JP2008255614A - Support structure of natural ground and support method of natural ground - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a support structure and a support method of the natural ground, capable of supporting an excavation expected part even under the ground of the deep depth. <P>SOLUTION: This support structure 1 supports the periphery of the excavation expected part 10 in advance when excavating the natural ground 8 between two shield tunnels 2 and 4, and has a circular arc-shaped bent pipe 16, a reinforcing steel material 26 arranged in this bent pipe 16, a solidifying material 30 filled in the bent pipe 16, the improved ground 8A of improving the ground around the bent pipe 16, and a support material 6 arranged in the natural ground 8 above and below the excavation expected part 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ground support structure that supports the surroundings of a site to be excavated in advance when excavating a natural ground between the shield tunnels in order to communicate two shield tunnels arranged side by side.

  The construction method of excavating the ground between two shield tunnels installed side by side is used for construction of subway station yard, underpass branching and confluence. Here, in order to support the ground between the shield tunnels when excavating the ground between the shield tunnels, a method is used in which a support member is passed from one shield tunnel to the other shield tunnel.

For example, in Patent Document 1, a steel pipe is installed in a circular arc shape above and below a site to be cut from one shield tunnel to the other shield tunnel, and a reinforcing material is inserted and installed in the steel pipe. A method for supporting a mountain is disclosed.
JP 2004-169474 A

  However, in the method described in Patent Document 1, in the deep underground, the loading load of the natural ground acting on the planned excavation site becomes large, so that the natural ground cannot be sufficiently supported only by the steel pipe and the reinforcing material. There was a problem. Therefore, it is conceivable that beams are installed above and below the shield tunnel, or pillars are installed on both sides of the planned excavation site to support the natural ground, but the beams and columns are located within the building limits. So I couldn't adopt it.

  Therefore, the present invention has been made in view of the conventional problems as described above, and provides a ground support structure and a support method capable of supporting a planned excavation site even in a deep underground. The purpose is to do.

In order to achieve the above-mentioned object, the ground support structure of the present invention is a ground support structure that supports the surroundings of the planned excavation site in advance when excavating the ground between two shield tunnels arranged side by side. And it is installed in a natural ground so as to surround the other shield tunnel from the inside of one shield tunnel, and both ends are provided with arc-shaped reinforcements fixed to the lining body of the one shield tunnel. (First invention).
According to the ground support structure of the present invention, the other shield tunnel and the part to be cut are surrounded by the arc-shaped reinforcing material, so that the load due to the natural ground is supported by the reinforcing material. Therefore, since the load of the ground which acts on the other shield tunnel and the planned cutting site is reduced, the load acting on the other shield tunnel and the planned cutting site is remarkably reduced as compared with the case where no reinforcing material is installed.

According to a second invention, in the first invention, the reinforcing material is a curved pipe, and the curved pipe is filled with a solidifying material.
According to the support structure of the natural ground according to the present invention, since the solidified material is filled in the curved pipe that is the reinforcing material, it is possible to support a larger load than when only the reinforcing material is installed in the natural ground. . Therefore, it is possible to support natural ground even in deep underground.

According to a third invention, in the first invention, the reinforcing material is a curved pipe, and an arcuate steel material further installed in the curved pipe so as to surround the other shield tunnel from within one shield tunnel is further provided. And the curved pipe is filled with a solidifying material.
According to the ground support structure of the present invention, the steel material is installed in the curved pipe as the reinforcing material and the solidified material is filled, so that a larger load can be supported. Therefore, it is possible to support natural ground even in deep underground.

According to a fourth invention, in any one of the first to third inventions, an improved body having improved ground is formed around the reinforcing material.
According to the support structure of the present invention, since the improved body having improved ground is formed around the reinforcing material, the groundwater cannot enter the inside surrounded by the reinforcing material. Therefore, since there is no outflow of groundwater when the part to be cut is cut, the cutting work can be performed safely and efficiently.

According to a fifth invention, in any one of the first to fourth inventions, the support material is the one shield tunnel inside the ground surrounded by the reinforcing material and above and below the planned excavation site. It is installed so that it may span over the said other shield tunnel.
According to the support structure of the present invention, since the support material is installed on the inner side surrounded by the reinforcing material, the size and thickness of the support material can be reduced. Therefore, the installation work of the support material becomes easy, the efficiency of the installation work is improved, and the construction period can be shortened. Moreover, since a small support material can be used, it becomes possible to ensure a wide architectural limit of the space constructed by connecting them.

