Underwater bottom lining structure

Abstract

To provide a water bottom lining structure which is excellent in water cut-off performance, and hardly causes load transmission to a peripheral structure.SOLUTION: A water bottom lining structure 1 for preventing water from flowing into a working space 2 formed under the water surface includes a slab 4 covering the working space 2, and a cut-off joint 5 provided between an edge of the slab 4 and a peripheral structure. An edge part of the slab 4 is separated from a peripheral structure, and the water cut-off joint 5 has flexible water cut-off members 6 and 6 respectively arranged on the upper surface side and the under surface side of the slab 4.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a waterbed lining structure to be installed on the bottom of a body of water. [Background technology]

[0002] When constructing underground structures by excavating the ground, it is sometimes possible to carry out work with the work space open by laying a cover plate above the work space. When excavating the bottom of a river or other body of water to form an underground structure (tunnel, etc.), a temporary riverbed is formed using a cover structure, allowing the underground structure to be constructed below the riverbed while maintaining the river's flow function. Such a cover structure must have high water-stopping properties.

[0003] Patent Document 1 discloses a lining structure to be installed underwater, which has a plurality of plate members installed on the bottom of the water and sealing members installed in the gaps between the plate members. In the lining structure of Patent Document 1, the sealing members are pressed against the plate members by water pressure, thereby sealing the gaps between the plate members. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-172635 Summary of the Invention [Problem to be solved by the invention]

[0005] When a lining structure is used as a riverbed, it is required to have high water-stopping properties so that work can be done underneath the lining, and it is preferable that the structure be able to follow changes in water level and displacement during earthquakes. In particular, when a lining structure is formed adjacent to surrounding structures, it is preferable that the structure does not transmit loads to surrounding structures when displacement occurs during an earthquake.

[0006] In the lining structure of Patent Document 1, sealing members that are susceptible to water pressure are tightly attached between adjacent structures (plate members, surrounding structures, etc.), so there is a risk that the load will be transferred to other structures when a structure is displaced due to an earthquake, etc. If load transfer occurs between existing surrounding structures, there is a risk that the surrounding structures will be distorted. The present invention aims to propose a submerged lining structure that has excellent watertightness and is less likely to transmit loads to surrounding structures. [Means for solving the problem]

[0007] The present invention provides a submerged lining structure for preventing water from flowing into a working space formed below the water surface, comprising a slab covering the working space and a watertight joint provided between the edge of the slab and a surrounding structure. The edge of the slab is spaced from the surrounding structure. The watertight joint has flexible watertight members arranged on the upper and lower sides of the slab.

[0008] With this underwater lining structure, the slab is spaced apart from surrounding structures, preventing contact with them and reducing load transfer between them even in the event of displacement during an earthquake. Furthermore, watertight joints with flexible watertight members on the upper and lower surfaces of the slab are installed between the edges of the slab and the surrounding structures, preventing water from entering the work space below the slab. Even if one of the flexible watertight members on the upper and lower surfaces of the slab malfunctions, the other maintains watertightness. Furthermore, the flexible watertight members on the lower surface of the slab are visible from within the work space, facilitating inspection and repair.

[0009] Furthermore, if the slab is further equipped with a sensor that detects displacement or deformation of the flexible water-stopping member arranged on the underside of the slab, the flexible water-stopping member arranged on the underside of the slab can be automatically monitored at all times, making it possible to detect and repair leaks early. [Effects of the Invention]

[0010] According to the present invention, it is possible to form a submerged lining structure that prevents water from flowing into a working space formed below the water surface and that is less likely to cause load transmission between the submerged lining and surrounding structures. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view showing an overview of the waterbed lining structure according to this embodiment. [Figure 2] 2A and 2B are diagrams showing an outline of the underwater lining structure, in which (a) is a cross-sectional view taken along line XX in FIG. 1, and (b) is a cross-sectional view taken along line YY in FIG. 1. [Figure 3] FIG. 4 is a cross-sectional view showing a first watertight joint. [Figure 4] FIG. 4 is an exploded view of the first watertight joint of FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view showing a second watertight joint. [Figure 6] FIG. 4 is a cross-sectional view showing a third watertight joint. [Figure 7] FIG. 10 is a cross-sectional view showing a fourth watertight joint. [Figure 8] FIG. 10 is a cross-sectional view showing a fifth watertight joint. [Figure 9] 10 is a flowchart showing the steps of a workspace construction method. [Figure 10] 1A and 1B are cross-sectional views showing the working status of the work space construction method, in which (a) shows the slab installation process and the first air leak test process, and (b) shows the drainage process and the second air leak test process. [Figure 11] 1A and 1B are explanatory diagrams of a waterproof performance confirmation test, in which (a) is a cross-sectional view and (b) is a cross-sectional view of a test device. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this embodiment, a submerged lining structure 1 that prevents water from flowing into a working space 2 formed below the water surface when constructing an underground structure under a riverbed while maintaining the river's flow performance will be described. Figures 1 and 2 show an overview of the submerged lining structure 1. 1 and 2, surrounding structures such as a box culvert B, a pier P, and earth retaining walls W1 and W2 are arranged around the work space 2. In other words, the surrounding structures are the sides of existing structures (box culvert B and pier P in this embodiment) and / or temporary structures (earth retaining walls W1 and W2 in this embodiment) provided along the periphery of the work space 2.

