JP2006144534A - Joint structure of underground concrete structure and execution method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure of an underground concrete structure which can be easily executed, which has simple constitution, and which can obtain favorable cut off properties. <P>SOLUTION: Water barrier rubber 21, which connects both of the joint slopes 11A, 11A' to each other, is arranged in the interior of the joint space 12 of a joint part 20. The joint space is surrounded by the joint slopes 11A, 11A', and has a triangle cross section. Then the joint slopes 11A, 11A' are formed on the outer peripheral edges of both of the shutterings 11, 11' respectively. Then a retaining filler 22 filled in the space on the outer peripheral side of the water cut off rubber is arranged at least on the undersurface of the shutterings. Furthermore, a joint material 24 is arranged between the end surfaces of the shutterings 11, 11' disposed adjacnet and opposed to each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a joint structure that is provided at a predetermined interval in the extending direction of an underground concrete structure such as a joint groove and connects the concrete structures on both sides so as to be relatively displaceable while maintaining water inside and outside, and a construction method therefor.

  For example, underground concrete structures such as underdrains constructed in the ground such as common trenches have joints interposed at predetermined intervals in the extending direction, and the temperature changes of the concrete structures on both sides while water is stopped inside and outside It is configured to allow relative displacement such as expansion and contraction due to the like.

  As such a joint structure, for example, as disclosed in Patent Document 1, a water stop plate is interposed between the opposing end surfaces of the concrete structure, and as disclosed in Patent Document 2, at the opposite end of the concrete structure. There are those in which a flexible water-stopping member made of an elastic material such as rubber or synthetic resin is watertightly attached between the inner peripheral portions of the frame bodies provided.

The water stop plate shown in Patent Document 1 is driven into concrete when constructing a concrete structure, and the anchor bolt provided integrally with the frame body in Patent Document 2 is driven and fixed when the concrete is placed. .
JP-A-9-144148 JP-A-10-88647

  However, since the water stop plate of Patent Document 1 and the anchor bolt of the frame body of Patent Document 2 are arranged at the center or inner peripheral side of the wall thickness, it is difficult for the surrounding air to escape during concrete placement, However, there was a problem that air pockets and jumpers were easily generated. It is difficult to confirm, and if an air pocket or jumper occurs, water may leak through it and the water stoppage may break down.

  This invention is made | formed in view of the said problem, Comprising: It aims at providing the joint structure of the underground concrete structure which can obtain favorable water stop with a simple structure, and its construction method.

  The joint structure of an underground concrete structure according to the first aspect of the present invention that achieves the above object is provided at predetermined intervals in the extending direction of the underground concrete structure so that the concrete structures on both sides are kept relative to each other while keeping the water inside and outside. A joint structure that is connected so as to be displaceable, and that is opposed to each other in a joint space having a triangular cross-section extending on the outer periphery surrounded by joint slopes of a predetermined angle formed on the outer peripheral edge of the opposing concrete structure. A flexible waterproofing member that connects joint slopes, and a holding and filling member that fills a space on the outer peripheral side of the flexible waterproofing member at least on the lower surface side of the concrete structure. A fixed plate portion having a predetermined width is formed from an elastic material as a cross-sectional shape extending obliquely at an angle corresponding to the joint slope from both outer edges of the character-shaped bent portion, and the left The fixing plate portion is provided by being bonded to the joint slope through an adhesive member, and the holding and filling member has an inner surface that substantially matches the outer surface of the flexible water blocking member, and the outer surface is the outer surface of the concrete structure. It is characterized by being formed of an elastic material as a cross-sectional shape that is substantially flush with.

  In this configuration, water is stopped by bonding the fixing plate portion of the flexible water-stopping member to the joint slope by the adhesive member, and the acting external water pressure presses the fixing plate portion against the joint slope to stop the water. When the concrete structures on both sides are displaced, the bent portion is elastically deformed while maintaining a water-stopping state.

