JPH09287192A - Flexible joint having smooth inner surface for culvert - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint which is smooth for the inner peripheries of culverts in which a recess or step is not produced between the culverts even if expansion or uneven settlement occurs between the culverts. SOLUTION: Flexible water-stop member press plates 4, 4' extending on the same plane as the inner peripheries 3a, 3a' of culverts 2, 2' so as to cover steps 3, 3' of the culverts 2, 2' are fixed to respective ends of the culverts 2, 2'. A flexible water-stop member 10 having a flat inner surface 10a is slidably disposed in a space 9 between the peripheries 3a, 3a' and between the plates 4, 4' and stopper member 11, 11' are fixed to the ends of the steps 3, 3', respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to
The present invention relates to a flexible joint for a culvert such as a cave.

[0002]

2. Description of the Related Art As shown in a sectional view of FIG. 12, a conventionally used joint has a step on a circumferential surface of a pair of rectangular culverts a and a 'facing each other. Part b,
b ', and the both ends d and d' of a short tubular flexible water-stopping member e which is made of a flexible member such as rubber or synthetic resin and has a constricted portion c bulging inward at the center. There is a type which is mounted on the peripheral surfaces of the steps b and b 'in a watertight manner to absorb the relative displacement of the culvert accompanied by uneven settlement of the ground and to stop water between these culverts. . Here, k is a joint material.

As a joint of the same type, there is a joint described in Japanese Patent Publication No. 63-58982, which is proposed by the present applicant. This joint, as shown in the cross-sectional view of FIG.
It is formed in a short tubular shape made of an elastic material such as rubber or synthetic resin, straddling stepped portions b and b ′ formed on the inner peripheral surfaces of the ends of a pair of opposed underdrains a and a ′, In addition, it has an annular constriction c that bulges toward the inner peripheral side in the center, and this constriction c
A flexible water blocking member e having anchoring flanges d, d 'extending from both sides of the anchoring flanges d, d',
Protective members f and f 'for preventing the flexible water-stopping member e from bulging in the axial direction are provided in a space formed between the step portions b and b' and the flexible water-stopping member e. It is arranged. G and g 'are frames having flanges h, h', j and j 'and end faces i and i', and k is a joint material.

[0004]

Since the joint shown in FIG. 12 has a structure in which the joint is recessed into the step portions b and b'with respect to the inner peripheral surface 1 of the underdrain, it is rotted in the underdrain such as sewer. There is an inconvenience that things, earth and sand, etc. are accumulated in the stepped portions b and b ', and that the common grooves and the like make the feet worse during passage during maintenance and inspection. When stretch or uneven settlement occurs between the culverts a and a ', the dents and steps between the culverts a and a'expand,
The above inconveniences increase.

[0005] In the joint shown in FIG. 13, the inner circumferential surface of the culvert is formed substantially flush with the inner circumferential surface of the culvert by the protective members f and f ′ arranged at the steps b and b ′ in normal times. Although the above-mentioned inconvenience can be prevented in the joint 12, it is unavoidable that a dent or a step occurs when the culverts a and a ′ elongate or unequally subside.

The present invention has been made in view of the problems of the above-mentioned conventional underdrain joint, and is smooth with respect to the inner peripheral surface of the underdrain at the time of installation, and also when stretch or uneven settlement occurs between the underdrain. However, it is an object of the present invention to provide an inner surface smooth flexible joint for an underdrain which can prevent a recess or a step from being formed between the underdrain.

[0007]

According to a first aspect of the present invention, there is provided an inner surface smooth flexible joint for an underdrain, which achieves the above object.
At the end of the pair of the underdrain, which is opposed to each other, the overhang is formed on the step portion formed so as to have a peripheral surface substantially parallel to the inner peripheral surface of the underdrain so as to be substantially flush with the inner peripheral surface of the underdrain. Flexible water stop member pressing plate that is extended and placed at the end of the underdrain, and rubber
Between the peripheral surface of the step and the flexible water stop member pressing plate, which is formed of a flexible member such as a synthetic resin and has a generally flat inner peripheral surface and both ends protruding outward. The projecting ends are held by the flexible water blocking member pressing plate and the peripheral surface of the step in a space formed in the space, and are slidable in the space so as to face each other. A flexible water blocking member that is disposed across both step portions of the underdrain, and the flexible water blocking member that is disposed at an end portion of the step portion that is closer to the opposing underdrain and that is flexible in cooperation with the flexible water blocking member pressing plate. And a stopper member for preventing the water blocking member from being separated from the stepped portion.

