Water stop structure between tunnels, water stop sheet, and method for constructing large cross-section tunnel

Abstract

To provide an inter-tunnel cut-off structure, a cut-off sheet, and a construction method for a large-section tunnel, which can be easily and surely constructed.SOLUTION: This water cut-off structure 3 between the tunnels is provided with a water cut-off sheet 4 arranged astride the adjacent box bodies 2, and a pressing tool 5 for holding an end part of the water cut-off sheet 4, and this construction method of the large cross section tunnel 1 uses this water cut-off structure 3 between the tunnels. A thickened part 44 is formed at the end of the water stop sheet 4 by providing a core material 42. A locking part 52 is formed at the end of the pressing tool 5, and the pressing tool 5 presses the water stop sheet 4 at the position of the core material 42 and holds the end of the water stop sheet 4 in a state of being locked to the thickened part 44 by the locking part 52.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a watertight structure between tunnels, a watertight sheet, and a method for constructing a large-section tunnel when connecting multiple parallel small-section tunnels to construct a large-section tunnel. [Background technology]

[0002] As a method for constructing a large cross-section tunnel underground, for example, as shown in Patent Document 1, there is a case where a large cross-section tunnel is formed by joining a plurality of small cross-section tunnels (box bodies) arranged side by side, either vertically or horizontally. Small tunnels are constructed by installing rectangular steel shells underground using either the jacking or shield tunneling methods. When constructing a large tunnel, the parts of adjacent small tunnels that are related to the structure of the large tunnel are integrated, and the parts of the small tunnels that are not related to the structure of the large tunnel are removed.

[0003] Depending on the tunnel construction method, tunnel alignment, and ground conditions, gaps may be left between adjacent small tunnels. For example, when constructing a small tunnel using the shield method, gaps are inevitably formed between the small tunnels due to the construction method in which segments (boxes) assembled inside the shield machine are placed underground. Therefore, when joining small tunnels, it is necessary to excavate the gaps between the small tunnels and install earth retaining structures to prevent the ground facing the gaps from collapsing.

[0004] A known structure for earth retaining at the junctions of small tunnels is to suspend steel earth retaining plates between the tunnels. Laying the steel earth retaining plates requires manual excavation of the surrounding ground, which is time-consuming. Therefore, Patent Document 2 discloses a construction method in which an earth retaining steel plate is slid from one small tunnel to the other, suspending the steel earth retaining plate horizontally between the tunnels to form an earth retaining, and then injecting a water-stop material into the ground facing the steel earth retaining plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-250957 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-115485 Summary of the Invention [Problem to be solved by the invention]

[0006] In the construction method of Patent Document 2, in order to slide a retaining steel plate from one small cross-section tunnel to the other small cross-section tunnel, it is necessary to excavate the ground in the area corresponding to the retaining steel plate on the other small cross-section tunnel side, which is a time-consuming task. The present invention aims to propose a method for constructing a watertight structure between tunnels, a watertight sheet, and a large-section tunnel that can be constructed easily and reliably. [Means for solving the problem]

[0007] The inter-tunnel watertight structure of the present invention, which solves the above-mentioned problems, includes a watertight sheet disposed across adjacent box bodies (small-section tunnels) and a clamp that holds the end of the watertight sheet. The end of the watertight sheet has a thickened portion formed thereon. The clamp presses the watertight sheet at the position of the thickened portion and holds the end of the watertight sheet in a state where it is engaged with the thickened portion by a locking portion formed at the end of the clamp.

[0008] It is desirable to use a waterproof sheet that comprises a waterproof sheet body and a core material provided at the end of the waterproof sheet body. It is preferable that the end of the waterproof sheet body is folded back around the core material as an axis, and the overlapping portion formed by folding back is glued or welded.

[0009] This inter-tunnel watertight structure allows for easy and reliable installation, as the watertight sheet is fixed to the box body with a simple structure that uses clamping fixtures to hold it down. Furthermore, the watertight sheet adheres tightly to the outer surface of the box body while being pressed against it, providing excellent watertightness. Furthermore, the watertight sheet is held in place with its thickened portion engaged with the clamping fixtures, preventing it from slipping out due to external pressure such as soil pressure or water pressure. Furthermore, the watertight sheet can be fixed without drilling holes.

[0010] If an internal support is provided inside the box body corresponding to the position of the clamp, the clamp can be fixed to the box body by fixing a fixing member (e.g., a bolt) that passes through the clamp and the box body to the internal support. If the ends of the waterproof sheet are fixed to the corners of the opposing surfaces of the adjacent boxes, the waterproof sheet can be installed without excavating the ground on the outer surface of the boxes. In this case, if arch-shaped support members are attached to the waterproof sheet and are placed horizontally across the adjacent boxes, the waterproof sheet's resistance to external pressure such as earth pressure and water pressure will increase.