  The invention according to claim 2 is characterized in that the distal end edge of the fixed plate portion of the flexible waterstop member is a lip portion whose outer surface is slanted with a predetermined gradient and whose thickness is gradually reduced.

  With this configuration, the lip portion is more closely attached to the joint slope by the external water pressure, and a large water stop effect is obtained.

  According to a third aspect of the present invention, at least on the lower surface side of the concrete structure, a pin for preventing the flexible water-proof member from shifting is partially circumferentially directed to the left and right fixing plate portions of the flexible water-proof member. The pin is inserted into and fixed to pin insertion holes formed at predetermined intervals, and the remainder is fixed to the concrete structure inside the joint slope.

  According to a fourth aspect of the present invention, there is provided a plate-like base portion extending in the circumferential direction so as to protrude from the left and right fixed plate portions of the flexible water blocking member toward the joint slope side at least on the lower surface side of the concrete structure. And a plate-like anchor portion for preventing the displacement of the flexible water-stopping member, which is formed at the tip of the base portion, to be formed integrally with the left and right fixing plate portions.

  The invention according to claim 5 is characterized in that notches for venting air are formed in the plate-like anchor portion at predetermined intervals in the circumferential direction.

  The invention according to claim 6 is characterized in that the thickness of the bent portion of the flexible waterstop member is larger on the opposite end side than on the bent tip.

  The invention according to claim 7 is the construction method of the joint structure, in which the bent portion is formed on the end form forming the end face of one of the opposing concrete structures before placing the concrete to construct the underground concrete structure. The flexible water-stopping member is placed in a predetermined position in advance, and the holding and filling member is placed on the outer peripheral side, and then concrete is placed.

  According to this construction method, the fixed plate portion of the flexible water-stopping member functions as a mold and forms a joint slope.

  According to the joint structure of the underground concrete structure of the invention of claim 1, at least the lower surface side of the concrete structure in the joint space having a triangular cross section extending on the outer peripheral side formed in the connection outer peripheral portion of the opposing concrete structure In this embodiment, a flexible water-stopping member and a holding and filling member that fills the space on the outer periphery thereof are disposed, and the fixing plate portion of the flexible water-stopping member is bonded to the joint slope by an adhesive member, thereby A double water-stop effect is obtained by bonding to the joint slope and the pressure contact of the fixed plate to the joint slope by external water pressure. It is possible to follow while keeping the water stop state by elastic deformation of the bent portion of the flexible water stop member. In addition, the joint slope is an inclined surface extending in the direction of the outer periphery, so that air can escape easily when placing concrete, and the occurrence of junkers can be suppressed, and the adhesive plate with the flexible water-stopping member has good adhesion. Can be obtained. Furthermore, since the joint slope is open to the outer peripheral side, the surface state can be confirmed from the outer peripheral side, and can be repaired if necessary. That is, it is possible to obtain good water stoppage with a simple configuration.

  Further, according to the invention of claim 2, the lip portion at the tip of the fixing plate portion of the flexible water-stopping member is easily brought into close contact with the joint slope due to the external water pressure, and a better water-stopping property can be obtained.

  According to the invention of claim 3, at least the lower surface side of the concrete structure is provided with a pin for preventing the displacement of the flexible waterproofing member, and a part of the pin is provided on the left and right fixing plate portions of the flexible waterproofing member. It is inserted and fixed in pin insertion holes formed at a predetermined interval in the circumferential direction, and the remaining portion is provided so as to be fixed to the concrete structure inside the joint slope. The displacement resists the tensile force applied to the fixed portion, reduces the shearing force generated in the adhesive member, prevents the flexible water-stop member from being displaced from the joint slope, and makes water stop even more reliable. .

