Lid for underground structure and method for constructing lid for underground structure

Abstract

To provide a lid for underground structure which suppresses a liquid body such as rainwater and oil flowing in from a road surface entering the underground structure side through a flow passage formed in a gap between a frame body and a lid body.SOLUTION: A lid 1A for underground structure includes: a flow passage 7 which is the flow passage 7 formed in a gap between a frame body 4 and a lid body 5, and in which a liquid body W flowing in from a road surface RS flows; and a seal material 8 arranged in the flow passage 7. The flow passage 7 includes: a first flow passage 90 having a first flow passage width T1; a second flow passage 100 positioned on the downstream side of the first flow passage 90, and having a second flow passage width T2 which is larger than the first flow passage width T1; and a connection flow passage 110 for connecting the first flow passage 90 and the second flow passage 100. The connection flow passage 110 includes a pair of widened surfaces 111, 112 which widen the flow passage width by being widened with each other toward a third flow passage width T3 larger than the first flow passage width T1. The seal material 8 includes a first seal part 120 arranged so as to come into contact with both of the pair of widened surfaces 111, 112.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a cover for an underground structure and a method for installing a cover for an underground structure. [Background technology]

[0002] Patent Document 1 discloses a watertight manhole structure in which an inner lid is supported by a receiving frame fixed watertightly to the inner wall of the manhole, an elastic sealing member is interposed between the receiving frame and the inner lid, and the sealing member is pressed to seal the space between the receiving frame and the inner lid, in order to provide a low-cost, easy-to-operate structure that can reliably seal a manhole from water.The watertight manhole structure discloses that the inner lid is provided with a pressing member that moves back and forth radially of the cover plate that makes up the main part of the inner lid, and that moves in the thickness direction of the cover plate as an operating tool is operated, and the receiving frame has a holding portion that protrudes inward from the peripheral wall portion opposite the lid receiving portion on which the inner lid is placed, and when the pressing member is advanced radially outward and pressed against the holding portion by operating the operating tool, the lid plate is pressed in the opposite direction, and the sealing member is sandwiched and pressed between the lid receiving portion side and the lid plate side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-218722 A (Abstract) Summary of the Invention [Problem to be solved by the invention]

[0004] In covers for underground structures, it is important to prevent liquids such as rainwater and oil flowing in from the road surface from seeping into the underground structure through the flow path formed in the gap between the frame and the cover. [Means for solving the problem]

[0005] One aspect of the present invention is a lid for an underground structure, comprising: a frame body forming an opening connecting a road surface and an underground structure; a lid body supported by the frame body so as to be openable and closable; a flow path formed in the gap between the frame body and the lid body when the lid body is closed on the frame body, through which a liquid material flowing from the road surface flows; and a sealing material disposed in the flow path. The flow path includes a first flow path having a first flow path width, a second flow path located downstream of the first flow path and having a second flow path width larger than the first flow path width, and a connecting flow path connecting the first flow path and the second flow path. The connecting flow path includes a pair of widening surfaces that widen each other to a third flow path width larger than the first flow path width, thereby widening the flow path width. The sealing material includes a first seal portion disposed so as to contact both of the pair of widening surfaces.

[0006] In this underground structure cover, the connecting flow path connecting the upstream first flow path and the downstream second flow path includes a pair of widening surfaces that widen toward a flow path width greater than the first flow path width, i.e., that widen from both sides relative to the first flow path. Therefore, by contacting a sealant with both of the pair of widening surfaces, the sealant can be positioned so that it overflows on both sides of the first flow path beyond the first flow path width. This improves the flow path blocking effect, thereby preventing liquid flowing in from the road surface from seeping into the underground structure.

[0007] The lid body includes a lid main body portion capable of closing the opening and a load transmission portion that transmits the load of the lid main body portion to the frame body, and the frame body includes a load support portion that supports the load of the lid body transmitted by the load transmission portion, and the load transmission portion includes a first flat surface extending in a second direction perpendicular to a first direction parallel to the central axis of the opening, and the load support portion includes a second flat surface arranged across a first flow path width from the first flat surface, and it is preferable that the first flat surface includes a first connecting portion that connects to one of the pair of widening surfaces, and the second flat surface includes a second connecting portion that connects to the other of the pair of widening surfaces.