[0013] The waterbed lining structure 1 comprises support piles 3, 3, ... installed on the waterbed, slabs 4, 4, ... covering the work space 2, and watertight joints 5 installed between the edge of one slab 4 and other structures (box culvert B, pier P, retaining walls W1, W2, other slabs 4). As shown in Figure 1, the watertight joints 5 are installed between the edge of each slab 4 and surrounding structures (box culvert B, retaining walls W1, W2), and between the edges of adjacent slabs 4, 4.

[0014] As shown in Figures 2(a) and (b), in this embodiment, the top surface of the work space 2 is covered by connecting multiple slabs 4, 4, ... left and right, front and back. One slab 4 is supported by a support pile 3 while being spaced apart from other structures (surrounding structures and other slabs 4). The slab 4 is laid by placing it on the head of the support pile 3. The weight of the slab 4 acts on the support pile 3, and does not act on other structures (surrounding structures and other slabs 4). The slab 4 in this embodiment is made up of multiple slab segments 41, 41, ... connected together. Water-stopping members (sealing materials, etc.) are provided at the joints between the slab segments 41 to prevent water leakage from the joints between the slab segments 41.

[0015] FIG. 3 shows a waterstop joint 5 (first waterstop joint 51) installed between slabs 4. As shown in FIG. 3, the first waterstop joint 51 includes a pair of upper and lower flexible waterstop members 6, 6. The flexible waterstop members 6 are arranged across the upper and lower surfaces of the slabs 4, 4, which are spaced apart. The flexible waterstop members 6 are made of a resin plate and have a corrugated cross-section. The flexible waterstop members 6 are bendable vertically and are also expandable. The waterstop joint 5 is covered from above with a protective iron plate (protective iron plate 50). The protective iron plate 50 is disposed at a distance from the upper surface of the slab 4 by a bulkhead 501 so as not to come into contact with the flexible waterstop member 6. The protective iron plate 50 prevents damage from river debris (wood chips, etc.) and prevents excessive weight from being placed on the flexible waterstop member 6 due to sediment accumulation.

[0016] The waterstop joint 5 is also provided with a sensor 60 that detects displacement or deformation of the flexible waterstop member 6 located on the underside of the slab 4. The sensor 60 is fixed to the underside of the slab 4 and emits light radially downward toward the lower flexible waterstop member 6. When water accumulates and deforms the lower flexible waterstop member 6, causing it to displace or deform downward, the light emitted from the sensor 60 is reflected by the flexible waterstop member 6. When the sensor 60 receives the reflected light from the lower flexible waterstop member 6, it outputs a signal to an alarm device such as a rotating light installed in the work space. The sensor 60 may also include a light-emitter and a light-receiver installed on both sides of the lower flexible waterstop member 6. When the light emitted from the light-emitter is blocked by the flexible waterstop member 6 and cannot be received by the light-receiver, it detects that the lower flexible waterstop member 6 has been displaced or deformed beyond its allowable value. In addition, the sensor 60 may be a displacement meter that measures the displacement of the lower flexible water-stopping member 6, a strain gauge that measures the strain of the lower flexible water-stopping member 6, a camera that detects deformation of the lower flexible water-stopping member 6, etc.

