawing of FIG. It is a perspective view which shows the state which excavated between RC temporary support walls, and installed the housing there. It is M sectional drawing of FIG. It is a perspective view which shows the state which removed the RC temporary support wall and installed the housing there. It is N sectional drawing of FIG. It is a perspective view of the shield tunnel which concerns on 3rd embodiment of this invention. It is a perspective view which shows the state which laid the steel pipe in the natural ground and formed the pipe roof. It is P sectional drawing of FIG. It is Q sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shield tunnel 2 Widening part 3 Work area 3a Outer peripheral part 3b Central part 4 Steel pipe 5 Water stop wall 6 Mount 7 Propulsion device 8 Widening planned part 9 Water stop wall 10 Water stop wall 11 Pipe roof 12 Body 13 Water stop layer 14 Internal support Construction 15 RC temporary support wall 16 Internal support 17 Housing 18 Widened portion 19 Widened portion 20 Water stop wall 21 Water stop wall 22 Pipe roof 23 Water stop layer 24 RC temporary support wall 25 Widened portion 26 Housing 27 Work area 27a Outer peripheral portion 27b Central portion 28 Widened area 29 Water blocking wall 30 Water blocking wall 31 Water blocking wall 32 Pipe roof E Ground

Claims (3)

When widening the shield tunnel, in the widening method of the shield tunnel that supports the periphery of the site to be widened in advance with a pipe roof made of a plurality of steel pipes,
Enlarging a part of the shield tunnel, a work area construction process for constructing a work area for inserting the steel pipe into a natural ground,
Inserting a plurality of the steel pipes from the work area so as to enclose the planned widening part to form a pipe roof,
A support wall construction step of excavating the widened portion from the shield tunnel at a predetermined interval in the longitudinal direction and constructing a support wall for supporting the pipe roof at the excavated portion;
Excavating the planned widening portion between the support walls, and a first housing installation step of installing a housing for supporting the pipe roof at the excavated portion;
A shield tunnel widening method comprising: removing the support wall; and a second housing installation step of installing a housing at the removed location.   2. The shield tunnel according to claim 1, further comprising a water-stop layer forming step of injecting a water-stop material into the ground from the steel pipe to form the water-stop layer so as to surround the widened portion. Widening method.   A water blocking wall forming step for forming a water blocking wall for injecting a water blocking material from the shield tunnel to the site to be widened and restricting movement of water in the site to be widened in the longitudinal direction; The method for widening a shield tunnel according to claim 1 or 2, further comprising:

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