  According to the invention of claim 4, at least on the lower surface side of the concrete structure, a plate shape extending in the circumferential direction so as to protrude from the left and right fixed plate portions of the flexible water blocking member toward the joint slope side. Since the plate-like anchor portion for preventing the displacement of the flexible water-stopping member provided with the base portion of the base portion and the bulging portion formed at the tip of the base portion is formed integrally with the left and right fixing plate portions, the opposing concrete structure The effect of resisting the tensile force applied to the fixed part due to the displacement between the objects and reducing the shearing force generated in the adhesive member is higher than that of the structure for preventing the displacement by the pin. The water stop can be made more reliable.

  According to the invention of claim 5, since the plate-like anchor portion is formed with notch portions for venting air at predetermined intervals in the circumferential direction, an air pocket is formed around the plate-like anchor portion. This can be effectively prevented.

  In addition, when a large external water pressure is applied to the flexible water-stopping member, the bending portion of the flexible water-stopping member is reversed, so that the tensile force applied to the fixed portion increases and the shearing force applied to the adhesive member increases. According to the invention of claim 6, since the bent portion of the flexible waterstop member has a thickness on the opposite end side larger than the thickness in the vicinity of the bent tip portion, a large external water pressure is applied to the flexible waterstop member. Even if it is applied, it is difficult for the bent part to be reversed. Therefore, it is possible to prevent an increase in the tensile force applied to the fixed part, and it is possible to further prevent the flexible water-stop member from being displaced from the joint slope. Can be made even more reliable.

  Furthermore, according to the construction method of the joint structure according to claim 7, before the concrete placement for constructing the underground concrete structure, the bending portion is put on the end form which forms the end surface of one of the opposing concrete structures. By arranging the flexible water-stopping member in a predetermined position in advance, placing the holding and filling member on the outer peripheral side thereof, and then placing concrete, the fixed plate portion of the flexible water-stopping member acts as a mold. Since the joint slope can be formed, it can be constructed very easily.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view of a joint groove which is an underground concrete structure to which one structural example of a joint structure of an underground concrete structure according to the present invention is applied, and FIG. 2 is a cross-sectional view taken along line AA of FIG.

  The joint groove 10 which is a concrete structure is formed by connecting box bodies 11 and 11 ′ having a rectangular cross-sectional shape and a predetermined length by a joint portion 20 which is a structural example of the joint structure according to the present invention. It is constructed by using the joint part 20 on the upper surface of the leveled concrete 1 (not shown in FIG. 1) by an in-situ casting method, with a joint portion 20 being inserted at predetermined lengths (each box) by the open-cut method, and after completion It will be buried back into the ground at a depth.

  As shown in FIG. 3 (A), which is an enlarged view of the portion X in FIG. 2 (enlarged cross-sectional view on the lower surface side), the joint portion 20 is formed in a chamfered shape on the outer peripheral edges of both boxes 11 and 11 ′. A water stop rubber 21 as a flexible water stop member for connecting the joint slopes 11A and 11A 'is disposed in a joint space 12 having a triangular cross-section extending on the outer peripheral side surrounded by the joint slopes 11A and 11A'. In addition, a holding and filling member 22 is disposed on the outer peripheral side, and a joint material 24, for example, a steel plate with rubber lining, is interposed between the end faces of the adjacent opposing boxes 11 and 11 '. Yes. Moreover, the outer periphery of this joint part 20 is covered with the protective plate 25 except for the lower surface in contact with the leveled concrete 1 which is the installation surface.

  The angles of the joint slopes 11A and 11A ′ formed on the outer peripheral edges of the boxes 11 and 11 ′ are set to 45 ° in the present configuration example, and therefore the apex angle of the joint space 12 is 90 °. . Although this angle can be changed as appropriate, a range of 60 ° to 150 ° is preferable in order to prevent air from being easily removed when concrete is placed and to prevent the occurrence of air pockets or jumpers.