[0008] In this underground structure cover, the load transmission portion includes a first flat surface, and the load support portion includes a second flat surface disposed across the first flow path width from the first flat surface. This allows the two flat surfaces to be positioned opposite each other in the load transmission path, making it easy to reduce the width of the first flow path. This allows the sealing material to contact a pair of widened surfaces immediately downstream of the reduced first flow path. This makes it easy to reduce the size of the sealing material, and using a compact sealing material makes it easy to efficiently improve the flow path blocking effect.

[0009] The lid body preferably includes a protrusion protruding from a first position of the lid main body portion in a first direction from the road surface side toward the underground structure side in the first direction, and a connecting portion connecting the first flat surface and the protrusion, the connecting portion including a recess recessed toward the opposite side of the first direction relative to the first flat surface, the recess including a bottom surface formed at the first position and a wall surface rising from the bottom surface to face the protrusion, the wall surface including one widening surface, and the sealing material preferably including a second sealing portion arranged to contact the protrusion.

[0010] In this underground structure lid, by inserting a sealant into the recess of the connection connecting the first flat surface and the protruding portion, the sealant can be brought into contact with the protruding portion as well as the pair of widening surfaces. Therefore, even if a liquid leaks from the contact area between one of the pair of widening surfaces on the recess wall and the first seal, the contact area between the protruding portion facing the recess wall and the second seal can prevent further penetration of the liquid. Therefore, it is possible to provide an underground structure lid that further improves the flow path blocking effect.

[0011] Another aspect of the present invention is a method for installing a cover for an underground structure. The cover for an underground structure includes a frame body forming an opening connecting the road surface and the underground structure, a cover body supported by the frame body so as to be openable and closable, and a flow path formed in the gap between the frame body and the cover body, through which a liquid material flows from the road surface. The flow path includes a first flow path having a first flow path width, a second flow path located downstream of the first flow path and having a second flow path width larger than the first flow path width, and a connecting flow path connecting the first flow path and the second flow path. The connecting flow path includes a pair of widening surfaces that widen each other to a third flow path width larger than the first flow path width, thereby widening the flow path width. The method includes attaching a sealant to one of the pair of widening surfaces so as to contact the first widening surface before the cover is closed on the frame body, and then closing the cover on the frame body after the attachment, thereby bringing the sealant into contact with the other of the pair of widening surfaces. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of a cover for an underground structure according to one embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the underground structure cover shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view of the main part of the underground structure cover in a state where the cover body is closed on the frame body. [Figure 4] FIG. 4 is a schematic diagram for explaining the configuration of a flow path formed in the gap between the frame and the lid. [Figure 5] FIG. 5 is a cross-sectional view for explaining a method for constructing a cover for an underground structure. [Figure 6] FIG. 6 is a cross-sectional view of a main part of a cover for an underground structure according to a modified example. [Figure 7] FIG. 7 is a schematic diagram for explaining the configuration of the flow path provided in the underground structure cover shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Fig. 1 is a cross-sectional view of an underground structure lid 1A according to one embodiment of the present invention. Fig. 2 is an exploded perspective view of the underground structure lid 1A. The underground structure lid 1A comprises a frame body 4 that forms an opening 3 connecting a road surface RS and an underground structure 2, a lid body 5 that is supported by the frame body 4 so as to be able to open and close, a guide mechanism 6 that guides the movement of the lid body 5 so that the lid body 5 moves along a predetermined movement trajectory when opening and closing the lid body 5 relative to the frame body 4, a flow path 7 that is formed in the gap between the frame body 4 and the lid body 5 when the lid body 5 is closed relative to the frame body 4 in a closed state (hereinafter simply referred to as the "closed state"), and a sealing material 8 that is disposed in the flow path 7. Examples of underground structure covers 1A include manhole covers, large iron covers, and sewage manhole covers that close openings connecting underground buried objects or underground structure facilities in sewers to the ground, openable iron covers for common trenches that protect underground facility equipment or underground cables in electrical or communication equipment, iron covers for power transmission and distribution, fire hydrant covers that function as opening and closing doors connecting buried conduits under the road surface in water supply or gas piping and their associated equipment to the ground, water control valve covers, gate valve covers, air valve covers, gas piping covers, water meter covers, etc.

