JPS6124595B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a joint for a culvert used in water supply and sewerage systems, public ditches, underground passages, etc. More specifically, it relates to a joint for a culvert used in water supply and sewerage systems, public ditches, underground passages, etc. This invention relates to an underdrain joint that suppresses harmful distortion.

(Prior art) In general, in the case of culverts for water supply and sewage systems, underground passages, public ditches, etc., which are buried in soft reclaimed land or ground with changing strata, the culvert structure is affected by uneven subsidence or relative displacement of the ground. In order to prevent this from occurring, cracks and water leakage may occur in the underdrain, and in some cases, the underdrain structure itself may be damaged.In order to prevent this, measures are taken to connect the underdrain by arranging flexible joints at key points.

Conventional flexible joints for culverts simply connect both ends of a cylindrical flexible member made of an elastic material such as rubber or synthetic resin or a variable shape material such as a thin iron plate or thin copper plate within the concrete frame of the opposing culvert opening. A flexible cylindrical member is installed along the inner circumferential surface of the culvert opening, spanning both culverts, and its ends are anchored to the concrete frame. However, a joint in which both ends of a cylindrical flexible member are simply buried in a concrete frame has the problem that it cannot follow large relative displacements between opposing underdrains, and also In the case of a joint with a flexible member installed, the flexible member may protrude into the inside of the culvert due to external water pressure such as groundwater or earth pressure, reducing durability, or if used in a culvert with running water, the flexible member may protrude into the interior of the culvert. There were problems such as damage caused by pieces of iron, wood, and boulders inside.

The present invention has been made to solve these problems, and provides a joint for underdrains that can absorb relatively large relative displacements of the underdrains to be connected, as well as improve durability and protect against boulders, etc. The purpose is to

(Means for Solving the Problems) In order to achieve the above object, the present invention forms a recess at the center of the underdrain body on each of the opposing end faces of a pair of underdrains to be connected, and recesses are formed in the end faces of both underdrains. a concave portion formed with a U-shaped cross section at both sides and a central portion, the interval between the outer surfaces of the side portion being larger than the interval between the culverts at the inner and outer peripheral positions of the building frame, and the central portion of the U-shaped cross section; a flexible part that is thicker than the distance between the culverts at the inner and outer peripheral positions of the frame and has a shoulder part that slopes from the side part toward the center; A flexible member made of an elastic material such as rubber or synthetic resin is built in and has a mounting portion extending toward the conduit, and the outer side surface and shoulder portion of the flexible member are in contact with the wall surface of the recess of the underdrain. An elastic joint material is interposed between the culverts and inside the concave surface of the flexible member.

(Example) Hereinafter, an example of the underdrain joint of the present invention will be described with reference to the drawings.

In FIG. 1, 1 and 1' are a pair of underdrains to be connected. Although the illustrated example shows a culvert with a rectangular cross section, the cross-sectional shape is not limited to this, and may be other shapes, such as a circle, a bow shape, or a polygon. Furthermore, although the culvert is shown as being made of concrete, it may also be a segment-connected type culvert, an integral cylindrical type steel culvert, or the like. A cylindrical flexible member 2 made of an elastic material such as rubber or synthetic resin is arranged between the opposing end surfaces of the underdrains 1 and 1', and joint material is provided at the inner and outer circumferential positions of the flexible member 2. Filled.

Figure 2 shows a cross section of a joint for a culvert, and since it has a symmetrical structure in the joint axis direction, one member will be explained and the other member will be labeled with the reference numeral of the one member. By assigning a symbol with a dash to it, redundant explanation thereof will be omitted as necessary.

In Fig. 2, the underdrains 1 and 1' have recesses _{1a and 1a} ' in which the flexible member 2 is housed in the center of the end surface of the frame body, and the inner and outer peripheral positions of the recesses _1a and _1a ' are mutually arranged. They face each other with a distance D between them. Flexible member 2
has a flexible portion _2a having a U-shaped cross section, and attachment portions _2b , _{2b '} extending toward the inner depths of the underdrains 1, 1' at both ends of the flexible portion 2a. The flexible part _2a is composed of both side parts _2a - ₁ and _2a - ₂ . The distance between the outer surfaces of both sides 2 _{a - 1} , 2 _a - ₁ ′ of the flexible portion 2 a is larger than the distance D at the inner and outer peripheral positions of the culverts 1 and 1 ′, and The central portion 2 _{a - 2} of the portion 2 a is formed thicker than other portions so as to have a thickness m greater than the distance D between the inner and outer peripheral positions of the underdrains 1 and 1'. The central portion 2 _a - ₂ has a concave annular curved surface 2 _c curved on the concave side of the flexible portion 2 _a having the U-shaped cross section, and horizontal on the convex side of the flexible portion 2 _a having the U-shaped cross section. It has an annular horizontal surface _2d extending in the direction and shoulder surfaces 2e _{and 2e '} extending diagonally outward from both ends of the horizontal surface 2d. The shoulder surfaces 2 _e and 2 _e ′ are the recesses 1 _{a and 1} of the culverts 1 and 1′.
It is in contact with the inner surface of _a ′.

