Joint structure

Abstract

To provide a joint structure that can join bodies together to enable shear transmission, and then release the connection to make it a structure without shear transmission function. [Solution] A joint structure 3 includes a wall 23, an existing tunnel 11 that penetrates the wall 23, and a temporary shear key 4 that connects the wall 23 and the existing tunnel 11. The temporary shear key 4 has a cylindrical body 41 fixed to the wall 23 and a stiffener 43 inserted into the cylindrical body 41. The cylindrical body 41 opens to the inner surface of the tunnel, and the stiffener 43 can be removed from the cylindrical body 41 to the interior of the existing tunnel 11.

Description

[Technical Field]

[0001] The present invention relates to a joint structure between a wall and a tunnel. [Background technology]

[0002] At the junctions of road tunnels and at railway tunnel stations, widened sections that are wider than normal main line tunnels may be formed. Patent Document 1 discloses a construction method for widening a tunnel by forming a cylindrical outer shell using multiple small-section tunnels arranged in parallel to surround the main line tunnel, and then excavating the inside of the shell to form a widened section.

[0003] Small-section tunnels are excavated from a starting base formed at the boundary between the general section and the widened section. Patent Document 2 discloses a construction method for a starting base in which a radial space is formed from an existing tunnel in a direction perpendicular to the tunnel axis, and then a cylindrical outer shell is formed surrounding the existing tunnel by constructing multiple ring tunnels formed by the jacking method from the side walls of this radial space, and the area surrounded by the cylindrical outer shell is excavated and an earth retaining wall (side wall) is formed. The existing tunnel penetrates the earth retaining wall. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-105513 [Patent Document 2] Patent No. 6105028 Summary of the Invention [Problem to be solved by the invention]

[0005] Retaining walls are constructed while fixed to the existing tunnel so that they can transmit loads such as soil and water pressure to the existing tunnel. The most common method of fixing the two structures (retaining wall and existing tunnel) together is to embed steel materials that act as shear keys. However, if the existing tunnel and retaining wall are rigidly connected, displacement in the axial direction of the tunnel is restricted, which may make it difficult to ensure earthquake resistance. Earthquake resistance can be improved if the structure allows relative displacement between the tunnel and wall in the axial direction (a structure that makes it difficult for shear forces to be transmitted between the tunnel and wall). Therefore, the connection between the two structures must be released upon completion. However, it is difficult to remove shear keys (steel materials) that are embedded directly in the concrete.

[0006] The present invention aims to provide a joint structure that allows bodies to be joined together to enable shear transmission, and then the connection can be released to create a structure that does not have shear transmission function. [Means for solving the problem]

[0007] The present invention for solving the above problem provides a joint structure including a wall body, a tunnel penetrating the wall body, and a temporary shear key connecting the wall body and the tunnel, the temporary shear key including a cylindrical body fixed to the wall body and a shear key inserted into the cylindrical body. Made of steel rods Stiffeners and a support fixed to the tunnel lining; and a cylindrical socket fixed to the support so as to communicate with the cylindrical body. The cylindrical body has By communicating with the through-hole formed in the lining The stiffener is open to the inner surface of the tunnel. The cylindrical socket is fixed to the cylindrical socket, and when the cylindrical socket is removed from the cradle, The joining structure is such that the cylindrical body can be removed into the inner space of the tunnel.

[0008] In such a joint structure, if the stiffener is pulled out from the cylinder, only the sheath tube with low rigidity and strength remains at the joint between the wall and the tunnel, which allows the tunnel and the wall to displace relative to each other in the axial direction, resulting in a structure that has no shear transmission function during an earthquake. [Effects of the Invention]

[0009] According to the joint structure of the present invention, after joining the frames together so that shear transfer is possible, the connection can be released to create a structure that does not have the shear transfer function. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a cross-sectional view showing the tunnel widening portion of the present embodiment. [Figure 2] FIG. 2 is a longitudinal cross-sectional view showing a part of the tunnel widening section. [Figure 3] FIG. [Figure 4] 4A and 4B are diagrams showing a joint structure, in which (a) is a cross-sectional view taken along line IVA-IVA in FIG. 3, and (b) is a cross-sectional view taken along line IVB-IVB in (a). [Figure 5] This is a cross-sectional view showing the construction status of the circular tunnel. [Figure 6] 1A and 1B are diagrams showing a water-stopping structure, in which (a) is a longitudinal section and (b) is a cross-sectional view taken along the line VIB-VIB of (a). DETAILED DESCRIPTION OF THE INVENTION

[0011] In this embodiment, we will explain the joint structure between the wall and the tunnel involved in the construction of a tunnel widening section. Figures 1 and 2 show a tunnel widening section 1. As shown in Figures 1 and 2, the tunnel widening section 1 of this embodiment is formed by excavating the inside of a cylindrical outer shell 13 formed by multiple small-section tunnels 12, 12, ... arranged in parallel around an existing tunnel 11.

