JPS5820348B2 - culvert joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a joint for an underdrain used in water supply and sewerage systems, public ditches, underground passages, etc. More specifically, the present invention relates to a joint for an underdrain that has improved pressure resistance and suppresses harmful elements of flexible members. It concerns joints.

In general, in culverts for water supply and sewerage systems, underground passages, public ditches, etc., which are buried in soft reclaimed land or ground with changing strata, the culvert structure ((cracks) may develop due to uneven subsidence or relative displacement of the ground. This can lead to water leakage and, in some cases, damage to the underdrain structure itself.In order to prevent this, measures are taken to connect the underdrains by providing flexible joints at key points.

Conventional flexible joints for culverts are installed within the concrete frame of the culvert opening by simply opposing both ends of a cylindrical flexible member made of an elastic material such as rubber or synthetic resin or a deformable material such as a thin iron plate or thin copper plate. It consists of a cylindrical flexible member that is buried and fixed in place, straddled over both underdrains along the inner circumferential surface of the culvert opening, and both ends of the cylindrical flexible member 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 a problem in that it cannot follow large relative displacements between opposing underdrains.

If there are joints in which a flexible member is installed along the inner circumference of the culvert, the flexible member may protrude into the culvert due to external water pressure such as groundwater or earth pressure, resulting in reduced durability or the possibility of running water. When used in culverts, there were problems such as damage caused by iron pieces, wood chips, boulders, etc. in flowing water.

In order to prevent these problems, the present invention uses a flexible member having a U-shaped flexible section in order to absorb the large relative displacement of the underdrain to be connected, and uses a flexible member having a U-shaped flexible section to absorb the large relative displacement of the underdrain. The object of the present invention is to provide a joint for an underdrain in which a flexible member is built into the center of the frame between the end faces of the underdrain in order to prevent damage caused by boulders and the like.

Furthermore, since the flexible member has a U-shaped cross section that is easy to bend, the present invention prevents the flexible member from deforming significantly and causing harmful distortion, or from bulging out between the end faces of the underdrain and causing damage. The purpose of the present invention is to provide a joint for an underdrain in which the distance between the outer surfaces of both sides of the flexible member is made closer to the distance between the underdrains at the inner and outer peripheral positions of the building frame, thereby improving pressure resistance and suppressing the occurrence of harmful distortion. shall be.

Further, the present invention provides projections on the outer surfaces of both sides of the flexible member, and the projections are closely inserted into the concave grooves formed on the end surface of the underdrain, thereby reducing the substantial hanging length of the flexible member. It is an object of the present invention to provide a joint for an underdrain which further increases the effect of improving pressure resistance and suppressing the occurrence of harmful strain.

Furthermore, in the present invention, the joint material located near the center of the flexible member is made of soft sponge rubber among the joint materials inserted into the inner and outer circumferential positions of the flexible member, thereby improving the quality of the underdrain. It is an object of the present invention to provide a dark joint that allows a flexible member to deform easily during relative displacement and further increases the effect of suppressing the generation of harmful strain in the flexible member.

Embodiments of the underdrain joint of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 and 1' are a pair of underdrains to be connected.

In the illustrated example, a culvert with a rectangular cross section is shown, but the cross-sectional shape is not limited to this, and may be other shapes such as a circle, a bow shape, a polygon, etc.

Furthermore, although the underdrain is shown as being made of concrete, it may also be a segment-connected underdrain, an integral cylindrical steel underdrain, or the like.

In this case, if necessary, a means such as an auxiliary segment (not shown) or the like is provided between the underdrains 1 and 1' to facilitate the installation of the underdrain joints. May be worn.

A cylindrical flexible member 2 made of an elastic material such as rubber or synthetic resin is arranged between the opposing end faces 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 the symbol, redundant explanation thereof will be omitted as necessary.

In Fig. 2, the underdrains 1, 1' have recesses or steps 1a, 1a' in which the flexible member 2 is housed in the center of the end surface of the frame, and the inner and outer peripheral positions of the recesses or steps 1a, Ia' are mutually arranged. to the interval D1. He is facing D2.