[0011] The large-diameter tunnel construction method of the present invention includes a small-diameter tunnel construction process for forming adjacent box bodies at intervals, an inter-box excavation process for excavating the space between the adjacent box bodies, a watertightness process for sealing off water between the adjacent box bodies using the inter-tunnel watertight structure, and a joining process for joining the adjacent box bodies. The box bodies are formed by connecting multiple steel shells in the axial direction using a shield tunneling method or a jacking method. In the watertightness process, the watertight sheet is installed across the adjacent box bodies. Furthermore, in the joining process, the adjacent box bodies are joined and unnecessary members provided on the portions of the box bodies facing the other box bodies are removed.

[0012] According to this large-section tunnel construction method, a large-section tunnel made by joining a plurality of small-section tunnels (box bodies) arranged side by side can be constructed easily and reliably. Furthermore, if a caulking process is further provided before the water-stopping process, in which the joints between the adjacent steel shells are caulked to smooth the contact surfaces with the water-stop sheet at the joints, gaps are less likely to occur at the contact surfaces with the water-stop sheet, thereby improving water-stopping performance. [Effects of the Invention]

[0013] The watertight sheet, inter-tunnel watertight structure, and method for constructing a large-section tunnel of the present invention make it possible to easily and reliably construct a large-section tunnel by joining small-section tunnels together. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a front view showing the large cross-section tunnel of this embodiment. [Figure 2] FIG. 1 is a perspective view showing a water-stopping structure between tunnels. [Figure 3] FIG. 2 is a perspective view showing a waterproof sheet. [Figure 4] 1 is a flowchart showing the steps of a large cross-section tunnel construction method according to an embodiment of the present invention. [Figure 5] FIG. 10 is a front view showing the small-section tunnel construction process. [Figure 6] FIG. 10 is a front view showing the inter-box excavation process. [Figure 7] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] In this embodiment, a case where a large-diameter tunnel 1 is constructed by joining multiple small-diameter tunnels (box bodies 2) arranged side by side is described. FIG. 1 shows the large-diameter tunnel 1. The box bodies 2 are formed by connecting steel shells 21, each rectangular in cross section, in the axial direction. As shown in FIG. 1, the large-diameter tunnel 1 is formed by excavating the gaps 10 between multiple (four in this embodiment) box bodies 2 arranged side by side vertically and horizontally at intervals (gaps 10), integrating the portions (remaining portions 22) of the box bodies 2 (steel shells 21) that are related to the structure of the large-diameter tunnel 1, and pouring lining concrete 11. Thereafter, the portions (removed portions 23) of the box bodies 2 (steel shells 21) that are not related to the structure of the large-diameter tunnel 1 are removed.

[0016] In order to prevent groundwater and soil from flowing in from the natural ground G exposed by excavation into the gaps 10 between the box bodies 2, an inter-tunnel watertight structure 3 is formed on the outer surface (portion facing the natural ground G) of the gaps 10 (cut-out portion) between the box bodies 2. The inter-tunnel watertight structure 3 is formed in the gaps 10 between the box bodies 2 facing the outer periphery of the large-section tunnel 1.

[0017] 2 shows the inter-tunnel water stop structure 3. As shown in FIG. 2, the inter-tunnel water stop structure 3 includes a water stop sheet 4, a retainer 5, an internal support 6, and a support member 7. The waterstop sheet 4 is disposed across adjacent box bodies 2. Figure 3 shows the waterstop sheet 4. The waterstop sheet 4 comprises a waterstop sheet main body 41, a multilayered sheet consisting of a pair of synthetic rubber sheets sandwiching a reinforcing canvas, and a core material 42, a synthetic rubber rod attached to the end of the waterstop sheet main body 41. In this embodiment, a roll or long sheet is used for the waterstop sheet main body 41. The short-side end 43 of the waterstop sheet main body 41 is folded back around the core material 42, which is disposed along the tunnel axis, and the overlapping portion formed by the folding back is glued or welded. By folding the synthetic rubber sheet so as to wrap around the synthetic rubber rod (core material 42), a thickened portion 44 is formed at the end of the waterstop sheet 4. The structure of the waterstop sheet main body 41 is not limited, and it does not necessarily have to be a multilayer structure. Although the core material 42 in this embodiment has a rectangular cross section, the cross-sectional shape of the core material 42 is not limited to this and may be, for example, a circle, an oval, or a polygon other than a square. Furthermore, the material constituting the core material 42 is not limited to synthetic rubber and, for example, a steel wire or the like may also be used.