[0014] The frame 4 has an inner peripheral surface 4a that defines the opening 3 and has a substantially cylindrical shape. The opening 3 is formed by the inner peripheral surface 4a of the frame 4, and therefore has a substantially circular shape. In this example, the central axis C1 of the opening 3 extends along the vertical direction VD. The central axis C1 of the opening 3 is a direction that intersects with the road surface RS, typically a direction perpendicular to the road surface RS. The lid 5 includes a lid main body 10 that can close the opening 3, a load transfer part 20 that transfers the load of the lid main body 10 to the frame 4, multiple protrusions 30 that protrude from the lid main body 10, and a reinforcing part 40 that reinforces the lid main body 10. The lid main body 10 is substantially disc-shaped and has an upper surface 11 that is exposed to the road surface RS in the closed state, a lower surface 12 that faces the opening 3 in the closed state, and an outer peripheral surface 13 that connects the upper surface 11 and the lower surface 12. In this example, the central axis C2 of the lid main body 10 coincides with the central axis C1 of the opening 3 in the closed state. The load transfer portion 20 and the multiple protrusions 30 are formed integrally with the lid main body 10. The load transfer portion 20 is provided on the outer periphery of the underside 12 of the lid main body 10, and in this example, is provided continuously over the entire area (entire circumference) of the lid main body 10 in the circumferential direction CD. Each protrusion 30 is supported in a cantilevered manner by the lid main body 10. The multiple protrusions 30 are lined up along the circumferential direction CD of the lid main body 10. The reinforcing portion 40 includes a lattice-shaped rib provided on the underside 12 of the lid main body 10.

[0015] The guide mechanism 6 includes a guide member 45 provided on the frame 4, and a guided member 46 provided on the cover 5 and guided relative to the guide member 45. The guide member 45 has a guide hole 45a that guides the guided member 46. The guided member 46 includes a rod-shaped moving part 47 that is fixed to the cover 5 and moves relative to the guide member 45 while inserted in the guide hole 45a, and a retaining part 48 that prevents the moving part 47 from coming out of the guide hole 45a.

[0016] FIG. 3 is a cross-sectional view of a key portion of the underground structure lid 1A in a closed state. Unless otherwise specified, each component will be described assuming the closed state. Each protrusion 30 protrudes from a first position P1 provided on the lid main body 10 in a first direction D1 (typically a vertical direction VD) parallel to the central axis C1 of the opening 3, from the road surface RS toward the underground structure 2 (typically downward). Each protrusion 30 includes an inner surface 31 located inside in a radial direction RD centered on the central axis C1, an outer surface 32 located outside in the radial direction RD, and a tip surface 33 connecting the inner surface 31 and the outer surface 32. Each protrusion 30 includes a base portion 34 connected to the lid main body 10 at the first position P1, a deformable portion 35 connected to the base portion 34, and a tip portion 36 connected to the deformable portion 35. The deformable portion 35 is elastically deformed by contacting the frame 4 to attenuate vibration of the lid body 5 relative to the lid main body 10.

[0017] The load transfer portion 20 includes a first flat surface 21 extending in a second direction D2 (typically, a horizontal direction) perpendicular to the first direction D1. The first flat surface 21 has, for example, an annular shape centered on the central axis C2 of the lid main body 10. The lid 5 further includes a connecting portion 50 connecting the load transfer portion 20 and the plurality of protrusions 30. The connecting portion 50 includes a recess 51 recessed relative to the first flat surface 21 toward a second direction D12 (typically, upward) opposite to the first direction D11. The recess 51 has an annular shape centered on the central axis C2 of the lid main body 10. The recess 51 includes a bottom surface 52 formed at a first position P1 and a pair of wall surfaces (a first wall surface 53 and a second wall surface 54) rising from the bottom surface 52 toward the first direction D11. The first wall surface 53 is continuous with the first flat surface 21 and faces the protrusion 30. The second wall surface 54 is continuous with the outer surface 32 of the protrusion 30.