[0012] The small-section tunnel 12 is excavated from a starting base 2 formed at the end of the tunnel widening section 1. The starting base 2 has a cylindrical outer shell 22 formed by multiple circular tunnels 21, 21 surrounding the existing tunnel 11, and a wall 23 formed to shield the end face of the cylindrical outer shell 22. The existing tunnel 11 passes through the wall 23.

[0013] As shown in Figure 2, the joint structure 3 comprises a wall 23, an existing tunnel 11 penetrating the wall 23, a temporary shear key 4 connecting the wall 23 and the existing tunnel 11, and a support 5 fixed to the inner surface of the lining of the existing tunnel 11 (see Figures 3 and 4(a)).

[0014] 3 and 4 show a joint structure 3 between an existing tunnel 11 and a wall 23. As shown in FIGS. 4(a) and 4(b), the support 5 is made of a steel plate with a predetermined thickness and is fixed to the lining main girder 14 (the inner surface of the skin plate 15) of the existing tunnel 11 corresponding to the installation position of the temporary shear key 4. In this embodiment, the support 5 is rectangular. A mounting hole 51 with a female thread formed on the inner surface penetrates the support 5 according to the installation position of the temporary shear key 4. In this embodiment, two mounting holes 51 are formed at an interval in the tunnel axial direction. In addition, the support 5 is formed with multiple screw holes 52 that open toward the interior of the existing tunnel 11. The multiple screw holes 52 are formed along the periphery of the support 5. In other words, the multiple screw holes 52 are formed to surround the two mounting holes 51. It should be noted that there is no limitation on the number of mounting holes 51 formed in the receiving base 5. Furthermore, there is no limitation on the number and arrangement of the screw holes 52.

[0015] The temporary shear key 4 is a temporary shear resistance member for preventing misalignment between the existing tunnel 11 and the wall body 23 under construction, and comprises a cylindrical body 41, a cylindrical socket 42, and a stiffener 43. As shown in FIG. 3 , the cylindrical body 41 (temporary shear key 4) protrudes from the outer surface of the existing tunnel 11 and is fixed to the wall body 23. The cylindrical body 41 is composed of a pipe fixed to the outer surface of the lining (skin plate 15) of the existing tunnel 11 and opens to the inner surface of the existing tunnel 11. A through hole is formed in the skin plate 15 according to the installation location of the temporary shear key 4. The cylindrical body 41 opens to the inner surface of the existing tunnel 11 by communicating with the through hole in the skin plate 15. A flange 44 is formed at the base end of the cylindrical body 41, and the flange 44 abuts around the through hole and is fixed (e.g., welded) to the skin plate 15. In addition, spiral reinforcement 45 is provided around the cylindrical body 41 of this embodiment. The spiral reinforcement 45 is installed as needed. The flange 44 of the cylindrical body 41 may also be formed as needed.

[0016] The cylindrical socket 42 is a cylindrical member provided to communicate with the cylindrical body 41, and is attached to the lining of the existing tunnel 11 via the receiving base 5. A male thread is formed on the outer surface of the cylindrical socket 42. The cylindrical socket 42 is fixed to the receiving base 5 by screwing into a mounting hole 51 in the receiving base 5. The cylindrical socket 42 also has a plurality of (three in this embodiment) screw holes arranged at equal intervals around the circumference. Set screws 46 are screwed into the screw holes. The tips of the set screws 46 protrude into the interior space of the cylindrical socket 42.

[0017] The stiffener 43 is inserted into the cylindrical body 41. In this embodiment, the stiffener 43 is made of a steel rod. The base end of the stiffener 43 is fixed to the cylindrical socket 42. A plurality of screw holes are formed in the base end of the stiffener 43. The stiffener 43 is fixed to the cylindrical socket 42 by inserting it into the cylindrical socket 42 and threading a plurality of set screws 46, 46, 46 that pass through the cylindrical socket 42 into the screw holes in the stiffener 43. The stiffener 43 can be removed from the cylindrical body 41 to the interior of the existing tunnel 11. That is, the stiffener 43 can be removed together with the cylindrical socket 42 by rotating the cylindrical socket 42 and removing it from the receiving base 5.

[0018] The construction of the tunnel widening section 1 involves first forming a radial space (vertical shaft 16) from the existing tunnel 11 in a direction perpendicular to the tunnel axis, and then forming a plurality of annular tunnels 21 from the side walls of the vertical shaft 16 using a jacking method in the tunnel axis direction of the existing tunnel 11, thereby forming a cylindrical outer shell 22 surrounding the existing tunnel 11 (see Figure 5). Figure 5 is a cross-sectional view showing the construction status of the annular tunnel 21.