The joint according to the invention of claim 2 is
A short cylindrical frame body having an inner peripheral surface that is arranged on a step portion formed at the end portions of a pair of mutually facing underdrainages and that is substantially parallel to the inner peripheral surface of the underdrainage, and the inner peripheral surface of the underdrain And a flexible water-proof member pressing plate fixed to the end of the frame body so as to project over the stepped portion on a substantially flat surface and a flexible member such as rubber or synthetic resin The protruding end portion is formed in a space formed between the inner peripheral surface of the frame body and the flexible water blocking member pressing plate, the protruding end portion being formed in a short cylindrical shape having a peripheral surface and both ends protruding outward. The flexible water blocking member pressing plate and the inner peripheral surface of the frame body are sandwiched between the flexible water blocking member pressing plate and the inner peripheral surface of the frame body so as to be slidable in the space. The flexible water blocking member and the flexible water blocking member pressing plate fixed to the end of the frame near the opposing underdrain cooperate with the flexible water blocking member from the stepped portion. Characterized in that it comprises a stopper member for preventing removal.

The joint according to the invention of claim 3 is
The joint according to claim 1 or 2, wherein the flexible water blocking member has a water blocking lip portion formed so as to project from at least one of an inner side and an outer side of an outer peripheral side end of the projecting end. It is characterized by being provided.

The joint according to the invention of claim 4 is
The joint according to any one of claims 1 to 3, wherein the flexible water blocking member extends in the circumferential direction on at least one of the inner peripheral surface and the outer peripheral surface of the projecting end portion. It is characterized by having articles.

The joint according to the invention of claim 5 is
The joint according to any one of claims 1 to 4, wherein the width of the projecting end portion of the flexible water blocking member is larger than its height.

The joint according to the invention of claim 6 is
The joint according to any one of claims 1 to 5, wherein the projecting end portion of the flexible water blocking member is formed between the peripheral surface of the step portion and the flexible water blocking member pressing plate. It is characterized by having a height obtained by adding a compression allowance to the height of the space.

[0013]

According to the first aspect of the present invention, the flexible water blocking member holding plate extends substantially flush with the inner circumferential surface of the underdrain, and the flexible water blocking member has a flat inner circumferential surface. Therefore, at the time of installation of the joint, the flexible water blocking member pressing plate and the inner circumferential surface of the flexible water blocking member form a joint having a smooth inner surface substantially flush with the inner circumferential surface of the underdrain. In addition, when stretch displacement occurs between the underwater conduits, that is, when displacement occurs in the direction in which the joint between the adjacent underwater conduits expands, the flexible water blocking member is attached to the flexible water blocking member pressing plate and the step surface. The extension displacement between the underdrain can be followed by sliding in the space between the pressing plate and the peripheral surface of the stepped portion held by the. Therefore, the inner peripheral surface of the flexible water blocking member can maintain a flat surface, and can maintain a substantially same smooth surface as the inner peripheral surface of the culvert. When the extension displacement is large, the projecting end of the flexible water blocking member contacts the stopper member to prevent the flexible water blocking member from being separated from the stepped portion.

Further, even if uneven settlement occurs in the underdrain, the inner circumferential surface of the flexible water stop member remains flat, and the two underdrain are connected by the sloped inner circumferential surface of the flexible water stop member. Therefore, there is no sharp step unlike the conventional joint.

According to the second aspect of the invention, the same action as that of the first aspect of the invention is achieved, and in addition, the flexible water blocking member, the flexible water blocking member pressing plate and the stopper member are attached to the frame body. Since these components can be carried in and constructed in the factory in the form of being assembled in the frame body in advance in the factory, it is suitable when applied to the construction method in which the underdrain is constructed by concrete pouring on site.