[0017] FIG. 4 shows an exploded view of the first waterstop joint 51. The first waterstop joint 51 includes an adjusting plate 61 interposed between the edge of the flexible waterstop member 6 and the slab 4, a pressure plate 62 (special square washer) placed on the adjusting plate 61, a first fastening means 63 that applies a pressing force to the pressure plate 62 toward the adjusting plate 61, a second fastening means 64 that applies a pressing force to the flexible waterstop member 6 toward the adjusting plate 61, and gaskets 65 disposed on the upper and lower surfaces of the adjusting plate 61. The adjusting plate 61 has a contact portion 611 that contacts the edge of the flexible waterstop member 6 and an adjusting hole 612 (enlarged hole) that corresponds to the first fastening means 63. The pressure plate 62 is positioned so as to close the adjusting hole 612. The first fastening means 63 has a shaft portion 631 that is fixed to the slab 4 and inserted into the adjusting hole 612. The diameter of the adjustment hole 612 is larger than the diameter of the shaft portion 631 .

[0018] The first fastening means 63 has a shaft portion 631 erected on the upper surface of the slab 4 , a nut 632 screwed onto the shaft portion 631 , and a waterproof washer 633 . The first fastening means 63 is formed by inserting the shaft portion 631 into the adjustment hole 612 of the adjustment plate 61, then disposing the pressure plate 62 and the watertight washer 633 on the adjustment plate 61, and fastening the nut 632 to the shaft portion 631. The first fastening means 63 fixes the adjustment plate 61 to the slab 4. Because the adjustment hole 612 has a hole diameter larger than the outer diameter of the shaft portion 631, the adjustment hole 612 can absorb any error in the size of the gap between the slabs 4. In other words, even if an error occurs in the installation position of the slab 4 and the position of the shaft portion 631 shifts, the position of the adjustment plate 61 can be adjusted, so the separation distance between the joint fixing bolts 641, 641 can be adjusted to match the size of the flexible watertight member 6.

[0019] The packing 65 disposed on the underside of the adjusting plate 61 is strip-shaped and extends in the longitudinal direction of the adjusting plate 61 (perpendicular to the paper surface in FIG. 4 ), and is tightly attached to the underside of the adjusting plate 61 and the upper surface of the slab 4 by the fastening force of the first fastening means 63, preventing water leakage from between the adjusting plate 61 and the slab 4. The packing 65 disposed on the upper side of the adjusting plate 61 is ring-shaped and surrounds the adjusting hole 612 of the adjusting plate 61, and is tightly attached to the upper surface of the adjusting plate 61 and the lower surface of the pressing plate 62 by the fastening force of the first fastening means 63, preventing water between the adjusting plate 61 and the pressing plate 62 from leaking through the adjusting hole 612 to the underside of the adjusting plate 61.

[0020] The second fastening means 64 is composed of a joint fixing bolt 641 fixed to the adjustment plate 61 , a nut 642 screwed onto the joint fixing bolt 641 , and a washer 643 . The second fastening means 64 fastens the flexible water-stopping member 6 to the adjustment plate 61 by fastening a nut 642 to the joint fixing bolt 641 via a washer 643 while the joint fixing bolt 641 is inserted into the flexible water-stopping member 6.

[0021] Figure 5 shows a watertight joint 5 (second watertight joint 52) ​​installed between the edge of the slab 4 and a surrounding structure (box culvert B). As shown in Figure 5, the second watertight joint 52 includes a flexible watertight member 6, a receiving member 7, a filler material 8, and a watertight injection pipe material 9. Note that in this embodiment, a case will be described in which the surrounding structure is an existing concrete box culvert B, but the use, material, structure, shape, etc. of the surrounding structure are not limited.

[0022] The flexible water-stopping member 6 is attached to the receiving member 7 and the slab 4. In this embodiment, the flexible water-stopping member 6 is disposed on both the upper and lower surfaces of the slab 4. In other words, the water-stopping joint 5 uses the flexible water-stopping member 6 to cover the upper and lower surfaces of the gap 10 between the slab 4 and the existing structure.

[0023] The support member 7 is attached to the box culvert B underwater. The support member 7 has a base portion 71 arranged to face the box culvert B, and an attachment flange portion 72 extending from the base portion 71 toward the slab 4. In this embodiment, the base portion 71 is fixed to the existing structure by anchors 73. In this embodiment, three rows of anchors 73 are provided, one above the other, at predetermined intervals along the longitudinal direction of the support member 7.

[0024] The flexible water-stopping member 6 is fixed to the mounting flange portion 72 via bolts. A primer is applied or sprayed onto the back surface of the receiving member 7 (the surface facing the surrounding structure) in advance to improve adhesion with the filler 8. In addition, a water-stopping rubber (not shown) with a thickness (for example, 20 mm) is installed at the joints between the receiving members 7 in the depth direction of the page, making it possible to absorb accumulated errors, etc.

