Methods for constructing retaining walls and underground structures
The diagonal member retaining wall structure addresses cross-sectional defects and cost issues in tunnel connections by installing diagonal members from inside tunnels with ground improvement, ensuring minimal excavation and soil stability.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TAISEI CORP
- Filing Date
- 2022-05-11
- Publication Date
- 2026-07-22
AI Technical Summary
Existing methods for connecting adjacent tunnels result in cross-sectional defects and increased manufacturing costs due to the need for special processing and larger excavation cross-sections, as well as potential soil collapse and groundwater inflow.
A retaining wall structure using diagonal members installed from inside the tunnels, intersecting above the gap, with ground improvement to prevent soil collapse and groundwater ingress, allowing for minimal excavation and no natural ground between tunnels.
Enables connection of tunnels without cross-sectional loss, maintaining minimal excavation and preventing soil collapse, while reducing manufacturing costs and equipment requirements.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a retaining structure between tunnels arranged side by side in the ground and a method for constructing an underground structure.
Background Art
[0002] In some cases, one underground structure is constructed using a plurality of tunnels arranged side by side. When constructing this underground structure, after constructing a plurality of tunnels, unnecessary lining of the tunnels is removed to form a large space, and the remaining lining of each tunnel is used to construct the top and bottom plates, side walls, etc. of the main installation. At this time, there may be a gap between adjacent tunnels. When connecting tunnels arranged side by side with a gap, it is necessary to prevent the collapse of earth and sand from above when excavating the ground between the tunnels.
[0003] As such a retaining structure, in some cases, a retaining is performed on the upper part of the area between the tunnels 110 by horizontally spanning a steel pipe 120 from one tunnel 110 to the other tunnel 110 by means of a so-called pipe roof method (see FIG. 10). Since the pipe roof method performs work from inside the tunnel 110, a retaining (steel pipe 120) is formed at a position lower than the upper end (lower surface of the top plate) of the tunnel, and the natural ground (remaining ground G R ) remains in the part above the retaining (steel pipe 120). Therefore, when constructing the lining of the underground structure using the lining of each tunnel 110, a large cross-sectional defect occurs in the lining of the underground structure at the joint between the tunnels 110. Therefore, as shown in Patent Document 1, the applicant has proposed a retaining structure for connecting two tunnels arranged side by side with a gap, in which a retaining steel plate is spanned from the upper and lower parts of one tunnel to the upper and lower parts of the other tunnel, and a water-stop injection material is injected above the retaining steel plate spanned on the upper part and below the retaining steel plate spanned on the lower part. However, in order to push (slide) the retaining steel plates from one tunnel to the other underground, special processing is required on the segments, such as processing to insert the press-in machine for sliding the retaining steel plates and processing to install the retaining steel plates in place on the segments, which increases the manufacturing cost of the segments. In addition, space must be secured above the tunnel to hold the retaining steel plates before they are slid, so the excavation cross-section must be larger than the design cross-section. [Prior art documents] [Patent Documents]
[0004] [Patent Document 1] Japanese Patent Publication No. 2002-115485 [Overview of the Initiative] [Problems that the invention aims to solve]
[0005] The objective of this invention is to propose a retaining wall structure and a method for constructing underground structures that can connect box-shaped structures placed side by side underground without leaving any natural ground between them. [Means for solving the problem]
[0006] To solve the aforementioned problems, the earth retention structure of the present invention is an earth retention structure formed above the region between a pair of adjacent tunnels spaced apart in the ground, and comprises a first diagonal member driven from the top of one tunnel toward the top of the other tunnel, and a second diagonal member driven from the top of the other tunnel toward the top of the first tunnel. The first and second diagonal members are driven starting from different tunnels, and the first and second diagonal members intersect above the region in a front view. The first diagonal member is inserted through a through hole provided in the ceiling of one tunnel and is driven in until it overlaps the other tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of one tunnel. The second diagonal member is inserted through a through hole provided in the ceiling of the other tunnel and is driven in until it overlaps the one tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of the other tunnel. ru. Furthermore, the method for constructing an underground structure of the present invention involves moving from the upper part of one of a pair of adjacent tunnels to the upper part of the other tunnel. Improved groundThe process of driving the first diagonal member toward and from the upper part of the other tunnel toward the upper part of the one tunnel Improved ground The method comprises the steps of: driving a second diagonal member toward the tunnel; excavating the area between the tunnels; and connecting the tunnels. The first diagonal member is driven into the ground by inserting it through a through hole provided in the ceiling of one tunnel and overlapping it with the other tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of one tunnel. The second diagonal member is driven into the ground by inserting it through a through hole provided in the ceiling of the other tunnel and overlapping it with the one tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of the other tunnel. The first and second diagonal members are cast starting from different tunnels and are arranged so as to intersect in a front view above the area.