According to the third aspect of the present invention, when the water stop lip is formed inside the outer peripheral side end of the projecting end of the flexible water stop member, the flexible water stop member is stopped against external water pressure. The water action is enhanced, and when the water shut lip is formed outside the outer peripheral side end, the water shut action of the flexible water shut member against the internal water pressure is enhanced.

According to the fourth aspect of the present invention, the water blocking projections are crushed to further enhance the water blocking action of the flexible water blocking member against the internal water pressure and the external water pressure.

According to the fifth aspect of the present invention, by making the width of the projecting end portion larger than the height, it is possible to prevent the projecting end portion from tilting forward at the time of displacement and stably maintain the water stop function. You can

According to the sixth aspect of the present invention, the protruding end portion has a height obtained by adding a compression allowance to the height of the space formed between the peripheral surface of the step portion and the flexible water blocking member holding plate. By having the height, the forward inclination of the protruding end portion at the time of displacement can be prevented more effectively.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show an embodiment in which the present invention is applied to a precast box culvert. FIG. 1 is a sectional view taken along line I-I of FIG. 2, which is a partial sectional view in normal times, and FIG. 2 shows a precast box culvert. Fig. 3 is a perspective view, Fig. 3 is a cross-sectional view showing a state of the joint in the case where extension displacement occurs between opposing underdrain pipes, and Fig. 4 is a cross-sectional view of the joint in the case where extension displacement and unequal settlement occur between opposing underdrain pipes. It is sectional drawing which shows a state.

In FIG. 2, reference numeral 1 denotes a underdrain joint according to the present invention, and 2 and 2'denotes an underdrain made of a precast box culvert. Opposite ends of the pair of culverts 2, 2 'are connected by a joint 1 according to the present invention.

This underdrain joint 1 is, as shown in FIG.
A stepped portion 3 is provided on the inner edge of the culvert 2, 2 '.
3'is formed, and the step portions 3 and 3'are culverts 2 and 2 '.
The inner peripheral surfaces 2a, 2a 'are formed with peripheral surfaces 3a, 3a' which are substantially parallel to each other.

A short tubular cylinder made of steel is provided so as to extend over the step portions 3 and 3'and extend substantially flush with the inner peripheral surfaces 2a and 2a 'of the underdrain 2,2'. Flexible water member holding plates 4, 4'are arranged. Since the flexible water blocking member holding plate 4'and its mounting structure are the same as the flexible water blocking member holding plate 4 and its mounting structure, the reference numerals used for the flexible water blocking member holding plate 4 and the like are denoted by dashes. The description of the flexible water blocking member pressing plate 4'and the like will be omitted.

As shown in the perspective view of FIG. 5 and the enlarged cross-sectional view of FIG. 6, the flexible water blocking member pressing plate 4 has a plurality of circular holes 4a formed at predetermined ends in the circumferential direction at fixed ends thereof. A cylindrical mounting member 5 is welded to the lower side of the circular hole 4a in the figure. The mounting member 5 has a bottom plate 5a (FIG. 6), and the anchor bolt insertion hole 5b is provided in this bottom plate 5a.
Are formed. Mounting member 5 of flexible water stop member pressing plate 4
Is arranged on the peripheral surface 3a of the end portion of the step portion 3 on the side opposite to the opposed underdrain, and the flexible water stop member pressing plate 4 is fixed by the anchor bolt 6 inserted through the bottom plate 5a of each mounting member 5. It is fixed to the step portion 3. A rubber plug 8 is loaded in the space above the hexagon socket bolt 7 at the head of the anchor bolt 6 inserted into each mounting member 5. Also, the middle mounting member 5 of the holding plate 4
A portion 4c on the opposite side of the overhanging portion 4b extending inwardly from is supported on the inner peripheral surface 2a of the underdrain 2.

In FIG. 5, the length L ₁ of the overhanging portion 4b of the flexible water blocking member pressing plate 4 projecting from the center of the mounting member 5 onto the stepped portion 3 is such that a smooth inner peripheral surface is secured and The length L ₂ is necessary to prevent the water member from being pulled out, and the length L ₂ of the portion 4c of the holding plate 4 in the opposite direction is an anchor when the external water pressure is applied to the overhanging portion 4b of the holding plate 4 from below in the figure. The length is necessary to reduce the bending force acting on the bolt 6.