According to a sixth aspect of the present invention, there is provided a method for supporting a natural ground, in which the ground around a site to be cut is supported in advance when the ground between two shield tunnels arranged side by side is opened. An arc-shaped curved pipe is installed so as to surround the other shield tunnel, and both ends of the curved pipe are fixed to the shield body of the one shield tunnel, and a ground improvement material is filled around the curved pipe. Forming an improved body, inserting a reinforcing steel material into the curved pipe, filling the curved pipe with a solidifying material, and inside the ground surrounded by the curved pipe and above and below the planned cutting site In addition, a support material is installed from the one shield tunnel to the other shield tunnel so as to support a natural ground around the planned excavation site.
According to the ground support method according to the present invention, the circumference of the planned excavation portion is supported by the arcuate curved pipe, the support material, etc., so that the space constructed by connecting the shield tunnels is reliably supported. be able to.

  By using the natural ground support structure and natural ground support method of the present invention, it is possible to safely excavate the planned excavation site even in a deep underground.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view showing shield tunnels arranged in parallel to which the present invention is applied. As shown in FIG. 1, a first shield tunnel 2 and a second shield tunnel 4 having a circular cross section smaller than the first shield tunnel 2 are arranged adjacent to each other. In this way, the part 10 to be cut between the shield tunnels 2 and 4 having two circular cross-sections arranged adjacent to each other is cut to connect the shield tunnels 2 and 4. In addition, the cross-sectional shape of each shield tunnel 2 and 4 is not limited to the perfect circle shape shown in figure, An elliptical thing may be sufficient.
On the inner peripheral surface of each shield tunnel 2, 4, a steel segment 12 of the same standard is assembled in an annular shape over the entire periphery to form a covering body.

FIG. 2 is a diagram showing a ground support structure to which the present invention is applied. In FIG. 2, the support structure 1 supports the periphery of the planned cutting site 10 in advance when the ground 8 between the two shield tunnels 2 and 4 is cut. The support structure 1 includes a curved pipe 16 which is an arc-shaped reinforcing material, a reinforcing steel material 26 installed in the curved pipe 16, a solidified material 30 filled in the curved pipe 16, and the curved pipe 16. Improved ground 8A improved around the ground, support material 6 installed in the ground 8 above and below the planned excavation site 10, a reinforcing steel material 28 installed in the support material 6, and a support material 6 is provided with solidified material 30 filled in 6 and improved ground 8B with improved ground around support material 6.
The curved pipe 16 is installed in the natural ground 8 so as to surround the second shield tunnel 4 from within the first shield tunnel 2.

3 is a view taken in the direction of arrow A in FIG. As shown in FIG. 3, the curved pipes 16 are installed at predetermined intervals in the longitudinal direction of the first shield tunnel 2, specifically, installed between the main beams 20 of the segment 12. In this embodiment, a steel pipe having a circular cross section is used as the curved pipe 16, and the segment 12 is made of steel having a width of 1.2 m, for example, and the main beam 20 is erected at intervals of 40 cm. Bent tubes 16 are provided between 20 at intervals of about 40 cm.
Both ends of the curved pipe 16 are fixed to the segment 12 of the first shield tunnel 2. Note that both ends of the bent pipe 16 may be rigidly joined to the segment 12, and the joining structure is not particularly limited, but is joined by welding or bolt joining, for example.

4 is a cross-sectional view taken along the line BB ′ of FIG. As shown in FIG. 4, a reinforcing steel material 26 is inserted and installed in the curved pipe 16, and both ends of the reinforcing steel material 26 are fixed to the segment 12 of the first shield tunnel 2. However, both ends of the reinforcing steel material 26 do not necessarily have to be joined to the segment 12. In this embodiment, H-shaped steel is used as the reinforcing steel material 26. Further, the bent pipe 16 is filled with a solidifying material 30 such as mortar or concrete, and the reinforcing steel material 26 is formed by the solidifying material 30. It is fixed.

  And the surroundings of the curved pipe 16 are filled with the ground improvement material, and the improved ground 8A is formed.

  As shown in FIG. 2, the support material 6 is spanned from the first shield tunnel 2 to the second shield tunnel 4 in the natural ground 8 above and below the planned excavation site 10. As shown in FIG. 3, the supporting members 6 are installed at predetermined intervals in the longitudinal direction of the first shield tunnels 2, 4. For example, the main beam 20 of the segment 12 is the same as the curved pipe 16. Installed between. In the present embodiment, a steel pipe having a circular cross section is used as the support member 6.

  FIG. 5 is a cross-sectional view taken along the line C-C ′ of FIG. 2. As shown in FIG. 5, a reinforcing steel material 28 is inserted and installed in the support material 6, and both ends of the reinforcing steel material 28 are fixed to the segments 12 of the shield tunnels 2 and 4, respectively. Note that both ends of the reinforcing steel material 28 may be rigidly joined to the segment 12 as in the case of the reinforcing steel material 26, and the joining structure is not particularly limited. In the present embodiment, H-shaped steel is used as the reinforcing steel material 28.