[0007] According to this method of constructing earth retention structures and underground structures, by installing diagonal members from inside the tunnel, earth retention is formed at a position higher than the tunnel, making it possible to connect tunnels without leaving any natural ground between them. Therefore, even when constructing the lining of an underground structure using a tunnel, there is no cross-sectional loss in the lining of the underground structure, and the excavation cross-sectional area of the tunnel can be kept to the minimum necessary. In addition, the diagonal members can be installed from inside the tunnel using general equipment. Furthermore, by performing ground improvement work on the ground surrounding the first and second diagonal members, the collapse of soil and sand through the gaps between the first and second diagonal members can be suppressed. It is preferable to carry out such ground improvement work using the first and second diagonal members. [Effects of the Invention]
[0008] According to the present invention, the earth retention structure and underground structure construction method make it possible to connect tunnels that are laid side by side underground without leaving any natural ground between them. [Brief explanation of the drawing]
[0009] [Figure 1] This is a cross-sectional view showing an overview of the underground structure according to this embodiment. [Figure 2] This is a cross-sectional view showing the retaining wall structure. [Figure 3] This is a plan view of the retaining wall structure. [Figure 4] This flowchart shows the procedure for constructing the underground structure according to this embodiment. [Figure 5]This is a cross-sectional view showing the box formation process. [Figure 6] This is a cross-sectional view showing the ground improvement process. [Figure 7] This is a cross-sectional view showing the process of installing the first diagonal member. [Figure 8] This is a cross-sectional view showing the process of installing the second diagonal bracing member. [Figure 9] This is a cross-sectional view showing the excavation process. [Figure 10] This is a cross-sectional view showing an example of a conventional earth retention structure. [Modes for carrying out the invention]
[0010] In this embodiment, we will describe a case in which a large-section underground structure 1 is constructed by connecting a pair of box-shaped structures (tunnels) 2,2 that are laid side by side underground. Figure 1 shows an overview of the underground structure 1. Box bodies 2 are installed underground using methods such as shield tunneling or pipe jacking. Adjacent box bodies 2, 2 are installed side by side with a gap between them, as shown in Figure 1. The underground structure 1 is formed by excavating area A between the box bodies 2, removing unnecessary lining 21 facing area A, and installing new connecting linings 22, 23 above and below area A. The new linings 22, 23 are connected to the remaining lining 20. When excavating area A and removing unnecessary lining 21, a retaining wall structure 3 is formed above area A between the box bodies 2 to prevent soil collapse.
[0011] Figures 2 and 3 show the retaining wall structure 3. As shown in Figure 2, the retaining wall structure 3 includes a first diagonal member 4 extending from the top of one box body 2 (first box body 2a) to the top of the other box body 2 (second box body 2b), and a second diagonal member 5 extending from the top of the second box body 2b to the top of the first box body 2a. In addition, ground improvement Gi has been applied to the ground G surrounding the first diagonal member 4 and the second diagonal member 5. The first diagonal member 4 and the second diagonal member 5 intersect above region A in a front view (viewed in the tunnel axis direction). In this embodiment, the first diagonal member 4 and the second diagonal member 5 are made of steel pipes.
[0012] As shown in FIG. 3, a plurality of first diagonal members 4 are provided at predetermined intervals (for example, 1 m) along the axial direction of the first housing 2a. Further, the second diagonal members 5 are provided along the axial direction of the second housing 2b so as to be arranged at intermediate positions between the first diagonal members 4. That is, the first diagonal members 4 and the second diagonal members 5 are provided in plurality at the same intervals and alternately.
[0013] Next, a method for constructing the underground structure 1 will be described. FIG. 4 shows the procedure of the method for constructing the underground structure 1. As shown in FIG. 4, the method for constructing the underground structure 1 includes a housing forming step S1, a ground improvement step S2, a first diagonal member driving step S3, a second diagonal member driving step S4, an excavation step S5, and a connection step S6. As shown in FIG. 5, the housing forming step S1 is a step of forming a pair of adjacent housings 2, 2 at intervals. FIG. 5 is a cross-sectional view showing the housing forming step S1. The housing 2 is formed by the shield method or the propulsion method. The housing 2 of the present embodiment has a rectangular cross-section.