[0025] The base plate portion 71 is fixed to the existing structure so that its upper end is positioned at the same height as the upper surface of the slab 4. The mounting flange portion 72 is provided in two locations: at the upper end of the base plate portion 71 and at a position at the same height as the lower surface of the slab 4. The receiving member 7 is fixed to the box culvert B1 so that its upper end surface is at the same height as the upper surface of the slab 4 by adjusting the length of its protrusion from the upper surface of the box culvert B1 in accordance with the height position of the slab 4.

[0026] The filler 8 is filled between the surrounding structure (box culvert B) and the base plate 71. In this embodiment, the filler 8 is made of underwater non-separating concrete or underwater non-separating mortar. In this embodiment, a sealant 74 is interposed between the lower end of the base plate 71 and the box culvert B to prevent the filler 8 from leaking out. The material that makes up the sealant 74 is not limited, but in this embodiment, it is made of rubber sponge.

[0027] The water-stopping injection pipe material 9 is embedded in the interfacial filling material 8. In this embodiment, two water-stopping injection pipe materials 9 are embedded, one of which abuts against the base plate 71, and the other of which abuts against the existing structure. The water-stopping injection pipe material 9 is made of a pipe material that is permeable to liquid, and when a water-stopping agent is pumped through the water-stopping injection pipe material 9, some of the agent seeps out, causing the water to stop. If a leak occurs between the interfacial filling material 8 and the box culvert B or the base plate 71, the water-stopping agent is pumped through the water-stopping injection pipe material 9, causing the water to stop.

[0028] Figure 6 shows the third waterproof joint 53. As shown in Figure 6, the third waterproof joint 53 is a waterproof joint 5 provided between the edge of the slab 4 and a surrounding structure (pier P) provided at a position higher than the top surface of the slab 4. The third waterproof joint 53 includes a flexible waterproof member 6, a receiving member 7, a filling material 8, and a waterproof injection pipe material 9.

[0029] The receiving member 7 is attached to a pier P (existing structure) underwater. The receiving member 7 has a base plate portion 71 arranged to face the pier P, and an attachment flange portion 72 that projects from the base plate portion 71 toward the slab 4. In this embodiment, the base plate portion 71 is fixed to the pier P with anchors 73. The flexible water-stopping member 6 is fixed to the attachment flange portion 72. In this embodiment, the base plate portion 71 is fixed to the pier P so that the lower end of the base plate portion 71 is positioned at the same height as the underside of the slab 4. The attachment flange portions 72 are provided at the middle and lower end of the base plate portion 71 to correspond to the height positions on the upper and lower surfaces of the slab 4.

[0030] In addition, the details of the flexible water-stopping member 6, the filler material 8 and the water-stopping injection pipe material 9 are similar to those of the flexible water-stopping member 6, the filler material 8 and the water-stopping injection pipe material 9 of the second water-stopping joint 52, so detailed explanations will be omitted.

[0031] Figure 7 shows the waterproof joint 5 (fourth waterproof joint 54) installed between the slab 4 and the earth-retaining wall W1. As shown in Figure 7, the fourth waterproof joint 54 is used when the upper surface of the slab 4 is arranged at a position higher than the upper end of the earth-retaining wall W1.

[0032] The fourth watertight joint 54 comprises a receiving member 7a attached to the upper end of the retaining wall W1, a flexible watertight member 6 attached to the receiving member 7a and the slab 4, a filler material 8, and a watertight injection pipe material 9. The receiving member 7a has a cap member 75 that is placed over the upper end of the retaining wall W1, and an adjustment member 76 that is erected on the upper end surface and side surface of the retaining wall W1. The cap member 75 has a pair of engaging portions 751, 751 facing each other across the retaining wall W1, and a top plate portion 752 disposed above the retaining wall W1, and has a portal-like cross section. Note that the cap member 75 of this embodiment has a portal-like structure in which the pair of engaging portions 751, 751 and the top plate portion 752 are integrated, but the cap member 75 may be manufactured in sections and assembled into a portal shape on-site by bolting or the like.