[0018] The frame 4 includes a deformation-inducible portion 60 capable of inducing elastic deformation in the deformable portion 35 of the protrusion 30, a load-supporting portion 70 that supports the load transmitted from the load-transmitting portion 20, and a main body accommodating portion 80 that accommodates the lid main body 10. The deformation-inducible portion 60 includes a non-contact surface 61 that does not contact the protrusion 30 and a contact surface 62 that is connected to the non-contact surface 61 on the side of the non-contact surface 61 in the first direction D11 and that contacts the deformable portion 35. The load-supporting portion 70 includes a second flat surface 71 that extends in a second direction D2 perpendicular to the first direction D1. The second flat surface 71 has an annular shape centered on the central axis C1 of the opening 3. The second flat surface 71 is connected to the non-contact surface 61 of the deformation-inducible portion 60. The main body accommodating portion 80 includes an opposing surface 81 that faces the outer circumferential surface 13 of the lid main body 10. The opposing surface 81 is continuous with the second flat surface 71. The contact surface 62, the non-contact surface 61, the second flat surface 71 and the opposing surface 81 form part of the inner circumferential surface 4a of the frame 4.

[0019] FIG. 4 is a schematic diagram illustrating the configuration of the flow path 7. The liquid material W flowing in from the road surface RS (see FIG. 1) flows through the flow path 7. The flow path 7 includes a first flow path 90 having a first flow path width T1, a second flow path 100 located downstream of the first flow path 90 and having a second flow path width T2 larger than the first flow path width T1, and a connecting flow path 110 connecting the first flow path 90 and the second flow path 100. The connecting flow path 110 includes a pair of widening surfaces 111, 112 (the first widening surface 111 and the second widening surface 112) that widen toward each other toward a third flow path width T3 larger than the first flow path width T1, thereby widening the flow path width. The first widening surface 111 is continuous with the bottom surface 52 of the recess 51 of the lid 5, and the second widening surface 112 is continuous with the non-contact surface 61 of the frame 4. In this example, the first widening surface 111 is formed by the first wall surface 53. The first flat surface 21 includes a first connecting portion 91 that is continuous with the first widening surface 111, and the second flat surface 71 includes a second connecting portion 92 that is continuous with the second widening surface 112.

[0020] The first flow path 90 is formed in the gap between the first flat surface 21 and the second flat surface 71, and the first flow path width T1 is the distance between the first flat surface 21 and the second flat surface 71. The liquid material W flows into the first flow path 90 through the gap between the opposing surface 81 and the outer peripheral surface 13 of the lid main body 10. The connection flow path 110 includes a gap 110a between a pair of widening surfaces 111, 112. In this example, the connection flow path 110 includes a recess 51 having a first wall surface 53 that functions as the first widening surface 111, and a gap 110b between the second widening surface 112 and the outer surface 32 facing the widening surface 112. An example of the third flow path width T3 of the connection flow path 180 is the distance between the intersection of the bottom surface 52 of the recess 51 and the first widening surface 111 and the intersection of the non-contact surface 61 of the frame 4 and the second widening surface 112. The second flow path 100 is a flow path that connects to the downstream side of the connecting flow path 110, and the second flow path width T2 is the distance between the non-contact surface 61 of the frame 4 and the outer surface 32 of the protruding portion 30. The sealing material 8 is, for example, an elastic member such as an O-ring. The sealing material 8 includes a first seal portion 120 that is arranged to contact both of the pair of widening surfaces 111, 112, a second seal portion 121 that is arranged to contact the outer surface 32 of the protruding portion 30 (strictly speaking, the second wall surface 54), and a third seal portion 122 that is arranged to contact the bottom surface 52 of the recess 51.

[0021] According to this underground structure lid 1A, the connecting flow path 110 connecting the upstream first flow path 90 and the downstream second flow path 100 includes a pair of widening surfaces 111, 112 that widen toward a flow path width (third flow path width T3) larger than the first flow path width T1, i.e., that widen in both directions relative to the first flow path 90. Therefore, by bringing the sealing material 8 into contact with both of the pair of widening surfaces 111, 112, the sealing material 8 can be arranged so that it overflows on both sides of the first flow path 90 beyond the first flow path width T1. This improves the blocking effect of the flow path 7, and as a result, it is possible to prevent the liquid material W flowing in from the road surface RS from seeping into the underground structure 2.