[0014] FIG. 6 shows the ground improvement step S2. As shown in FIG. 6, the ground improvement step S2 is a step of performing ground improvement Gi on the ground G above the region A between the housings 2. The ground improvement Gi is performed on the ground G around the planned driving positions of the first diagonal members 4 and the second diagonal members 5. In the present embodiment, chemical liquid injection is performed on the ground G from inside the housing.
[0015] The first diagonal member installation process S3 is the process of installing the first diagonal member 4 from the top of the first box structure 2a toward the top of the second box structure 2b. Figure 7 shows the first diagonal member installation process S3. As shown in Figure 7, the first diagonal member 4 is installed diagonally toward the ground using a small boring machine or the like installed on the ceiling of the first box structure 2a. The first diagonal member 4 is inserted into the ground G through a through hole provided on the ceiling of the first box structure 2a. A pipe 41 that is slightly larger than the first diagonal member 4 is attached to the through hole formed in the segment of the first box structure 2a. The pipe 41 is equipped with a water-stopping means such as a water-stopping valve or prepender for use during construction. The first diagonal member 4 is inserted until it overlaps the second box structure 2b by a predetermined length (e.g., 500 mm to 1000 mm) in a plan view, and the base end is fixed to the ceiling of the first box structure 2a.
[0016] The second diagonal member installation process S4 is the process of installing the second diagonal member 5 from the top of the second box casing 2b toward the top of the first box casing 2a. Figure 8 shows the second diagonal member installation process S4. As shown in Figure 8, the second diagonal member 5 is installed diagonally toward the ground using a small boring machine or the like installed on the ceiling of the second box casing 2b. The second diagonal member 5 is inserted into the ground G through a through hole provided on the ceiling of the second box casing 2b. A pipe 51 that is slightly larger than the second diagonal member 5 is attached to the through hole formed in the segment of the second box casing 2b. The pipe 51 is equipped with a water-stopping means such as a water-stopping valve or prepender for use during construction. The installation of the second diagonal member 5 may be carried out in parallel with the installation of the first diagonal member 4, or it may be carried out after the installation of the first diagonal member 4. The second diagonal member 5 is inserted into the first box 2a until it overlaps it by a predetermined length (for example, 500 mm to 1000 mm) in a plan view, and its base end is fixed to the ceiling of the second box 2b. Excavation process S5 is the process of excavating the area A between the box bodies 2. Figure 9 shows excavation process S5. In excavation process S5, unnecessary lining 21 (lining facing area A) of the box bodies 2 is removed, and the ground G in area A is excavated. The connection process S6 is the process of connecting the box bodies 2 together. In the connection process S6, new linings 22 and 23 are installed above and below area A and connected to the linings 20 of the first box body 2a and the second box body 2b, thereby forming an integrated underground structure 1 of the first box body 2a and the second box body 2b (see Figure 1).
[0017] According to the construction method of the retaining wall structure 3 and underground structure 1 of this embodiment, the retaining wall 3 can be formed at a position higher than the upper surface of the box bodies 2, 2 by installing diagonal members (first diagonal member 4, second diagonal member 5) from inside the box body 2. Therefore, the box bodies 2 can be connected to each other without leaving any natural ground between them. Consequently, even when constructing the lining of the underground structure 1 using the box bodies 2, no cross-sectional loss occurs in the lining of the underground structure 1, and the excavation cross-sectional area of the box bodies 2 can be kept to the minimum necessary. In other words, an internal space with a height equal to or greater than that of the box bodies 2 can be secured between the box bodies 2. Furthermore, since the diagonal members (first diagonal member 4, second diagonal member 5) can be installed from inside the box structure 2 using general equipment, there is no need to perform any special processing on the segments (lining 20) that make up the box structure 2.