  The support material 6 is filled with a solidifying material 30 such as mortar or concrete, and the reinforcing steel material 28 is fixed by the solidifying material 30.

  And the surroundings of the support material 6 are filled with the ground improvement material, and the improved ground 8B is formed.

  Below, the construction method of this support structure is demonstrated according to a construction procedure.

FIG. 6 is a diagram showing a construction process of the support structure 1 according to the present invention.
First, as shown in FIG. 6A, the curved pipe 16 is installed in the ground 8 by a propulsion pipe excavator so as to surround the second shield tunnel 4 from the inside of the first shield tunnel 2.

  FIG. 7 is a diagram showing a drilling method using a propulsion pipe excavator. As shown in FIG. 7, the propulsion pipe excavator 18 is formed by attaching a small excavator 19 to the tip of a curved pipe 16 serving as a propulsion pipe, and is bent by a propulsion jack 22 provided in the first shield tunnel 2. The tube 16 is pushed out along a guide 24 having the same curved shape and propelled into an arc having a constant curvature. At the same time as the propulsion, the small excavator 19 attached to the tip of the curved pipe 16 excavates the earth and sand, and excavates while excavating the excavated earth and sand into the first shield tunnel 2 through the curved pipe 16. . In the illustrated embodiment, the propulsion pipe excavator 18 passes through the starting port 12a formed in the segment 12 provided in the lower part of the first shield tunnel 2 and the ground 8 8 to the side from the inside of the first shield tunnel 2. It starts toward the inside and reaches an opening which is an arrival port 12b formed in the segment 12 provided at the upper part of the first shield tunnel 2 while digging upward in an arc shape with a constant curvature. The bent pipe 16 is successively added along with the excavation, thereby connecting the start port 12a and the arrival port 12b in an arc shape, and in the ground 8 on the side of the first shield tunnel 2, It is installed so as to surround the second shield tunnel 4.

  Next, as shown in FIG. 6B, the ground 8 around the curved pipe 16 is improved. In the ground improvement work, a ground improvement injection pipe (not shown) is inserted into the curved pipe 16, and an improved material such as a freezing agent or cement milk is supplied to the injection pipe to form a plurality of curved pipes 16. This is discharged into the surrounding natural ground 8 through a discharge hole (not shown), and the portion along the curved pipe 16 is consolidated and improved to form the improved ground 8A.

  Then, the reinforcing steel material 26 is inserted and installed in the curved pipe 16. In the insertion operation of the reinforcing steel material 26, the reinforcing steel material 26 is inserted into the bent pipe 16 and both ends are fixed to the segment 12. Then, the curved tube 16 is filled with the solidifying material 30.

  In the present embodiment, the case where the reinforcing steel material 26 is installed in the curved pipe 16 and the solidified material 30 is filled has been described. However, when the ground 8 can be supported only by the curved pipe 16, the reinforcing steel material 26 is used for reinforcement. The steel material 26 and the solidified material 30 may be omitted, the solidified material 30 may be filled, and the reinforcing steel material 28 may be omitted.

Next, as shown in FIG.6 (c), the support material 6 is installed in the natural ground 8. As shown in FIG. The support pipe 6 made of a steel pipe curved in an arc shape from the first shield tunnel 2 to the second shield tunnel 4 is drilled into the ground 8 so as to protrude upward and downward from the planned excavation site 10 respectively. The machine 18 is used for the transfer in the same manner as described above.
Next, as shown in FIG. 6D, the ground 8 around the support material 6 is improved.
As in the above, the ground improvement work is performed by inserting a ground improvement injection pipe (not shown) into the support material 6, supplying the improvement material to the injection pipe, and discharging a plurality of discharges formed on the support material 6. It discharges in the surrounding natural ground 8 through a hole (not shown), and the part along the support material 6 is solidified and improved, and the improved ground 8B is formed.

  Then, the reinforcing steel material 28 is inserted and installed in the support material 6. In the operation of inserting the reinforcing steel material 28, the reinforcing steel material 28 is inserted into the support material 6 and both ends are fixed to the segment 12. Then, the solidifying material 30 is filled into the support material 6.

  Then, after the solidifying material 30 is solidified, as shown in FIG. 6 (e), the planned excavation site 10 is excavated to connect both shield tunnels 2, 4.

  In the present embodiment, the case where the reinforcing steel material 28 is installed in the support material 6 and the solidification material 30 is filled has been described. However, the natural ground 8 surrounded by the bent pipe 16 only by the support material 6. Can be omitted, the reinforcing steel material 28 and the solidifying material 30 may be omitted, or only the reinforcing steel material 28 may be omitted.