[0018] As shown in FIG. 2 , the retainer 5 holds the end (thickened portion 44) of the waterproof sheet 4. The retainer 5 is a metal member having a main body 51 with a through hole formed therein and a locking portion 52 formed at the end of the main body 51. The retainer 5 is hook-shaped (L-shaped) in cross section. The locking portion 52 is a protrusion that protrudes toward the box body 2. The retainer 5 is configured so that the tip of the locking portion 52 abuts against the end 43 of the waterproof sheet 4, and the thickened portion 44 (core material 42) of the waterproof sheet 4 is disposed at the corner between the locking portion 52 and the main body 51. In this manner, the main body 51 presses the waterproof sheet 4 at the position of the thickened portion 44 (core material 42), and the locking portion 52 engages with the thickened portion 44. In other words, the retainer 5 holds the end of the waterproof sheet 4 while being locked to the thickened portion 44 of the waterproof sheet 4. In this embodiment, a spacer 53 is interposed between the main body 51 of the retainer 5 and the skin plate of the box body 2 in a portion away from the tip of the water-stop sheet 4. The spacer 53 has a thickness equivalent to the thickness of the pressed thickened portion 44, and prevents the retainer 5 from tilting when the retainer 5 is fastened with the fixing member (bolt 8), thereby preventing a decrease in the pressing force acting from the locking portion 52 on the thickened portion 44.

[0019] As shown in FIG. 2 , the internal bracket 6 is provided inside the box body 2 at a position corresponding to the clamping member 5. In this embodiment, the internal bracket 6 is primarily formed of an L-shaped steel beam. A through-hole 61 is formed in one of the two orthogonal sections of the internal bracket 6. A nut 62 is fixed to one section of the internal bracket 6, corresponding to the through-hole 61. The clamping member 5 is fixed to the box body 2 by fastening a bolt 8 (fixing member) that passes through the clamping member 5 and the box body 2 to the nut 62 of the internal bracket 6. When the bolt 8 is tightened, the locking portion 52 presses the end 43 (overlapping portion) of the waterstop sheet main body 41, and the main body 51 of the clamping member 5 presses the thickened portion 44 (core material 42). Note that the through-hole 61 in the internal bracket 6 and the through-hole in the box body 2, through which the bolt 8 is inserted, are blocked from the interior space side during construction of a small-section tunnel.

[0020] As shown in Fig. 2, the support member 7 is an arch-shaped metal member or the like, and is attached to the inner surface (the surface on the gap 10 side) of the watertight sheet 4 and is laid across adjacent boxes 2, 2. One end of the support member 7 is connected to the locking portion 52 of the clamp 5 arranged on one box 2 side, and the other end of the support member 7 is connected to the locking portion 52 of the clamp 5 arranged on the other box 2 side. In this embodiment, the ends of the water stop sheet 4 are fixed to the corners (edges) of the opposing surfaces of the adjacent boxes 2, 2. At this time, the water stop sheet 4 is supported by the support member 7 and fixed in an arched state protruding toward the ground G.

[0021] Next, we will explain the large-diameter tunnel construction method using the inter-tunnel watertight structure 3. The steps of the large-diameter tunnel construction method are shown in Figure 4. As shown in Figure 4, the construction of a large-diameter tunnel 1 includes a small-diameter tunnel construction process S1, an inter-box excavation process S2, a caulking process S3, a watertight process S4, and a joining process S5.

[0022] Figure 5 shows the small-section tunnel construction process S1. As shown in Figure 5, in the small-section tunnel construction process S1, multiple adjacent box bodies 2 (small-section tunnels) are formed at intervals. The box bodies 2 are formed by connecting rectangular steel shells 21 axially underground using the shield tunneling method. Because the steel shells formed by combining multiple segments inside the shield machine are placed underground, gaps 10 filled with a filler such as natural ground or backfill material are provided between adjacent box bodies 2. Water-swelling seals (not shown) are attached to the contact surfaces between the steel shells 21. It is preferable to position the water-swelling seals as close to the outer periphery of the main girders as possible. It is desirable to set the width of the gaps 10 large enough to allow workers to enter after the natural ground and backfill material have been removed.