In the illustrated embodiment, the mounting member 5 is formed in a cylindrical shape, but the present invention is not limited to this, and a large-diameter plate is fixed to the member having a U-shaped cross section or the bottom of the cylinder to enhance stability. Various types of mounting members such as the above can be used.

In the space 9 formed between the peripheral surface 3a of the stepped portion 3 and the flexible water retaining plate 4, the pair of opposed stepped portions 3, 3'of the underdrain 2, 2'are opposed to each other. A flexible water blocking member 10 made of a flexible elastic member made of rubber, synthetic resin, or the like is provided so as to straddle the above. As the material of the flexible water blocking member 10, a material having sufficient flexibility, elasticity and strength but having a low elongation is preferable. The flexible water blocking member 10 is formed in a short tubular shape having a generally flat inner peripheral surface 10a (that is, having no bulge portion or constriction portion) and both end portions 10b protruding outward, and in the space 9, the protruding end portion is formed. When 10b is clamped by the flexible water stop member pressing plate 4 and the peripheral surface 3a of the step portion 3 and expansion displacement or unequal subsidence occurs between the culverts 2 and 2 ', the space 9 is moved in the axial direction of the culvert. It can slide.

In order to enhance the water blocking function, the flexible water blocking member 10 is formed so as to project from the inside and outside of the outer peripheral side end of the projecting end 10b, as shown in FIG. It has water blocking lips 10c, 10d having a substantially triangular cross section. Further, two water-stop ridges 10e extending in the circumferential direction are formed on the inner peripheral surface of the protruding end portion 10b. In addition, a reinforcing cloth 10f is embedded in the flexible water blocking member 10 in order to increase its strength. The reinforcing cloth 10f may not be provided when the material of the flexible water blocking member 10 has sufficient strength. Further, in order to enhance the water blocking function, in addition to the water blocking lips 10c, 10d and / or the water blocking ridges 10e, or in place of these, in the circumferential groove formed on the outer peripheral surface of the projecting end 10b. Alternatively, 10 g of water-expandable rubber may be filled.

Assuming now that the width W of the projecting end portion 10b of the flexible water blocking member 10 is smaller than the height H, as shown in FIG. 14 (a), the displacement between the underdrain 2, 2 '. When it occurs, the flexible water blocking member 10 tries to slide in the space 9 in the direction of the arrow A, but the frictional force is inclined between the bottom surface of the projecting end and the peripheral surface 3a of the step portion, and moreover Since the projecting end portion 10b of the flexible water blocking member 10 is provided in the upper portion of the flexible water blocking member 10 rather than in the central portion thereof, when an external force acts during displacement, the flexible water blocking member 10 can be flexible The upper part of the water member 10 is pulled first,
As a result, the protruding end portion 10b is inclined forward in the traveling direction, which may cause water leakage in some cases.

Therefore, in the embodiment of FIG. 1, as shown in FIG. 7, the width of the projecting end portion 10b is made larger than the height H to provide a sense of stability, so that the projecting at the time of displacement as described above is caused. The end portion 10b is prevented from tilting forward, and the water stop function is stably maintained.

Further, in order to enhance the forward tilt preventing effect of the projecting end portion 10b of the flexible water blocking member 10 during such displacement, as shown in FIG. 8, the projecting end portion 1 of the flexible water blocking member 10 is shown.
0b may be formed to have a height obtained by adding the compression margin c to the height H of the space 9. Further, as shown in FIG. 9, not only the water stop ridge 10e may be formed on the inner peripheral surface of the projecting end 10b, but the water stop ridge 10h may be provided on the outer peripheral surface.

An annular stopper member 11 made of L-shaped steel is fixed by an anchor bolt 12 to the end portion of the step portion 3 on the side close to the opposed underdrain 2 '. Stopper member 11
Has a function of preventing the flexible water blocking member 10 from coming off the stepped portion 3 in cooperation with the flexible water blocking member pressing plate 4. Further, in the underdrain where internal water pressure is applied such as sewer, the flexible water blocking member 10
And has a function of preventing bulging and intrusion of earth and sand to the outer peripheral side of the flexible water blocking member 10 due to internal water pressure.