  In addition, in this embodiment, although the case where the curved pipe 16 and the support material 6 had a circular cross section was demonstrated, it is not limited to this cross-sectional shape, The shape (for example, taper part of a cross-section taper shape) , Triangles or trapezoids) or squares.

  In addition, in this embodiment, although the case where H-shaped steel was used as the steel materials 26 and 28 for reinforcement was demonstrated, it is not limited to H-shaped steel, I-type steel, a steel pipe, etc. may be used.

  As described above, according to the ground support structure 1 according to the present invention, the arc-shaped curved pipe 16 and the reinforcing steel material 26 surround the second shield tunnel 4 and the planned excavation site 10, so Is supported by the bent pipe 16 and the reinforcing steel material 26. Accordingly, the load of the ground 8 that acts on the second shield tunnel 4 and the planned cutting site 10 is reduced. Therefore, the load that acts on the second shield tunnel 4 and the planned cutting site 10 includes the curved pipe 16 and the reinforcing steel material 26. Compared to the case where no is installed, it is significantly reduced.

  Further, since the reinforcing steel material 26 is installed in the curved pipe 16 and the solidified material 30 is filled, a larger load than that in the case where only the curved pipe 16 is installed in the ground 8 is supported. Can do. Therefore, it is possible to support natural ground even in deep underground.

  And since the improvement ground 8A which improved the natural ground around the curved pipe 16 is formed, groundwater does not penetrate | invade into the inner side surrounded by the curved pipe 16. Therefore, since there is no outflow of ground water when the planned cutting site 10 is cut, the cutting operation can be performed safely and efficiently.

  Furthermore, since the support material 6 is installed on the inner side surrounded by the curved pipe 16, the size, thickness, and the like of the support material 6 can be reduced. Therefore, since the installation work of the support material 6 becomes easy, the efficiency of the installation work is improved and the construction period can be shortened. Moreover, since the small support material 6 can be used, it becomes possible to ensure widely the construction limit of the space constructed by connecting.

It is a figure which shows the parallel shield tunnel to which this invention is applied. It is a figure which shows the support structure of the natural ground to which this invention is applied. FIG. 3 is a view taken in the direction of arrow A in FIG. 2. FIG. 3 is a B-B ′ sectional view of FIG. 2. FIG. 3 is a C-C ′ sectional view of FIG. 2. It is a figure which shows the construction process of the support structure by this invention. It is a figure which shows the excavation method by a propulsion pipe excavator.

Explanation of symbols

2 First shield tunnel 4 Second shield tunnel 6 Support material 8 Ground 8A, 8B Improved ground 10 Planned excavation site 12 Segment 16 Curved pipe 18 Propulsion pipe excavator 19 Small excavator 20 Main girder 22 Propulsion jack 24 Guides 26, 28 Reinforcing steel 30 Solidified material

Claims (6)

It is a support structure of a natural ground that supports the surrounding of the site to be excavated in advance when excavating the natural ground between two shield tunnels arranged side by side,
It is installed in a natural ground so as to surround the other shield tunnel from the inside of one shield tunnel, and both ends thereof are provided with arc-shaped reinforcing members fixed to the lining body of the one shield tunnel. Support structure.   2. The ground support structure according to claim 1, wherein the reinforcing material is a curved pipe, and the curved pipe is filled with a solidifying material. The reinforcing material is a curved pipe, and further comprises an arc-shaped reinforcing steel material installed in the curved pipe so as to surround the other shield tunnel from within one shield tunnel,
The ground support structure according to claim 1, wherein the bent pipe is filled with a solidifying material.   The ground support structure according to any one of claims 1 to 3, wherein an improved body whose ground is improved is formed around the reinforcing material.   A support material is installed so as to span from the one shield tunnel to the other shield tunnel in the ground surrounded by the reinforcing material and above and below the planned excavation site. The support structure of the natural ground in any one of Claims 1-4 to do. In the method of supporting the natural ground, which supports the surrounding of the site to be excavated in advance when excavating the natural ground between the two shield tunnels arranged side by side,
Installing an arc-shaped curved pipe so as to surround the other shield tunnel from within one shield tunnel, fixing both ends of the curved pipe to the lining body of the one shield tunnel,
Filling the ground improvement material around the curved pipe to form an improved body,
Inserting a reinforcing steel material into the curved pipe,
Filling the curved pipe with a solidifying material,
Inside the curved pipe and in the ground above and below the planned excavation site, installed so as to span the support material from the one shield tunnel to the other shield tunnel,
A method for supporting a natural ground, comprising supporting a natural ground around the planned excavation site.

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