[0023] Figure 6 shows the inter-box excavation step S2. As shown in Figure 4, in the inter-box excavation step S2, the filler (natural ground or backfill material) remaining in the gap 10 between adjacent box bodies 2 is excavated to form a space that workers can enter. In addition, in the inter-box excavation step S2, if necessary, ground improvement GK such as chemical injection is performed on the natural ground G (ground) around the excavation point between the box bodies 2 (above in Figure 4) to prevent the collapse of the natural ground G. In addition, with the space formed by excavating the filler in the gap 10, support may be installed between the box bodies 2 to prevent deformation that would cause the box bodies 2 to approach each other due to earth pressure, etc.

[0024] In the caulking step S3, the joints between the adjacent steel shells 21 are caulked. That is, if a step occurs between the adjacent steel shells 21 due to misalignment caused by the construction of the box body 2, caulking smooths the contact surface between the steel shells 21 and the waterstop sheet 4 at the joints. By eliminating the step in this way, compatibility with the waterstop sheet 4 is improved, and the adhesion (waterstop performance) between the waterstop sheet 4 and the box body 2 can be improved. At this time, the caulking agent is pressed until it reaches the water-swelling seals interposed between the contact surfaces of the steel shells 21.

[0025] Figure 7 shows the water stopping step S4. As shown in Figure 7, in the water stopping step S4, the outside of the gap between adjacent box bodies 2 (the portion facing the ground G) is watertight using the inter-tunnel water stopping structure 3. In the water stopping step S4, a water stop sheet 4 is laid horizontally between the adjacent box bodies 2 and fixed with a clamp 5 (see Figure 2). In this embodiment, an internal bracket 6 is fixed in advance to a predetermined position on the box body 2, and with the clamp 5 in contact with the surface of the water stop sheet 4, a bolt 8 is screwed into the internal bracket 6. The support member 7 is fixed to the clamp 5 in advance. In this way, when the water stop sheet 4 is fixed with the clamp 5, the water stop sheet 4 is arranged in an arch shape along the support member 7.

[0026] In the joining process S5, adjacent box bodies 2 are joined together. In the joining process S5, the portions (remaining portions 22) of adjacent box bodies 2 that are related to the structure of the large cross-section tunnel 1 are joined together, and unnecessary members (removed portions 23) provided on the portions of the box bodies 2 that face the other box bodies 2 are removed (see Figure 1). By repeating the small-section tunnel construction process S1 to the joining process S5, a predetermined number of boxes 2 (small-section tunnels) are constructed and connected, thereby constructing a large-section tunnel 1 of a predetermined shape (see Figure 1).

[0027] As described above, according to the inter-tunnel watertight structure 3 of this embodiment, the watertight sheet 4 is fixed to the pair of box bodies 2 arranged side by side with a simple structure of being pressed down by the pressing tool 5, so that it can be installed easily and reliably. Therefore, it is possible to easily and reliably construct a large-section tunnel 1 made by joining multiple small-section tunnels (box bodies 2).

[0028] Furthermore, the water stop sheet 4 is pressed against the outer surface of the box body 2 and adheres tightly to it, providing excellent watertightness. Furthermore, the water stop sheet 4 is held in place with the thickened portion 44 formed by the core material 42 engaged with the retaining fixture 5, so it is less likely to shift or fall off even when subjected to external pressure such as soil pressure or water pressure. Furthermore, the joints between the adjacent steel shells 21 are caulked to smooth the contact surface with the water stop sheet 4, making it less likely for gaps to form at the contact surface with the water stop sheet 4 and improving watertightness.

[0029] Since the core material 42 is provided at the end of the water stop sheet 4, when the water stop sheet 4 is pressed with the pressing tool 5, the thickened portion 44 (the end of the water stop sheet 4) comes into close contact with the surface of the skin plate, improving water stop performance. This prevents water from leaking into the gap 10 between the box bodies 2.

[0030] The waterproof sheet 4 is held in an arch shape that protrudes toward the ground G by the support members 7, and is therefore less likely to deform due to water pressure, etc. Therefore, even when water pressure, etc., acts, deformation such as denting (bending) toward the gap 10 is suppressed, and damage due to stress concentration, etc. is prevented.

[0031] By arranging internal support members 6 corresponding to the clamping members 5, workability can be improved and the inter-tunnel water-stopping structure 3 can be formed quickly. Since the spacer 53 is interposed between the presser 5 and the skin plate, when the presser 5 is fastened by the bolt 8, it is possible to prevent the presser 5 from tilting relative to the skin plate.

[0032] 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 modified as appropriate within the scope of the invention. For example, in the above embodiment, a case where a small cross-section tunnel (box body 2) is constructed using the shield method is described, but the tunnel construction method used when constructing a small cross-section tunnel is not limited, and may be, for example, a jacking method.