When L-shaped steel is used as the stopper member 11, the flexible water blocking member 10 may be damaged by the tip of the stopper member 11 when internal water pressure is applied to the flexible water blocking member 10. In order to prevent this, it is desirable that the tip of the stopper member 11 has a curved surface. Further, the contact surface with the flexible water blocking member 10 may be a smooth surface 11a as shown in FIG. 10 (a), or as shown in FIG. 10 (b) with a beat-shaped portion 11b or as shown in FIG. 10 (c). As described above, the arch surface 11c may be used. Further, in order to fix the stopper member 11 to the step portion 3, not only the anchor bolt 12 but also a plate anchor 19 as shown in FIGS. 10D and 10E may be used. Reference numeral 13 is a joint material made of sponge rubber or the like, which is filled in the joint between the opposed underdrain 2 and 2 '.

Next, the operation of the joint having the above structure will be described. The joint 1 is in the state shown in FIG. 1 when the joint is installed and in the normal condition in which the displacement such as the elongation displacement does not occur between the underdrain, and the flexible water blocking member 10 has the projecting ends 10b and 10b in the spaces 9 and 9 '. It is located at a position closest to the mounting members 5, 5'of the flexible water blocking member pressing plates 4, 4 '. The flexible water blocking member pressing plates 4, 4'and the flat inner circumferential surface 10a of the flexible water blocking member 10 allow the inner circumferential surfaces 2a, 2'of the underdrain 2, 2 '.
A smooth inner peripheral surface that is flush with a'is formed.

When an extension displacement occurs between the underdrain 2 and 2 ', as shown in FIG.
0, 10 and the pressing plates 4, 4'and the stepped peripheral surfaces 3a, 3
The arrow A in the space 9 resists the frictional resistance generated between the space a and
By following relative sliding in the direction, it follows the extension displacement between the underdrain. In this case, the flexible water blocking member 10 is provided with the underdrain 2, 2 '.
External water pressure is applied in the direction of arrow B through the joints that are widened between the flexible water blocking member 10 and the flexible water blocking member 10 to bulge toward the inner peripheral side. Depending on the external water pressure, the material and the compression allowance of the flexible water blocking member 10 are appropriately set so that the frictional force acting between the plates 4 and 4 and the step portion peripheral surfaces 3a and 3a 'has a sufficiently large value. It is possible to prevent the flexible water blocking member 10 from sliding in the direction of arrow A and bulging inward.

When the flexible water blocking member 10 slides in the direction of arrow A and the projecting ends 10, 10 reach the ends of the opposite ends of the underdrains 2, 2 ', the projecting ends 10, 10 are stoppers. By contacting the member 1111 'and restraining the projecting ends 10, 10 by the stopper members 11, 11' and the pressing plates 4, 4 ', the flexible water blocking member 10 is detached from the step portions 3, 3'. Is prevented.

When a combination of extension displacement and unequal subsidence occurs between the underdrain 2 and 2 ', the flexible water blocking member 10 moves in the space 9 as in the extension displacement as shown in FIG. Slide in the direction of arrow A. Also in this case, the inner peripheral surface 10a of the flexible water blocking member 10
Maintains a flat surface, and the two underdrains 2, 2 ′ are connected by the slope-shaped inner peripheral surface 10 a of the flexible water blocking member 10. Therefore, even in this case, it is possible to prevent a sharp step between the underdrain 2 and 2'as in the conventional joint.

Although the embodiment of FIG. 1 is designed to deal with the stretch displacement and unequal settlement between the underdrain 2, 2 ', in addition to this, the contraction displacement between the underdrain 2, 2' When dealing with it, the projecting ends 10b, 10 of the flexible water blocking member 10
By providing a predetermined gap between the b and the mounting members 5, 5'of the flexible water blocking member pressing plates 4, 4 ', it is possible to cope with such shrinkage displacement between the underdrain 2, 2'. it can.