[0018] Furthermore, by applying ground improvement Gi to the ground G above area A, it is possible to suppress soil collapse and prevent the inflow of groundwater, etc. Furthermore, by constructing the first diagonal member 4 and the second diagonal member 5 from steel pipes, the first diagonal member 4 and the second diagonal member 5 will bear the superimposed load, thereby more reliably suppressing soil collapse. In the portion of the first diagonal member 4 that overlaps with the first box 2a and the portion that overlaps with the second box 2b in a plan view, ground reaction force from the ground G (improved ground Gi) below the first diagonal member 4 can be expected, thus suppressing deformation of the first diagonal member 4 due to the superimposed load acting from above in region A. In the portion of the second diagonal member 5 that overlaps with the first box 2a and the portion that overlaps with the second box 2b in a plan view, ground reaction force from the ground G (improved ground Gi) below the second diagonal member 5 can be expected, thus suppressing deformation of the second diagonal member 5 due to the superimposed load acting from above in region A.
[0019] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and each of the above-mentioned components can be modified as appropriate without departing from the spirit of the present invention. For example, in the above embodiment, ground improvement Gi is performed, but ground improvement Gi may be performed only as needed. Furthermore, the ground improvement method is not limited to chemical injection, but may be appropriately determined according to the soil type, for example, by injecting solidifying agents. Furthermore, although the above embodiment described the case of connecting newly constructed box structures, the application of the earth retention structure 3 of the present invention is not limited to this. For example, the earth retention structure of the present invention may be applied when connecting a newly constructed tunnel that is installed alongside an existing tunnel, or when connecting adjacent existing tunnels. Furthermore, the cross-sectional shape of the tunnel is not limited to a rectangle. The first diagonal member 4 and the second diagonal member 5 may be provided in multiple layers. Furthermore, the materials that make up the first diagonal member 4 and the second diagonal member 5 are not limited and may be, for example, reinforcing bars or single pipes.
[0020] The first diagonal member 4 and the second diagonal member 5 may be cast adjacent to each other and fixed at the intersection. Alternatively, a beam that is continuous in the axial direction may be provided directly below the intersection of the first diagonal member 4 and the second diagonal member 5, thereby connecting multiple first diagonal members 4 and multiple second diagonal members 5 in three dimensions. Alternatively, a roof-like retaining wall structure may be formed by providing boards on multiple first diagonal members 4. Similarly, boards may be provided on multiple second diagonal members 5. In the above embodiment, a rectangular cross-section box 2 is formed, but the shape of the box 2 is not limited, and for example, it may have a circular cross-section. [Explanation of symbols]
[0021] 1 Underground structure 2 Box-shaped structure (tunnel) 20 Lining 21 Unnecessary lining 22,23 New lining construction 2a First box (one of the boxes) 2b Second box (the other box) 3 Yamatome structure 4 First diagonal member 5 Second diagonal Area A G territory Gi Improved Territory
Claims
1. A retaining wall structure formed above the area between two adjacent pairs of tunnels that are spaced apart and arranged side by side underground, The first diagonal member was cast from the top of one tunnel towards the top of the other tunnel, A second diagonal member is installed from the top of the other tunnel toward the top of the first tunnel, The first and second diagonal members are cast starting from different tunnels. The first diagonal member and the second diagonal member intersect above the region in a front view, The first diagonal member is inserted through a through hole provided in the ceiling of one of the tunnels, and is driven in until it overlaps the other tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of one of the tunnels. The shoring structure is characterized in that the second diagonal member is inserted through a through hole provided in the ceiling of the other tunnel, is driven into the ground until it overlaps the first tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of the other tunnel.
2. The retaining wall structure according to claim 1, characterized in that the ground surrounding the first and second diagonal members is improved ground that has been improved before the first and second diagonal members were installed.
3. The process involves driving a first diagonal member from the top of one of a pair of adjacent tunnels spaced apart, toward the improved ground above the other tunnel, A step of driving a second diagonal member from the upper part of the other tunnel toward the improved ground above the first tunnel, The process of excavating the area between the aforementioned tunnels, A method for constructing an underground structure, comprising the step of connecting the aforementioned tunnels together, The first diagonal member is inserted through a through hole provided in the ceiling of one tunnel and driven into the ground until it overlaps the other tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of one tunnel. The second diagonal member is inserted through a through hole provided in the ceiling of the other tunnel and driven into the ground until it overlaps the first tunnel by a predetermined length in a plan view, and its base end is fixed to the ceiling of the other tunnel. A method for constructing an underground structure, characterized in that the first diagonal member and the second diagonal member are cast starting from different tunnels and are arranged to intersect in a front view above the area.