[0033] In the above embodiment, the small-section tunnel construction step S1 to the joining step S5 are repeated to construct a predetermined number of box bodies 2 and join the box bodies 2 together, but the timing for performing the joining step S5 is not limited. For example, the joining step S5 may be performed all at once after the construction of all the box bodies 2 is completed.

[0034] Furthermore, construction of another box body 2 (small cross-section tunnel construction step S1) may be carried out in parallel with the execution of the inter-box body excavation step S2 to the joining step S5 of adjacent box bodies 2. Furthermore, the caulking step S3 may be performed as needed. For example, if there is no difference in level between the joints of the steel shells 21 or if the difference is extremely small, the caulking step S3 may be omitted.

[0035] The number, arrangement and separation distance of the boxes 2 for constructing the large cross-section tunnel 1 are not limited and may be determined as appropriate. The support member 7 may be installed as needed, or may be omitted. The configuration of the support member 7 is not limited, and for example, a lattice-like member processed into an arch shape may be used.

[0036] In the above embodiment, the internal bracket 6 is an L-shaped steel, but the internal bracket 6 may be a steel plate, and the configuration of the internal bracket 6 is not limited. The internal bracket 6 may also be a nut and washer. The nut 62 does not necessarily have to be fixed to the internal bracket 6.

[0037] In the above embodiment, a case where the spacer 53 is interposed between the retainer 5 and the skin plate has been described, but the spacer 53 may be installed as needed. For example, if a step of the same thickness as the thickness of the pressed thickened portion 44 protruding toward the box body 2 is formed in the main body 51 in a portion away from the leading end of the waterstop sheet 4 (if the spacer 53 is integrally formed with the main body 51), there is no need to separately interpose the spacer 53. [Explanation of symbols]

[0038] 1 Large-section tunnel 2 Box (small cross-section tunnel) 21 Steel shell 3. Water-stopping structure between tunnels 4. Waterproof sheet 41 Water-stop sheet body 42 Core material 5 Clamp 6 Internal bracket 7 Support member 8 bolts (fixing members) G. Ground 10 Gap S1 Small section tunnel construction process S2 Excavation process between boxes S3 Caulking process S4 Water stop process S5 Joining process

Claims

1. A waterproof sheet disposed across adjacent box bodies; A tunnel-to-tunnel water stop structure comprising a pressing tool that holds the end of the water stop sheet, A thickened portion is formed at the end of the waterproof sheet, A locking portion is formed at the end of the pressing tool, A water-stop structure between tunnels, characterized in that the clamping device presses the water-stop sheet at the position of the thickened portion and holds the end of the water-stop sheet in a state where it is engaged with the thickened portion by the engaging portion.

2. An internal receiving member is provided inside the housing in a position corresponding to the holding member, The tunnel-to-tunnel water-stop structure described in claim 1, characterized in that the clamp is fixed to the box by fixing a fixing member that penetrates the clamp and the box to the internal support.

3. The inter-tunnel watertight structure according to claim 1, characterized in that the ends of the watertight sheet are fixed to the corners of the opposing surfaces of the adjacent boxes.

4. The inter-tunnel watertight structure according to claim 3, characterized in that an arch-shaped support member is attached to the watertight sheet and is laid across adjacent boxes.

5. The waterproof sheet itself, A water stop sheet comprising: a core material provided at an end of the water stop sheet body; A waterproof sheet characterized in that the ends of the waterproof sheet body are folded back around the core material as an axis, and the overlapping portions formed by folding back are glued or welded.

6. A large-section tunnel construction method using the inter-tunnel watertight structure according to any one of claims 1 to 4, a small-section tunnel construction process for forming a plurality of adjacent boxes at intervals; an inter-case excavation step of excavating spaces between adjacent case bodies; a water stopping process of stopping water between adjacent boxes using the inter-tunnel water stopping structure; and a joining step of joining adjacent boxes together, The box body is formed by connecting a plurality of steel shells in the axial direction using a shield tunneling method or a pipe jacking method, In the water stopping step, the water stopping sheet is installed across the adjacent box bodies, A large-section tunnel construction method characterized in that, in the joining process, adjacent box bodies are joined together and unnecessary parts provided on the parts of the box bodies facing the other box bodies are removed.

7. 7. The large cross-section tunnel construction method according to claim 6, further comprising a caulking step, prior to the water-stopping step, of caulking the joints between adjacent steel shells to smooth the contact surfaces between the joints and the water-stopping sheet.

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