It is preferable that protrusions 2 _f and 2 _{f '} are formed in the portions of both sides 2 _a - ₁ and 2 _a - ₁ ′ of the flexible member 2 that are in contact with the end surface of the underdrain 1 . _f , 2 _f ′
If a projection 2 _f is provided on the end face of the culvert 1, a projection 2
A concave groove 1 _b is formed to receive the groove _f . Projection 2 _f
is tightly received in the concave groove _1b , and restrains the flexible portion _2a from sliding along the end surface of the underdrain 1 in the radial direction of the joint. In Figure 2, the protrusion 2 _f is on each side 2 _a
- ₁ , 2 _a - ₁ ', but this number does not need to be limited to one, and multiple pieces may be provided on each of the left and right outer surfaces. Good too.

As described above, in a preferred embodiment, protrusions are formed on the outer surface of each side of the flexible section having a U-shaped cross section of the flexible member, and the protrusions are tightly received in the concave grooves formed on the underdrain surface. The flexible part is supported so that it does not slide on the end face of the underdrain, which further improves the pressure resistance performance.In addition, the effective suspension length of the flexible member can be shortened, and it is possible to prevent external pressure such as groundwater pressure or internal water pressure. When internal pressure is applied, the pressure itself that acts inside the U-shaped flexible section can be effectively used to strengthen the suspension of the flexible member to the end surface of the underdrain, thereby further suppressing the occurrence of harmful strain. The engagement between the protrusion and the concave groove is also maintained by the joint filler inserted inside the flexible section with a U-shaped cross section, making it possible to maintain a stable state of engagement and ensure stable pressure resistance. It is possible to improve performance and suppress the occurrence of harmful distortion.

The attachment portion 2 _b of the flexible member 2 is fixed to the concrete frame by an anchoring fitting 4 fixed to reinforcing bars or a steel frame and an anchoring fitting 5 serving as a backing plate _.
After clamping and firmly tightening with tightening means 6 such as bolts and nuts, concrete is poured.

The joint materials 7 and 8 interposed between the end faces of the underdrains 1 and 1' and at the inner and outer peripheral positions of the flexible member 2 are elastic joint materials made of rubber, sponge, or the like. The joint material 8 is a flexible portion 2 having a U-shaped cross section of the flexible member 2.
The inside of the concave surface of _a is also filled, and also functions to prevent the protrusion 2 _f from leaving the concave groove 1 _b of the underdrain 1.

Fig. 2 shows a case in which the anchoring fitting 5 is made of a plate-like cross section, but in order to increase the rigidity of the anchoring fitting 5 and make the fixing firmer, the anchoring fitting 5 has a hook-shaped cross section as shown in Fig. 3. Metal fittings may be used.

In the examples shown in FIGS. 2 and 3, the flexible member 2 is installed so that its U-shaped flexible portion _2a opens outward from the joint, but as shown in FIG. Alternatively, it may be installed so as to open toward the inside of the joint. The example shown in FIG. 4 is suitable for cases where the internal pressure is high.

The operation of the underdrain joint having the above configuration will be explained. 2 and 3 show the normal state before any relative displacement occurs between the underdrains 1 and 1'. In this state, the flexible member 2 is built in between the end faces of the underdrains 1 and 1', and the joint materials 7 and 8 are interposed at the inner and outer periphery positions, so that the flexible member 2
The flexible member 2 is not directly exposed to external earth and sand or to boulders in running water inside, and the flexible member 2 is not damaged.