[0033] The adjustment member 76 includes a height adjustment member 761 for adjusting the installation height of the cap member 75 relative to the earth-retaining wall W1 and a lateral adjustment member 762 for adjusting the lateral position (front-to-back position) of the cap member 75 relative to the earth-retaining wall W1. The adjustment member 76 is made of a bolt. The top plate portion 752 has a bolt hole through which the height adjustment member 761 can be inserted. The height adjustment member 761 is threaded into the bolt hole. The lower end of the height adjustment member 761 abuts against the upper end surface of the earth-retaining wall W1, and rotating the height adjustment member 761 moves the top plate portion 752 (cap member 75) up and down. The engagement portion 751 also has a bolt hole through which the lateral adjustment member 762 can be inserted. The lateral adjustment member 762 is threaded into the bolt hole. Rotating the lateral adjustment member 762 moves the cap member 75 forward and backward relative to the earth-retaining wall W1. That is, the cap member 75 can be adjusted in position up and down, front and back, and its inclination can be corrected relative to the earth retaining wall W1 using the height adjustment member 761 and the lateral adjustment member 762.

[0034] The flexible water-stopping members 6 are fixed to the upper surface (upper surface of the top plate portion 752) and lower surface (lower end of the engagement portion 751) of the cap member 75. One end of the upper flexible water-stopping member 6 is fixed to the upper surface of the cap member 75, and the other end is fixed to the upper surface of the slab 4. Furthermore, one end of the lower flexible water-stopping member 6 is fixed to the lower end of the cap member 75 (engagement portion 751), and the other end is fixed to the lower surface of the slab 4. In cases where the height of the cap member 75 is high and the height of the engagement portion 751 does not match that of the lower surface of the slab 4, the flexible water-stopping members 6 may be attached to the side of the cap member 75.

[0035] The filler material 8 is filled inside the cap member 75 (the space surrounded by the top plate portion 752, the engaging portion 751, and the upper end of the retaining wall W1). The filler material 8 is made of underwater non-separating concrete or underwater non-separating mortar. In addition, a sealing material 74 is interposed between the retaining wall W1 and the cap member 75 (the lower end of the engaging portion 751), preventing the filler material 8 from leaking out.

[0036] The waterproof injection pipe material 9 is embedded in the fill material 8. In this embodiment, two waterproof injection pipe materials 9, 9 are embedded, one of the waterproof injection pipe material 9 abutting the inner surface of the engagement portion 751, and the other of the waterproof injection pipe material 9 abutting the retaining wall W1.

[0037] Figure 8 shows the watertight joint 5 (fifth watertight joint 55) provided between the slab 4 and the side surface of the earth-retaining wall W2. As shown in Figure 8, the fifth watertight joint 55 is used when the slab 4 is disposed at a position lower than the upper end of the earth-retaining wall W2. The fourth waterproof joint 54 includes a flexible waterproof member 6, a receiving member 7b, a filler material 8, and a waterproof injection pipe material 9.

[0038] The flexible water-stopping members 6 are attached to the receiving member 7b and the slab 4. In this embodiment, the flexible water-stopping members 6 are arranged on both the upper and lower surfaces of the slab 4. In other words, the water-stopping joint 5 uses the flexible water-stopping members 6 to cover the upper and lower surfaces of the gap 10 between the slab 4 and the earth-retaining wall W2 (existing structure).

[0039] The receiving member 7b is attached to the earth-retaining wall W2 (surrounding structure) underwater. The receiving member 7b has a base plate portion 71 arranged to face the side of the earth-retaining wall W2, a mounting flange portion 72 extending from the base plate portion 71 toward the slab 4, and a bottom formwork 77 extending laterally from the side of the earth-retaining wall W2. The base plate portion 71 is erected on the bottom formwork 77 and fixed to the earth-retaining wall W2 via stud bolts 78 protruding from the side of the earth-retaining wall W2. The base plate portion 71 is attached to the earth-retaining wall W2 and forms a flat surface. The flexible water-stopping member 6 is fixed to the mounting flange portion 72. The earth-retaining wall W2 is formed by connecting steel pipe sheet piles, and the side of the earth-retaining wall W2 has an uneven shape consisting of multiple connected semi-cylindrical surfaces.

[0040] The filler 8 is filled between the surrounding structure (earth-retaining wall W2) and the receiving member 7b. That is, the filler 8 is filled in the space surrounded by the earth-retaining wall W2, the base plate 71, and the bottom formwork 77. The filler 8 is made of underwater non-segregating concrete or underwater non-segregating mortar.