[0022] Furthermore, in this underground structure cover 1A, the load transmission portion 20 includes a first flat surface 21, and the load support portion 70 includes a second flat surface 71 disposed across the first flow path width T1 from the first flat surface 21. This allows the two flat surfaces 21, 71 to be disposed opposite each other in the load transmission path along which repeated loads caused by the movement of a vehicle or the like are transmitted, making it easy to reduce the first flow path width T1. This allows the sealing material 8 to come into contact with a pair of widened surfaces 111, 112 immediately downstream of the reduced first flow path 90. This allows the sealing material 8 to be made smaller, and the use of a compact sealing material 8 can efficiently improve the blocking effect of the flow path 7.

[0023] Furthermore, in this underground structure lid 1A, by inserting a sealant 8 into the recess 51 of the connecting portion 50 connecting the first flat surface 21 and the protruding portion 30, the sealant 8 can be brought into contact with the pair of widening surfaces 111, 112 as well as the bottom surface 52 of the recess 51 and the protruding portion 30. Therefore, even if the liquid material W leaks from the contact portion 120a between the first widening surface 111 and the first seal portion 120 on the first wall surface 53 of the recess 51, the contact portion 122a between the bottom surface 52 of the recess 51 and the third seal portion 122 and the contact portion 121a between the protruding portion 30 facing the first widening surface 111 and the second seal portion 121 can suppress further penetration of the liquid material W. Therefore, it is possible to provide an underground structure lid 1A that further improves the blocking effect of the flow path 7.

[0024] FIG. 5 is a cross-sectional view illustrating a method for constructing the underground structure lid 1A. Here, the method for constructing the underground structure lid 1A will be described using FIGS. 1, 3, and 5. When constructing the underground structure lid 1A, first, in the open state where the lid body 5 is open relative to the frame body 4 as shown in FIG. 5, i.e., before the lid body 5 is closed relative to the frame body 4, the sealing material 8 is fitted into the recess 51 and attached to the lid body 5. At this time, as shown in the enlarged view of FIG. 5, the sealing material 8 is attached to the lid body 5 so as to contact one widening surface (first widening surface) 111 of the pair of widening surfaces 111, 112. Thereafter, by closing the lid body 5 relative to the frame body 4, the sealing material 8 is also brought into contact with the other widening surface (second widening surface) 112 of the pair of widening surfaces 111, 112 as shown in FIGS. 1 and 3. This allows the seal material 8 to come into contact with both of the pair of widened surfaces 111, 112 at the same time as closing the cover body 5 on the frame body 4.

[0025] Next, a modified example of the underground structure cover 1A will be described. Figure 6 is a cross-sectional view of a main part of the underground structure cover 1B according to the modified example. Figure 7 is a schematic diagram for explaining the configuration of the flow path 7 provided in the underground structure cover 1B. The modified underground structure cover 1B mainly differs from the underground structure cover 1A shown in Figures 1 to 4 in that the sealing material 8 is located between the load transmission part 20 and the load support part 70. The load transmission part 20 in this example includes a first flat surface 21, a first recess 130 recessed toward the second direction D12 relative to the first flat surface 21, and a first connection surface 22 connected to the connection part 50. In addition, the load-bearing portion 70 in this example includes a second flat surface 71, a second recess 140 that is recessed toward the first direction D11 relative to the second flat surface 71 so as to form, together with the first recess 130, an accommodation space 150 that accommodates the sealing material 8, and a second connecting surface 72 that is continuous with the deformation-inducible portion 60.

[0026] The first recess 130 includes a first bottom surface 131 and a pair of lid side wall surfaces 132, 133 (first lid side wall surface 132 and second lid side wall surface 133) rising from the first bottom surface 131 toward the first direction D11. The first lid side wall surface 132 faces the second lid side wall surface 133. The first lid side wall surface 132 is continuous with the first flat surface 21, and the second lid side wall surface 133 is continuous with the first connecting surface 22. The second recess 140 includes a second bottom surface 141 and a pair of frame side wall surfaces 142, 143 (first frame side wall surface 142 and second frame side wall surface 143) rising from the second bottom surface 141 toward the second direction D12. The first frame side wall surface 142 faces the second frame side wall surface 143. The first frame side wall surface 142 is continuous with the second flat surface 71, and the second frame side wall surface 143 is continuous with the second connecting surface 72.