When external water pressure, such as groundwater, acts on the joint of an underdrain, the external water passes through the elastic joint material 8 to the flexible part 2.
The flexible member 2 enters the concave side of _a and receives pressure from inside the U-shaped cross-sectional flexible portion 2 _a , and the flexible member 2 tends to deform in the direction of expanding outward. Therefore, the side outer surface of the flexible portion 2 _a is in close contact with the end surfaces of the underdrains 1 and 1', and when the side outer surfaces are provided with protrusions 2 _f and 2 _f ', the protrusions 2 _f and 2 _f ′ are received in the concave grooves 1 _b and 1 _b ′ on the end faces of the underdrains 1 and 1′, and a state of close reception is automatically maintained, and each side portion 2 _a ― ₁ and 2 _a - ₁ ' is shortened, thereby reducing the internal stress on the flexible member 2 due to external pressure loads such as external water pressure, and preventing excessive deformation or damage to the flexible member 2.
Unreasonable distortion is prevented from occurring. In addition, since the flexible member 2 has a thickened central portion 2 _a - ₂ , it functions as a highly rigid annular ring, increasing pressure resistance and allowing the flexible member 2 to move in the radial direction of the joint. This prevents the flexible member 2 from being significantly deformed or causing excessive strain to the flexible member 2. Furthermore, since the thickness m of the central portion 2 _a - ₂ of the flexible member 2 is larger than the distance D between the underdrains 1 and 1', the central portion 2 _a - ₂ is connected to the under conduits 1 and 1'.
There is no possibility that the flexible member 2 will enter the gap at the inner circumferential position between 1' and be significantly deformed inward in the radial direction of the joint, and therefore no unreasonable strain will occur in the flexible member 2. Also,
The distance between the outer surfaces of both sides of the flexible member 2 is as follows:
The flexible member central portion 2 _a - ₂ is formed to be larger than the distance D at the inner and outer circumferential positions between the culverts 1 and 1', and the flexible member central portion 2 a - 2 is connected to the recesses 1 a and 1 _a ' of the underdrains 1 and 1 _' and the shoulder surfaces 2 _e and 2 _e ′, the load due to external pressure is supported and pressure resistance is improved, and the flexible member 2 is prevented from escaping from the underdrain recesses 1 _a and 1 _a ′, which is harmful to the flexible member 2. This prevents distortion from occurring.

On the other hand, when the internal water pressure is higher than the external water pressure, pressure builds up from the convex side of the flexible portion 2 _a and the flexible member 2
tends to deform outward in the radial direction of the joint, but even in this case, the thickened central portion 2a _{- 2} of the flexible member 2 acts as a reinforcing ring, and the flexible member 2
In addition to preventing deformation and generation of harmful strain, when the protrusions 2 _f , 2 _f ′ are provided, the protrusions 2 _f , 2 _f ′
The engagement between the grooves 1 _b and 1 _b ′ also prevents harmful deformation. Note that the engagement between the projections 2 _f , 2 _f ′ and the concave grooves 1 _b , 1 _b ′ can be easily removed because the elastic joint material 8 is inserted into the concave side of the flexible member 2 . There isn't. Moreover, the flexible member 2 has a central portion 2 _a
- ₂ , and the thickness m of the central part 2 _a - ₂ is the distance D between the culverts 1 and 1' at the inner and outer peripheral positions of the culverts.
Since it is made larger, the flexible member 2 will not escape from the gap on the outer circumferential side between the underdrains due to internal pressure loads such as internal water pressure, and will not cause harmful deformation.

The watertightness of the joint is completely ensured because the attachment parts 2 _b and 2 _b ′ of the short cylindrical flexible member 2 are embedded and fixed in the concrete of the culverts 1 and 1 ′. The engagement between the projections 2 _f and 2 _f ′ of 2 and the concave grooves 1 _b and 1 _b ′ on the end faces of the underdrains 1 and 1′, and the engagement between the outer surface of each side of the flexible member 2 and the end faces of the underdrains 1 and 1′ It is also maintained by close contact.

The effect of the joint of the underdrain in FIG. 4 is simply that the effect of internal and external pressure is reversed from that in FIGS. 2 and 3, so a description thereof will be omitted.

FIG. 5 shows a situation where uneven settlement occurs between the pair of underdrains 1 and 1' to be connected in a direction perpendicular to the axis of the joint, and the joint of the underdrains reaches its permissible limit. In this state, the central part 2 _a of the flexible member 2 -
₂ is thickened, and the thickness m of the central part 2 _a - ₂ is the distance D between the culverts 1 and 1' at the inner and outer peripheral positions of the culverts.
The larger size works effectively,
Harmful deformation and distortion of the flexible member 2 is prevented from occurring. In addition, when protrusions 2 _f and 2 _f ′ are provided,
One of the left and right protrusions 2 _{f and} 2 _f ′ of the flexible member 2, for example 2 _f ′, separates from the concave groove 1 _b ′ on the end face of the underdrain 2′, but the other protrusion 2 _f Since it is engaged with the concave groove _1b on the end face of the underdrain 1,
Excessive deformation of the flexible portion 2 _a is prevented. Even in this state, the flexible member 2 is mostly located between the end faces of the underdrains 1 and 1', and is hardly exposed to earth and sand or running water in the underdrains.