[0041] The waterproof injection pipe material 9 is embedded in the fill material 8. In this embodiment, two waterproof injection pipe materials 9 are embedded, one of which abuts against the base plate portion 71, and the other of which abuts against the existing structure.

[0042] Next, we will explain the method for constructing a work space using the underwater lining structure 1. Figure 9 shows the steps of the work space construction method. As shown in Figure 9, the work space construction method includes a slab installation process S1, a first air leak test process S2, a drainage process S3, and a second air leak test process S4. Figure 10 shows the working status of the work space construction method.

[0043] In the slab installation process S1, as shown in Figure 10(a), after the support piles 3 are driven, a slab 4 made of precast members is sunk above the water bottom GL, and a flexible waterstop member 6 is installed between the upper edge of the slab 4 and the surrounding structure to form a waterstop joint 5. In the slab installation process S1, a flexible waterstop member 6 is also installed between the upper edge of adjacent slabs 4, 4 to form a waterstop joint 5. The flexible waterstop member 6 is welded on the water to a predetermined length, and after ensuring continuity, it is sunk and installed between the slab 4 and the surrounding structure, etc.

[0044] The support member 7 is fixed to the existing structure before the slab 4 is sunk. An example of a method for installing the support member 7 is shown below. First, a rebar detector is used to check the reinforcement status of the existing structure and consider the placement of anchors 73. Next, holes are drilled underwater in the existing structure to form anchor holes. Subsequently, anchors 73 are installed in the anchor holes. Bolt holes are formed in the support member 7 corresponding to the placement of the anchors 73 installed in the existing structure. Then, the anchors 73 are inserted into the bolt holes to fix the support member to the existing structure.

[0045] In the first air leak test process S2, gas is pumped under the flexible water stop member 6 to check that there is no air leakage between the receiving member and the flexible water stop member 6 and between the slab 4 and the flexible water stop member 6. If air leakage is confirmed, the bolts of the flexible water stop member 6 are tightened, the member is replaced, or water is injected from the water stop injection pipe material 9. In the draining step S3, as shown in FIG. 10(b), water is drained from the space (work space 2) between the bottom of the water and the slab 4 through a drain outlet (not shown) formed at a predetermined position.

[0046] In the second air leak test process S4, gas is pumped into the space to confirm that there is no air leakage from areas other than the watertight joints 5, such as between the slab segments 41 or between the surrounding structures and the receiving members. Once watertightness has been confirmed in the second air leak test process S4, a flexible watertight member 6 is installed from within the work space 2 between the underside edge of the slab 4 and the surrounding structure.

[0047] According to the underwater lining structure of this embodiment, each slab 4 is installed away from other structures (surrounding structures, other slabs 4), so even if displacement occurs during an earthquake, the slab 4 is unlikely to come into contact with the surrounding structures, and load transfer between them is unlikely to occur. In addition, watertight joints 5 are installed between the edges of the slabs 4 and the surrounding structures, etc., so that water inflow into the work space 2 below the slabs 4 is also suppressed.

[0048] The watertight joint 5 has flexible watertight members 6 arranged on the upper and lower sides of the slab 4, so that even if a malfunction occurs in one of the flexible watertight members 6, watertightness is maintained by the other flexible watertight material.

[0049] Furthermore, in the watertight joint 5, the adjustment hole 612 formed in the adjustment plate 61 has a hole diameter larger than the diameter of the shaft portion 631 of the first fastening means 63, so even if an error occurs in the size of the gap between the slab 4 and the surrounding structure, the error can be absorbed by the adjustment hole 612 and the flexible watertight member 6 can be installed. Therefore, the watertightness provided by the flexible watertight member 6 is maintained. In the joint structure between the slab 4 and the flexible water-stopping member 6, the use of the water-stopping washer 633 and the packing 65 prevents water leakage from the adjustment hole 612, ensuring water-stopping performance.

[0050] When a watertight joint 5 is installed between a slab 4 and a surrounding structure, the flexible watertight member 6 is not attached directly to the surrounding structure but is attached via a receiving member 7, so even if there are unevenness or steps in the surrounding structure, the flexible watertight member 6 can be installed with precision, thereby ensuring high watertightness.

[0051] Filling material 8 is filled between the receiving member 7 and the surrounding structure, so that water can be prevented from leaking from the gap between the receiving member and the surrounding structure. In addition, since the filling material 8 is provided with a water-stopping injection pipe material 9 embedded therein, even if a water leak occurs between the surrounding structure and the receiving member 7 for some reason, water-stopping can be ensured by injecting a water-stopping agent through the water-stopping injection pipe material 9.