  As shown in the sectional view of the single body in FIG. 4, the water-stopping rubber 21 is fixed to each of the left and right end edges of the bent portion 21A having a U-shaped cross section that opens to the inner surface side (upper side in FIG. 4). The plate portion 21B is formed of a flexible material such as rubber or synthetic resin in a shape extending obliquely on the outer peripheral side (lower side in FIG. 4). The slit portion 21S has a predetermined depth inside the bent portion 21A and a predetermined depth. Further, the left and right fixing plate portions 21B have a V-shape that opens to the outer surface side (lower side in FIG. 4) at an angle (90 °) equal to the apex angle of the joint space 12, and the tips thereof are on the outer peripheral side. The lip portion 21L is sharpened with an inclined surface. The waterproof rubber 21 is formed with a substantially uniform thickness except for the lip 21L.

  As shown in FIG. 3 (A), the water-stopping rubber 21 has an inner surface (upper surface in FIGS. 3 and 4) of the left and right fixing plate portions 21B as an adhesive member. The sheet 11 is bonded to the joint slopes 11A and 11A 'of the boxes 11 and 11' on both sides via the sheet 23 to connect the boxes 11 and 11 'on both sides, and the joint material 24 is covered with a double-sided butyl sheet. , 11 '. The bonding of the fixing plate portion 21B to the joint slopes 11A and 11A ′ is not limited to the butyl rubber sheet, but may be another adhesive.

  As shown in FIG. 5A, the holding and filling member 22 has a shape substantially corresponding to the irregularities on the outer surface side of the water-stopping rubber 21, and the outer surface of the holding and filling member 22 has an inner surface 22 </ b> A of the water-stopping rubber 21. It is formed of an elastic material such as sponge rubber in a flat shape that is flush with the outer surfaces of the boxes 11, 11 'when fitted to the outer surface. That is, on the inner surface, a convex portion 22A that fits between the bent portion 21A of the water-stopping rubber 21 and the fixing plate portion 21B is provided on the left and right, and a concave portion 22B that fits the bent portion 21A of the water-stopping rubber 21 is formed therebetween. It is what. The formation may be performed integrally with a mold or may be performed by separately forming and bonding the substrate portion 22 'and the convex portion 22A as shown in FIG.

  In the joint portion 20 having the above-described configuration, the left and right fixing plate portions 21B of the water-stopping rubber 21 are bonded to the joint slopes 11A and 11A ′ of the boxes 11 and 11 ′ on both sides by the butyl rubber sheet 23, respectively. , 11 '. Moreover, the external water pressure which acts from the outside presses the fixed plate portion 21B against the joint slopes 11A and 11A ′ and closely adheres to further improve the water stoppage. That is, a double water-stop effect can be obtained by bonding with the butyl rubber sheet 23 and pressure contact with external water pressure.

  Since the joint slopes 11A and 11A 'are inclined surfaces extending in the outer peripheral side, air can be easily removed when concrete is placed, and the occurrence of junkers can be suppressed, and the water tightness with good adhesion to the fixed plate portion 21B is good. Can be obtained. Moreover, the surface state can also be confirmed from the outer peripheral side, and it can be repaired if necessary.

  As shown in FIG. 3 (B), when the box bodies 11 and 11 'on both sides are displaced, the bent portion 21A of the water-stopping rubber 21 extends to maintain the water-stopping and allow it. At this time, since the holding and filling member 22 formed of an elastic material is also deformed, the extension deformation of the water blocking rubber 21 is not hindered.

  Next, the construction method which comprises the above joint parts 20 is demonstrated. First, as shown in FIG. 6 which is a diagram in the middle of construction corresponding to FIG. 2, the end mold 14 fixed to the inner mold 13 of the box 11 in the previous process and forming an end face is attached to the waterproof rubber 21. It fits into the slit portion 21S, supports the water blocking rubber 21 by the end form frame 14, covers the outer peripheral side with the holding and filling member 22, and further presses the outer periphery of the upper surface and side surfaces with the outer mold frame 15 (lower surface). Is not necessary because it is placed on the upper surface of the leveling concrete 1).