FIG. 11 is a partial sectional view showing another embodiment of the present invention. This embodiment is suitable for a construction method in which an underdrain can be constructed by placing concrete at a construction site, and a flexible water blocking member, a flexible water blocking member pressing plate, and a stopper member are previously assembled in a frame at a factory. This is a joint assembly, and the joint assembly is carried into the field and constructed. 11, constituent elements that are the same as or similar to those in the embodiment of FIG. 1 are denoted by the same reference numerals as in FIG. 1, and description thereof will be omitted.

The joint 20 of FIG. 11 is a short tubular frame body 2 made of steel.
1 is provided. This frame 21 has a rising flange portion 21.
a and a falling flange portion 21b, and is formed in a shape that fits into the step portion 3 of the underdrain 2, and has an inner peripheral surface 21a that is substantially parallel to the inner peripheral surface 3a of the step portion 3 of the underdrain 2. ing. The flexible water stop member pressing plate 4 is fixed to the frame body 21 by a cap nut 23 attached to the attaching member 5, and the flat plate-like stopper member 11 is welded to the frame body 21. Anchor rods 24 are welded to the frame body 21 at predetermined intervals in the circumferential direction.

When this joint 20 is to be constructed, the joint 20 constructed as an assembly is carried into the site, installed at a predetermined position, and then concrete is poured on site to construct the underdrain 2. The operation of the joint 20 is performed by the flexible water blocking member 1
1 is substantially the same as the embodiment of FIG. 1 except that 0 slides in a space 9 formed between the holding plate 4 and the inner peripheral surface 21a of the frame 21. Is.

[0042]

As described above, according to the invention described in claim 1, the flexible water blocking member holding plate extends substantially flush with the inner peripheral surface of the underdrain, and the flexible water blocking member is flat. The inner surface of the flexible water stop member and the inner surface of the flexible water stop member have a smooth inner surface that is substantially flush with the inner surface of the underdrain when the joint is installed. Is formed.
In addition, when an extension displacement occurs between culverts, that is, when a displacement occurs in a direction in which joints between adjacent culverts expand,
The flexible water blocking member is held between the flexible water blocking member holding plate and the peripheral surface of the stepped portion. By sliding in the space between the pressing water plate and the peripheral surface of the stepped portion, the stretchable displacement between the underdrain is extended. Can follow. Therefore, the inner peripheral surface of the flexible water blocking member can maintain a flat surface, and can maintain a substantially same smooth surface as the inner peripheral surface of the culvert. When the extension displacement is large, the projecting end of the flexible water blocking member contacts the stopper member to prevent the flexible water blocking member from being separated from the stepped portion.

Further, even when uneven settlement occurs in the underdrain, the inner circumferential surface of the flexible water stop member remains flat, and the two underdrain are connected by the sloped inner circumferential surface of the flexible water stop member. Therefore, there is no sharp step unlike the conventional joint.

According to the second aspect of the present invention, the same action as that of the first aspect of the present invention is achieved, and the flexible water blocking member, the flexible water blocking member pressing plate and the stopper member are attached to the frame body. Since these components can be carried in and constructed in the factory in the form of being assembled in the frame body in advance in the factory, it is suitable when applied to the construction method in which the underdrain is constructed by concrete pouring on site.

According to the third aspect of the present invention, when the water stop lip is formed inside the outer peripheral side end of the projecting end of the flexible water stop member, the flexible water stop member is stopped against external water pressure. The water action is enhanced, and when the water shut lip is formed outside the outer peripheral side end, the water shut action of the flexible water shut member against the internal water pressure is enhanced.

According to the fourth aspect of the present invention, the water blocking projections are crushed to further enhance the water blocking action of the flexible water blocking member against the internal water pressure and the external water pressure.

According to the fifth aspect of the present invention, by making the width of the projecting end portion larger than the height, it is possible to prevent the projecting end portion from tilting forward at the time of displacement and stably maintain the water stop function. You can

According to the invention described in claim 6, the protruding end has a height obtained by adding a compression allowance to the height of the space formed between the peripheral surface of the step and the flexible water retaining member holding plate. By having the height, the forward inclination of the protruding end portion at the time of displacement can be prevented more effectively.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of an inner surface smooth flexible joint for an underdrain of the present invention.

FIG. 2 is a perspective view of a precast box culvert to which the joint of FIG. 1 is applied.