Figure 6 shows a case where uneven settlement occurs between the culverts 1 and 1' to be connected in the opposite direction to that in Figure 5, but since the effect is similar to that in Figure 5, detailed explanation will be omitted. .

Figure 7 shows the protrusion 2 that has separated from the concave groove _1b ' on the end face of the underdrain 1' and reversed in the state shown in Figure 5.
This figure shows the state in which _f ' is received in another concave groove _1c on the end face of the other underdrain 1 in its reversed position. In this way, turn the inverted protrusion 2 _f ′ into the concave groove 1 again.
The deformation of the flexible member 2 is further suppressed by receiving it at _c , and the generation of harmful strain is suppressed, so that the durability of the flexible member 2 is increased.

(Effect of the invention) When using the underdrain joint according to the present invention, the cross section U
A flexible member with a letter-shaped flexible part is built into the center of the underdrain body between the end faces of the pair of underdrains to be connected, and joint material is inserted at the inner and outer circumferential positions of the flexible member, making it possible to prevent large relative displacement between the underdrains. In addition to being able to absorb the water, it is possible to prevent the flexible member from being damaged by dirt inside and outside the culvert or by boulders in flowing water. The built-in structure of the flexible member between the end faces of the underdrain can be maintained even when a relative displacement occurs between the underdrains.

Further, the distance between the outer surfaces of both sides of the flexible member is formed to be larger than the distance between the underdrains at the inner and outer circumferential positions of the underdrain frame, and the thickness of the central portion of the flexible member is greater than the distance between the underdrains at the inner and outer circumferential positions of the structure. Since it is formed with a greatly increased thickness, when pressure is applied, the central shoulder surface is supported by the concave part of the underdrain end face, improving pressure resistance, and the central part acts as a reinforcing ring. By functioning as well, it is possible to improve the pressure resistance performance. Further, since the central portion is prevented from entering the gap D at the inner and outer peripheral positions of the underdrain and being deformed, it is possible to suppress the occurrence of harmful strain in the flexible member.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an underdrain equipped with the underdrain joint of the present invention, and FIG. 2 is a sectional view taken along the line - in FIG. 1, showing an embodiment of the underdrain joint of the present invention. Figure 3 is a sectional view of the state before relative displacement occurs between the culverts, and Figure 4 is a sectional view of the joint of the culvert with a different anchoring part fixing method before relative displacement occurs between the culverts. , of an underdrain joint in which the direction of the U-shaped cross section of the flexible member is reversed from that in the example shown in FIG.
Fig. 5 is a cross-sectional view of the joint of the culvert in Fig. 2 before relative displacement occurs between the culverts, and Fig. 6 is a state diagram of the culvert in Fig. 2 before relative displacement occurs between the culverts. FIG. 7 is a sectional view of the joint in a state where a relative displacement occurs between the underdrains in the direction opposite to that shown in FIG. 5, and FIG. FIG. 3 is a cross-sectional view when a concave groove is formed. 1, 1'...Drain, 1 _a , 1 _a '... Concavity, 1 _b , 1 _b '...
Concave groove, 2...Flexible member, _2a ...Flexible part, _2b , 2
_b ′...Mounting part, 2 _a - ₁ , 2 _a - ₁ ′...Side part, 2 _a - ₂ ...Central part, 2 _c ...Concave annular curved surface, 2 _d ...Annular horizontal surface, 2 _e , 2 _e ′... Shoulder surface, 2 _f , 2 _f ′...protrusion, 3...
Reinforcing bars, steel frames, 4, 5... Anchor fittings, 6... Tightening means,
7, 8...Glut material.

Claims (1)

[Claims] 1. A recess is formed at the center of the underdrain body on each of the opposing end surfaces of a pair of underdrains to be connected, and a U-shaped cross section is formed at both sides and the center in the recess formed on both end surfaces of the underdrain. The distance between the outer surfaces of the parts is formed to be larger than the distance between the underdrains at the inner and outer circumferential positions of the building frame, and the center part of the U-shaped cross section is thickened to be larger than the distance between the underdrains at the inner and outer circumferential positions of the building body, and the side part It is made of an elastic material such as rubber or synthetic resin, and has a flexible part with a shoulder part that slopes toward the center, and mounting parts that extend toward the back of the culvert at both ends of the flexible part. Built-in flexible member,
Moreover, the outer side surface and shoulder portion of the flexible member are provided in contact with the wall surface of the recess of the underdrain, and an elastic joint material is interposed between the underdrains and inside the concave surface of the flexible member. fittings.