[0027] The flow path 7 includes a first flow path 160 having a first flow path width T1, a second flow path 170 located downstream of the first flow path 160 and having a second flow path width T2 larger than the first flow path width T1, and a connecting flow path 180 connecting the first flow path 160 and the second flow path 170. The connecting flow path 180 includes a pair of widening surfaces 181, 182 (first widening surface 181 and second widening surface 182) that widen toward each other to a third flow path width T3 larger than the first flow path width T1, thereby widening the flow path width. The first widening surface 181 is continuous with the first bottom surface 131 of the first recess 130 of the lid 5, and the second widening surface 182 is continuous with the second bottom surface 141 of the second recess 140 of the frame 4. In this example, first widening surface 181 is formed by first lid side wall surface 132. In addition, second widening surface 182 is formed by first frame side wall surface 142. First flat surface 21 includes a first connecting portion 161 that continues to first widening surface 181, and second flat surface 71 includes a second connecting portion 162 that continues to second widening surface 182.

[0028] Second flow path 170 is formed in the gap between first bottom surface 131 and second bottom surface 141, and second flow path width T2 is the distance between first bottom surface 131 and second bottom surface 141. Third flow path width T3 of connection flow path 180 is the distance between the intersection of first bottom surface 131 and first lid side wall surface 132 and the intersection of second bottom surface 141 and first frame side wall surface 142. In this example, third flow path width T3 is equal to second flow path width T2, and connection flow path 180 and second flow path 170 are connected with the same flow path width.

[0029] The sealing material 8 includes a first sealing portion 122 arranged to contact both of the pair of widening surfaces 181, 182, a second sealing portion 123 arranged to contact the second lid side wall surface 133 and the second frame side wall surface 143, and a third sealing portion 124 arranged to contact the first bottom surface 131 of the first recess 130 and the second bottom surface 141 of the second recess 140.

[0030] According to this underground structure cover 1B, the connecting flow path 180 connecting the upstream first flow path 160 and the downstream second flow path 170 includes a pair of widening surfaces 181, 182 that widen toward a flow path width (third flow path width T3) larger than the first flow path width T1, i.e., that widen in both directions relative to the first flow path 160. Therefore, by bringing the sealing material 8 into contact with both of the pair of widening surfaces 181, 182, the sealing material 8 can be arranged so that it extends beyond the first flow path width T1 and protrudes on both sides from the first flow path 160. This improves the blocking effect of the flow path 7, and as a result, it is possible to prevent the liquid material W flowing in from the road surface RS from seeping into the underground structure 2.

[0031] Furthermore, in this underground structure cover 1B, the load transmission portion 20 includes a first flat surface 21, and the load support portion 70 includes a second flat surface 71 disposed across the first flow path width T1 from the first flat surface 21. This allows the two flat surfaces 21, 71 to be disposed opposite each other in the load transmission path along which repeated loads caused by the movement of a vehicle or the like are transmitted, making it easy to reduce the first flow path width T1. This allows the sealing material 8 to come into contact with the pair of widened surfaces 181, 182 immediately downstream of the reduced first flow path 160. This allows the sealing material 8 to be made smaller, and the use of a compact sealing material 8 can efficiently improve the blocking effect of the flow path 7.

[0032] Furthermore, in this underground structure lid 1B, by disposing the sealing material 8 in the storage space 150 formed by the first recess 130 and the second recess 140, the sealing material 8 can be brought into contact with the bottom surfaces 131, 141 of the recesses 130, 140, the second lid side wall surface 133, and the second frame side wall surface 143 in addition to the pair of widening surfaces 181, 182. Therefore, even if the liquid material W leaks from the contact portion 122a between the first widening surface 181 and the first seal portion 122 on the first lid side wall surface 132 of the recess 130, further penetration of the liquid material W can be suppressed by the contact portion 124a between the bottom surface 131 of the recess 130 and the third seal portion 124 and the contact portion 123a between the second lid side wall surface 133 facing the first widening surface 181 and the second seal portion 123. Similarly, even if the liquid material W leaks out from the contact portion 122b between the second widening surface 182 and the first seal portion 122 on the first frame side wall surface 142 of the recess 140, further penetration of the liquid material W can be suppressed by the contact portion 124b between the bottom surface 141 of the recess 140 and the third seal portion 124, and the contact portion 123b between the second frame side wall surface 143 facing the second widening surface 182 and the second seal portion 123. Therefore, it is possible to provide a lid 1B for an underground structure that further improves the blocking effect of the flow path 7.