[0052] Since the receiving member 7 of the fourth watertight joint 54 has an adjustment member 76, the height position of the cap member 75 can be adjusted to a height position corresponding to the slab 4, even if there is a step at the upper end of the retaining wall W1.

[0053] A sensor 60 is provided to detect the displacement of the flexible water-stopping member 6 provided on the underside of the slab 4, so that leakage caused by damage to the flexible water-stopping member 6 provided on the upper side of the slab 4 can be detected by the deformation of the flexible water-stopping member 6 on the underside, and repairs can be made promptly. The sensor 60 is managed by a monitoring system, and an alarm signal is sent when a leakage is detected.

[0054] The flexible water-stopping member 6 provided on the underside of the slab 4 is installed in a dry environment after the work space 2 is formed, thereby improving the reliability of water-stopping. The lower flexible water-stopping member 6 can be inspected visually, and repair and replacement work can be carried out in a dry environment, making the work easy.

[0055] According to the work space construction method of this embodiment, the work space 2 is formed while checking watertightness through the first air leak test process and the second air leak test process, so it is possible to more reliably prevent water from leaking after work begins using the work space 2. Therefore, work interruptions or repairs due to water leaks are less likely to occur, and efficient construction work can be carried out below water level.

[0056] Here, a water-stopping performance confirmation test carried out to confirm the water-stopping performance of the fixing structure of the receiving member 7 (base plate portion 71) using the anchor 73 will be described. In the watertight performance confirmation test, as shown in Fig. 11(a), the watertightness of the fill material 8 is confirmed when a tensile force generated by the action of superimposed water pressure Wp on the flexible watertight member 6 or a horizontal force L during an earthquake is applied to the second watertight joint 52. An outline of the test is shown in Fig. 11(b).

[0057] As shown in Figure 11(b), in the water-stopping performance confirmation test, two rows of anchors 73, 73 were fixed to the surface of a concrete member C formed on a support frame K, and a base member 71 was installed using the anchors 73, 73. Filling material 8 was then filled between the base member 71 and the concrete member C. With water W stored on the filler material 8, a tensile force F was applied diagonally downward using a tensile force loading jack J installed on the support frame K to the top end of the base member 71, which is equivalent to normal conditions, high tides, and earthquakes, to check for water leakage. Table 1 shows the test results. As shown in Table 1, no water leakage occurred under normal conditions, high tides, or earthquakes. Therefore, it was confirmed that by fixing the base portion 71 below the mounting portion (mounting flange portion 72) of the flexible water-stopping member 6 using two upper and lower anchors 73, 73, leakage from the filling material 8 can be suppressed even when a tensile force F acts on the base portion 71 due to water pressure Wp or horizontal force L acting on the flexible water-stopping member 6.

[0058] [Table 1]

[0059] 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 present invention. In the above embodiment, the case where a plate-shaped slab 4 is laid is described, but an open channel may also be formed by laying a slab 4 with walls erected on its sides. In addition, the number of slab segments that make up the slab 4 is not limited and may be determined appropriately.

[0060] The shape of the flexible water-stopping member 6 is not limited, and the planar shape, width, length, etc. may be set appropriately depending on the installation location. For example, flexible water-stopping members 6 installed at corners may be L-shaped in plan view, and flexible water-stopping members 6 installed at intersections may be T-shaped or cross-shaped in plan view. Furthermore, the width of the flexible water-stopping member 6 and the number of irregularities (waves) may be determined appropriately depending on the width of the installation location (the gap between the slab and surrounding structures) and the magnitude of the expected displacement during an earthquake. [Explanation of symbols]

[0061] 1 Underwater lining structure 2. Workspace 3 Support pile 4. Slab 41 Slab division body 5 Water stop fitting 6 Flexible water-stopping material

Claims

1. A water bottom lining structure that prevents water from flowing into a working space formed under the water surface, a slab covering the workspace; and a waterproof joint provided between the edge of the slab and a surrounding structure, The edge is spaced apart from the surrounding structure; A water bottom lining structure characterized in that the water stop joint has flexible water stop members arranged on the upper and lower sides of the slab.

2. The underwater lining structure according to claim 1, further comprising a sensor for detecting displacement or deformation of the flexible water-stopping member arranged on the underside of the slab.

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