[0019] Next, the area surrounded by the cylindrical outer shell 22 is excavated and a wall 23 (side wall) is formed to construct the launch base 2 (see Figures 1 and 2). The wall 23 is formed while enclosing the existing tunnel 11. Temporary shear keys 4 are provided in the existing tunnel 11 (see Figure 3) and are fixed to the wall 23. Multiple temporary shear keys 4 are provided around the circumference of the existing tunnel 11. When constructing the wall 23, stiffeners 43 are inserted into the cylindrical bodies 41 of the temporary shear keys 4.

[0020] Once construction of the wall body 23 is complete, the cylindrical socket 42 is rotated and removed from the receiving base 5. Once the cylindrical socket 42 has been removed from the receiving base 5, the stiffener 43 is extracted from the cylindrical body 41 toward the interior of the existing tunnel 11. By removing the stiffener 43, only the cylindrical body 41, which has low rigidity and strength, remains, resulting in a joint structure that does not have the ability to transfer shear during an earthquake (see Figure 6). Figure 6 shows the joint structure 3 (waterstop structure) with the stiffener 43 removed.

[0021] After removing the stiffener 43, the cover material 6 is fixed to the receiving base 5 as shown in FIG. 6. The cover material 6 is fixed by passing a mounting screw 61 through the cover material 6 and screwing it into the screw hole 52 of the receiving base 5. At this time, a water-stopping material 62 is interposed between the receiving base 5 and the cover material 6. The water-stopping material 62 is arranged so as to surround the periphery of the mounting hole 51. This prevents groundwater and the like from flowing into the existing tunnel 11 through the mounting hole 51. In this embodiment, a water-stopping sealant is used as the water-stopping material 62. Note that the material constituting the water-stopping material 62 is not limited.

[0022] According to the joint structure 3 of this embodiment, when the wall body 23 is constructed, the stiffeners 43 are inserted into the cylindrical bodies 41, which enables shear transfer between the wall body 23 and the existing tunnel 11 via the shear reinforcement structure. On the other hand, when the stiffeners 43 are pulled out after the wall body 23 is completed, only the cylindrical bodies 41, which have low rigidity and strength, remain at the joint between the wall body 23 and the existing tunnel 11, which allows relative displacement between the existing tunnel 11 and the wall body 23 in the axial direction, resulting in a structure that does not have a shear transfer function during an earthquake.

[0023] The stiffener 43 is attached via the cylindrical socket 42 without the need for welding, bolts, or the like, making it easy to attach and detach. That is, the stiffener 43 can be removed by removing the cylindrical socket 42 from the support 5 and pulling the cylindrical socket 42 toward the interior of the existing tunnel 11. This makes the removal process easy. Furthermore, because no load is applied to the stiffener 43 when it is attached or detached, the stiffener 43 does not deform.

[0024] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and each of the above-described components can be appropriately modified within the scope of the invention. For example, in the above embodiment, the case of joining the wall 23 in the tunnel widening section 1 to the existing tunnel 11 was described, but the location of use of the joining structure 3 is not limited to the joint between the tunnel and the wall, and the use of the underground structure to be constructed is not limited.

[0025] The method for fixing the stiffener 43 is not limited to the fixing method using the cylindrical socket 42. For example, the stiffener 43 may be threaded and screwed into the mounting hole 51 of the receiving base 5. Furthermore, the method for removing the cylindrical socket 42 and the stiffener 43 is not limited to the method described in the above embodiment. For example, the set screw 46 may be removed, and only the stiffener 43 may be pulled out from the cylindrical body 41, and then the cylindrical socket 42 may be rotated and removed from the receiving base 5. [Explanation of symbols]

[0026] 1 Tunnel widening section 11 Existing tunnels 12 Small cross-section tunnel 13 Outer shell 14 Lining main girder 15 Skin Plate 2 Launch base 21 Circular Tunnel 22 Cylindrical outer shell 23 Wall 3 Joint structure 4 Temporary shear keys 41 Cylinder 42 Cylindrical socket 43 Stiffener 44 flange 45 Spiral Muscle 46 retaining screw 5 Receiving stand 51 Mounting hole 52 screw holes

Claims

[Claim 1] The wall and a tunnel penetrating the wall; A joint structure including a temporary shear key connecting the wall body and the tunnel, The temporary shear key has a cylindrical body fixed to the wall, a stiffener made of a steel rod inserted into the cylindrical body, a support base fixed to the lining of the tunnel, and a cylindrical socket fixed to the support base so as to communicate with the cylindrical body, The cylindrical body is connected to a through hole formed in the lining and opens to the inner surface of the tunnel, A joint structure characterized in that the stiffener is fixed to the cylindrical socket and can be removed from the cylindrical body to the interior of the tunnel when the cylindrical socket is removed from the support base.

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