  As a result, the water-stopping rubber 21 becomes immovable, and the box 11 is constructed by placing concrete in this state. Thereafter, the end form 14 is removed, and the joint material 24 is bonded to the hardened concrete surface. Next, remove the form 13 and place it at the same position of the box 11 'to succeed the box 11'. And after concrete hardens | cures and removes the outer frame 15, the protection board 25 which prevents the invasion of earth and sand is provided in the outer surface of the joint part 20 except a lower surface.

  By such a construction method, the fixing plate portion 21B of the water blocking rubber 21 functions as a mold to form the joint slopes 11A and 11A 'of the boxes 11, 11'. After forming ′, there is no trouble of mounting the water stop rubber 21 and the holding and filling member 22, and workability is good. In particular, on the lower surface side, it is only necessary to place the holding and filling member 22 and the water-stopping rubber 21 on the leveled concrete 1, and the workability is extremely excellent. Although the surface states of the joint slopes 11A and 11A 'on the lower surface side cannot be confirmed, the fixing plate portion 21B of the water blocking rubber 21 has a mountain shape with a predetermined angle (60 ° -150 °). The joint slope 11A, 11A 'formed by 21B does not cause an air pocket or a jumper, and the fixing plate portion 21B and the joint slope 11A, 11A' can be brought into close contact with each other to obtain good water stoppage. .

  As shown in FIG. 7, the upper and side surfaces of the boxes 11 and 11 ′ are not formed with the joint inclined surfaces 11A and 11A ′ by the fixing plate portion 21B of the water blocking rubber 21 as described above. The joint slopes 11A and 11A 'are formed by the joint space mold 16 fixed to the joint 15 and the joint slopes 11A and 11A' are removed by removing the outer mold frame 15, the end mold frame 14, the mold frame 13 and the joint space mold 16 after placing the concrete. The water stop rubber 21 may be attached after checking the surface and retouching if necessary. In this case, the holding and filling member 22 is not attached to the upper surface and the side surface, and instead, it is sufficient to fill with sand. Also in this embodiment, since the joint space 12 opens to the outer peripheral side, the work can be easily performed from the outside.

  Further, as a method of forming the joint slopes 11A and 11A ′, as shown in a sectional view in a completed state in FIG. 8, when forming the boxes 11 and 11 ′, the joint slopes 11A and 11A ′ are formed at predetermined sites. The water stop rubber 21 may be attached after the box is cut to a size (box cutting portion 17), a mold is provided there, and the mortar 18 is filled to form the joint slopes 11A and 11A '. In this case as well, the holding and filling member 22 is not mounted on the upper surface and the side surface, but instead, the sand 28 may be filled. According to this embodiment, extremely smooth joint slopes 11A and 11A ′ can be formed, and a good water-stopping property can be obtained by being in close contact with the fixing plate portion 21B of the water-stopping rubber 21.

  FIG. 9 is an enlarged view of a joint portion similar to FIG. 3 (A) showing another embodiment of the present invention. In this embodiment, the same components as those in the embodiment of FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.

  In the embodiment of FIG. 9, a pin 26 for preventing the flexible water-stopping member from shifting is provided. Each pin 26 is made of a steel material or a plastic material, and a part thereof is inserted into pin insertion holes 27 formed at predetermined intervals in the circumferential direction in the left and right fixing plate portions 21 </ b> B of the water blocking rubber 21. It is fixed to the pin insertion hole 27 by an adhesive applied to the pin. The remaining portion of the pin 26 is fixed to the boxes 11 and 11 'inside the joint slopes 11A and 11A'.

  When constructing the joint of this embodiment, the pin insertion hole 27 is formed in the water-stopping rubber 21, the adhesive is applied to the pin 26, the butyl rubber sheet 23 is pasted, and the pin 26 is attached to the pin 26. Put concrete in the inserted state.