[0033] The present invention is not limited to the above-described embodiments and includes those defined in the claims. For example, one or more connecting flow paths connecting the first and second flow paths may be provided at any position in the flow path 7 formed in the gap between the frame 4 and the lid 5. However, by providing the first flow path in the load transmission path and providing the connecting flow path immediately downstream thereof, as in the above-described embodiment, the sealing material 8 can be made smaller, and the use of a compact sealing material 8 can efficiently improve the blocking effect of the flow path 7. Furthermore, although the above-described embodiments use terms such as "horizontal," "parallel," "vertical," "disc-shaped," "annular," "cylindrical," and "flat," these states are not required to be strictly defined. In other words, these terms allow for deviations in manufacturing accuracy, installation accuracy, and the like. [Explanation of symbols]

[0034] DESCRIPTION OF SYMBOLS 1A, 1B Lid for underground structure, 2 Underground structure, 3 Opening, 4 Frame, 5 Lid, 7 Flow path, 8 Sealing material, 10 Lid main body, 20 Load transmission portion, 21 First flat surface, 30 Protrusion, 50 Connection portion, 51 Recess, 52 Bottom surface, 53 First wall surface, 70 Load support portion, 71 Second flat surface, 90 First flow path, 91 First connecting portion, 92 Second connecting portion, 100 Second flow path, 110 Connecting flow path, 111 First widening surface (one widening surface of a pair of widening surfaces), 112 Second widening surface (the other widening surface of a pair of widening surfaces), 120 First sealing portion, 121 Second sealing portion, 122 First sealing portion, 160 First flow path, 161 First connecting portion, 162 Second connecting portion, 170 second flow path, 180 connecting flow path, 181 first widening surface, 182 second widening surface, C1 central axis, D1 first direction, D11 first orientation, D12 second orientation, D2 second direction, RS road surface, T1 first flow path width, T2 second flow path width, T3 third flow path width, W liquid body

Claims

[Claim 1] a frame body that forms an opening that connects the road surface and the underground structure; a lid supported by the frame so as to be openable and closable; a flow path formed in a gap between the frame body and the lid body when the lid body is closed on the frame body, through which the liquid material flowing in from the road surface flows; a seal material disposed in the flow path, The flow path includes a first flow path having a first flow path width; a second flow path located downstream of the first flow path and having a second flow path width greater than the first flow path width; a connecting flow path that connects the first flow path and the second flow path, the connecting flow path includes a pair of widening surfaces that widen toward each other toward a third flow path width that is larger than the first flow path width, thereby widening the flow path width; the sealing material includes a first sealing portion arranged to contact both of the pair of widening surfaces, The lid body includes a lid main body portion that can close the opening, a load transmission portion that transmits the load of the lid main body portion to the frame body, the frame includes a load support portion that supports the load of the lid body transmitted by the load transmission portion, the load transfer portion includes a first flat surface extending in a second direction perpendicular to a first direction parallel to a central axis of the opening, the load support portion includes a second flat surface disposed across the first flow path width from the first flat surface, the first flat surface includes a first connecting portion connected to one of the pair of widening surfaces, the second flat surface includes a second connecting portion connected to the other of the pair of widening surfaces, The lid body has a protrusion protruding from a first position of the lid main body portion in a first direction from the road surface side toward the underground structure side in the first direction; a connecting portion connecting the first flat surface and the protruding portion, the connection portion includes a recess recessed in a direction opposite to the first orientation with respect to the first flat surface, the recess includes a bottom surface formed at the first position and a wall surface rising from the bottom surface so as to face the protrusion, The wall surface includes the one widening surface, A cover for an underground structure, wherein the sealing material includes a second sealing portion positioned to contact the protrusion.

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