FIG. 3 is a cross-sectional view showing a state of the joint of the same embodiment at the time of extension displacement.

FIG. 4 is a cross-sectional view showing a state of the joint according to the same embodiment at the time of elongation and unequal settlement complex displacement.

FIG. 5 is a perspective view showing an example of a flexible water blocking member holding plate.

FIG. 6 is an enlarged cross-sectional view of a mounting member of the pressing plate.

FIG. 7 is a diagram showing details of a flexible water blocking member.

FIG. 8 is a diagram showing an example of a protruding end portion of a flexible water blocking member.

FIG. 9 is a view showing another example of the protruding end portion of the flexible water blocking member.

FIG. 10 is a sectional view showing various modifications of the stopper member.

FIG. 11 is a partial sectional view showing another embodiment of the joint of the present invention.

FIG. 12 is a partial sectional view showing an example of a conventional culvert joint.

FIG. 13 is a partial sectional view showing another example of a conventional culvert joint.

FIG. 14 is a cross-sectional view for explaining the forward tilting operation of the protruding end portion of the flexible water blocking member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joint 2, 2'Underdrain 3, 3 'Step portion 4, 4'Flexible water stop member pressing plate 10 Flexible water stop member 11, 11' Stopper member

Claims (6)

[Claims] 1. An inner peripheral surface of the underdrain formed so as to overhang on a step portion formed so as to have a peripheral surface substantially parallel to the inner peripheral surface of the underdrain at a pair of opposite ends of the underdrain. And a flexible water retaining member holding plate that extends almost on the same plane as that of the underdrain, and is made of a flexible member such as rubber or synthetic resin. The projecting end portion is formed in a short tubular shape having a step portion in the space formed between the peripheral surface of the step portion and the flexible water blocking member pressing plate and the flexible water blocking member pressing plate. A flexible water blocking member that is sandwiched by the peripheral surface of the portion and that is slidable in the space and that is disposed across both stepped portions of the pair of opposed underdrains,
A stopper member is provided at an end of the step portion on the side closer to the opposed underdrain, and a stopper member that cooperates with the flexible water blocking member pressing plate to prevent the flexible water blocking member from being separated from the step portion. An inner surface smooth flexible joint for an underdrain. 2. A short cylindrical frame body, which is arranged on a stepped portion formed at the ends of a pair of mutually facing underdrain and has an inner peripheral surface substantially parallel to the inner peripheral surface of the underdrain, From the flexible water stop member pressing plate fixed to the end portion of the frame body so as to project above the step portion on substantially the same plane as the inner peripheral surface of the underdrain, and the flexible member such as rubber or synthetic resin. In a space formed between the inner peripheral surface of the frame and the flexible water blocking member pressing plate, which is formed in a short tubular shape having a substantially flat inner peripheral surface and both ends protruding outward. The projecting end portion is held by the flexible water blocking member pressing plate and the inner peripheral surface of the frame body, and is slidable in the space so that the projecting end portions are formed on both the step portions of the pair of opposed underdrain. A flexible water blocking member arranged across the flexible water blocking member and a flexible water blocking member pressing plate that is fixed to an end of the frame near the opposing underdrain and cooperates with the flexible water blocking member holding plate. An inner surface smooth flexible joint for an underdrain, comprising a stopper member for preventing separation from a stepped portion. 3. The flexible water blocking member includes a water blocking lip portion formed so as to project from at least one of an inner side and an outer side of an outer peripheral side end of the projecting end. The inner surface smooth flexible joint for an underdrain according to claim 1 or 2. 4. The flexible water blocking member is provided with a water blocking ridge extending in the circumferential direction on at least one of the inner peripheral surface and the outer peripheral surface of the protruding end portion. An inner surface smooth flexible joint for an underdrain according to any one of 1 to 3. 5. The inner surface smooth flexible joint for an underdrain according to claim 1, wherein a width of the projecting end portion of the flexible water blocking member is larger than its height. 6. The protruding end portion of the flexible water blocking member has a compression margin at a height of the space formed between the peripheral surface of the step portion and the flexible water blocking member pressing plate. The inner surface smooth flexible joint for an underdrain according to any one of claims 1 to 5, which has an added height.