  In the embodiment of FIG. 3, the pin 26 can be attached not only on the lower surface side of the box but also on the upper surface side and the side surface, that is, the entire circumference of the box, but in the embodiment of FIGS. Since the concrete is placed before the flexible water-stopping member is disposed, the pins 26 cannot be attached to the upper surface side and the side surface side of the box, and are attached only to the lower surface side of the box without placing concrete. be able to.

  FIG. 10 is an enlarged view showing another embodiment of the joint of the present invention, and FIG. 11 is a side view of the joint viewed in the joint axial direction with the butyl rubber sheet 23 removed.

  In this joint, a plate-like base portion 29A that extends in the circumferential direction so as to protrude from the left and right fixed plate portions 21B of the water-stopping rubber 21 toward the joint slope side, and a bulge having a polygonal cross section formed at the tip of the base portion. A plate-shaped anchor portion 29 for preventing the flexible water-stopping member from being displaced is provided integrally with the left and right fixed plate portions 21B. As shown in FIG. 11, the plate-like anchor portion 29 is formed with notches 29C for venting air at predetermined intervals in the circumferential direction.

  In this embodiment, since the bulging portion 29B is formed in the plate-shaped anchor portion 29, the shear force generated in the adhesive member is reduced by resisting the tensile force applied to the fixing portion due to the displacement between the opposing concrete structures. Even when the bending portion is reversed by the external water pressure and a large tensile force acts on the fixed portion, the plate-shaped anchor portion 29 does not come out and the joint of the water blocking rubber 21 is effective. The displacement with respect to the slopes 11A and 11A ′ can be prevented more reliably, and the water stop can be further ensured. In addition, since the plate-like anchor portion 29 is formed with notched portions 29C for venting air at predetermined intervals in the circumferential direction, it is possible to effectively prevent the occurrence of air accumulation around the plate-like anchor portion 29. The adhesion between the fixing portion 21B of the water stop rubber 21 and the inclined slopes 11A and 11A 'can be improved.

  FIG. 12 is a diagram showing a modification of the embodiment of FIG. Also in this embodiment, as in the embodiment of FIG. 10, a plate-like anchor portion 30 comprising a plate-like base portion 30A and a bulging portion 30B is formed integrally with the fixed portion 21B. In FIG. 30, the bulging portion 30B has a circular cross section and is formed with a larger diameter than the bulging portion 29B having a polygonal cross section in FIG. Since the bulging portion 30B has a circular cross section, it has an advantage that it is easy to make by extrusion molding and has a good finish, and since it is made to have a large diameter, it has a large resistance to pulling and effectively prevents the anchor portion 30 from slipping out. be able to.

  Note that the bulging portion of the plate-like anchor portion can be formed into various shapes such as an ellipse in addition to the cross-sectional shape shown in FIGS.

  Further, in this embodiment, the bent portion 21A of the waterstop rubber 21 has a thickness t1 on the opposite end side (root side) larger than a thickness t2 in the vicinity of the bent tip portion. It is formed so that the thickness gradually increases toward the opposite end side. With this configuration, even when a large external water pressure is applied to the water stop rubber 21, the bent portion 21 </ b> A is not easily reversed. Therefore, an increase in tensile force applied to the fixed portion 21 </ b> B can be prevented, and the joint slope of the water stop rubber 21 can be prevented. The displacement with respect to 11A and 11A 'can be prevented more reliably, and water stop can be made even more reliable. Note that the same effect can be obtained when this configuration is applied not only to the embodiment of FIG. 12 but also to the waterproof rubber 21 of other embodiments such as FIG.

FIG. 1 is a perspective view of a joint groove which is an underground concrete structure to which one structural example of a joint structure of an underground concrete structure according to the present invention is applied. It is AA sectional drawing of FIG. (A) is an enlarged view of the joint part corresponding to X part of FIG. 2, (B) is a figure which shows the state from which the box body was spaced apart from it. It is sectional drawing of a water stop rubber. (A) is sectional drawing of a holding | maintenance filling member, (B) is the exploded view. It is sectional drawing of the common groove which shows a construction process. It is sectional drawing which shows the formation method of another joint slope. It is sectional drawing of the joint part by the joint slope formed by the other method. It is an enlarged view of the joint part of other embodiments of the present invention. It is an enlarged view of the joint part of other embodiments of the present invention. It is the side view which looked at embodiment of FIG. 10 in the joint axial direction. It is an enlarged view of the joint part of other embodiments of the present invention.

Explanation of symbols

10 Joint groove (underground concrete structure)
11, 11 'box 11A, 11A' joint slope 12 joint space 14 end form frame 20 joint part 21 water-stopping rubber (flexible water-stopping member)
21A Bent part 21B Fixed plate part 21L Lip part 22 Holding and filling member 26 Flexible water-proof member slip prevention pins 29, 30 Plate-like anchor part

Claims (7)

A joint structure that is provided at predetermined intervals in the extending direction of the underground concrete structure and connects the concrete structures on both sides so as to be relatively displaceable while keeping the water inside and outside,
A flexible water-stopping member for connecting the opposing joint slopes in a joint space having a triangular cross-section extending on the outer peripheral side surrounded by joint slopes of a predetermined angle formed on the outer periphery of the concrete structure facing each other; A holding and filling member that fills the space on the outer peripheral side of the flexible waterproofing member on at least the lower surface side of the concrete structure,
The flexible water blocking member is formed of an elastic material as a cross-sectional shape in which a fixed plate portion having a predetermined width extends obliquely at an angle corresponding to the joint inclined surface from both outer edges of a U-shaped bent portion. The left and right fixing plate portions are respectively bonded to the joint slope through adhesive members,
The holding and filling member is formed of an elastic material having a cross-sectional shape in which an inner surface substantially coincides with an outer surface of the flexible water blocking member and an outer surface is substantially flush with the outer surface of the concrete structure. Joint structure of underground concrete structure.   2. The underground concrete structure according to claim 1, wherein the distal end edge of the fixing plate portion of the flexible water blocking member is a lip portion whose outer surface is slanted with a predetermined gradient and whose thickness is gradually reduced. Joint structure.   At least on the lower surface side of the concrete structure, the pins for preventing the flexible water-stopping member from being displaced are partially formed on the left and right fixing plate portions of the flexible water-stopping member at predetermined intervals in the circumferential direction. The joint structure of an underground concrete structure according to claim 1 or 2, wherein the joint structure is inserted and fixed in a pin insertion hole, and the remainder is fixed to the concrete structure inside the joint slope. .   At least on the lower surface side of the concrete structure, a plate-like base portion extending in the circumferential direction so as to protrude from the left and right fixed plate portions of the flexible water blocking member toward the joint slope side surface and a tip of the base portion are formed. The plate-shaped anchor part for preventing a flexible water-stopping member deviation provided with a bulging part is formed integrally with the left and right fixing plate parts, according to any one of claims 1 to 3. Joint structure of underground concrete structure.   The joint structure for an underground concrete structure according to claim 4, wherein notches for venting air are formed in the plate-like anchor portion at predetermined intervals in the circumferential direction.   The underground concrete structure according to any one of claims 1 to 5, wherein the bent portion of the flexible water blocking member has a thickness on the opposite end side larger than a thickness in the vicinity of the bent tip portion. Joint structure. Before placing the concrete for constructing the underground concrete structure, the flexible water-stopping member is disposed in a predetermined position in advance by covering the bend mold forming the end surface of one opposing concrete structure with the bent portion. 7. The holding filling member is disposed on the outer peripheral side, and then concrete is placed, and the joint slope is formed by the fixed plate portion of the flexible water-stopping member. A method for constructing a joint structure of an underground concrete structure according to claim 1.

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