Dl and D2 are not necessarily equally spaced.

The flexible member 2 includes a flexible portion 2a having a U-shaped cross section and a flexible portion 2a.
It has attachment parts 2b, 2b' extending toward the inner depths of the underdrains 1, 1' at both ends thereof.

The flexible portion 2a consists of both end portions 2a-1, 2a-1' and a central portion 2a-2.
' and the central portion 2a-2 have a substantially uniform thickness.

The distance l between the outer surfaces of both sides 2a-1, 2a-1' of the flexible portion 2a is equal to the distance D1. D2 or more, and it is difficult to escape from the underdrain recess or stepped portions 1a and 1a' under normal conditions.

Further, on the outer surface of the transition part 2a-4 from the center part 2a-2 to the side part 2a-1 of the flexible part 2a having a U-shaped cross section, there is a shoulder surface 2a-3° 2a-3 having a tapered or curved surface. (The figure shows the case of a tapered surface.

) are formed, and these shoulder surfaces 2a-3, 2a-3'
are in contact with and supported by seating surfaces 1b and Ib' formed on the inner surfaces of the recesses or stepped portions 1a and 1a' at positions corresponding to the shoulder surfaces 2a-3 and 2a-3'.

In this case, the transition part 2a-4 is not provided in particular, and the central part 2a-4 is not provided.
The outer surface at both ends of a-2, that is, both shoulder surfaces 2a-
3, 2a - 3' contact the seating surfaces 1 b, 1 b',
It may be supported.

Underdrain 1 at both sides 2a-1, 2a-1' of flexible member 2
．． A protrusion 2c is provided at a portion in contact with the end surface of 1'.

2c' is formed, and a projection 2 is formed on the end surface of the underdrain 1.
At the position corresponding to c, the protrusion 2c is placed during concrete pouring.
A concave groove 1c is formed to receive the .

The protruding portion 2c is tightly received in the concave groove 1c, and restrains the flexible portion 2a from sliding along the end face of the underdrain 1 in a direction perpendicular to the joint axis direction.

FIG. 2 shows a case where one protrusion 2c is provided on the outer surface of each side 2a-1, 2a-1', but this number does not need to be limited to one; A plurality of them may be provided on each of the outer surfaces.

The mounting portion 2b of the flexible member 2 is fixed to the concrete frame by holding the mounting portion 2b of the flexible member 2 between the anchoring fitting 4 fixed to the anchor bolt 3 and the anchoring fitting 5 as a backing plate, and using tightening means such as nuts. After tightening thoroughly according to step 6, concrete is poured to make it watertight.

Although FIG. 2 shows a case in which the anchoring metal fitting 4 has a hook-shaped cross section, a plate-shaped anchoring metal fitting may also be used.

In the case of a hook-shaped anchoring metal fitting, the flexible member 2 can be protected by bringing the side portion 2a-1 of the flexible member 2 into contact with the metal fitting.

However, the anchor bolt 3 may be replaced with other fixing means such as a separate anchor, bolt, and nut.

Between the underdrains 1 and 1', joint materials 7 and 8 are interposed and filled at the inner and outer peripheral positions of the flexible member 2.

The joint materials 7 and 8 are filled not only in the gap between the inner and outer circumferences of the underdrains 1 and 1', but also in the inside of the concave side of the flexible member flexible portion 2a.

Elastic joint materials are used for the joint materials 7 and 8 so that the flexible member 2 can deform and follow the relative displacement between the underdrains 1 and 1' without difficulty.

Among the elastic joint materials 7 and 8, the central portion 2a-2 of the flexible member 2
It is desirable that the joint materials 7a and 8a located in the vicinity of the joint material are made of a soft elastic joint material, such as sponge rubber, in order to facilitate smooth deformation of the central portion 2a-2, which is particularly susceptible to deformation.

It is still desirable to provide a gap 9 near the central portion 2a-2 on the concave side of the U-shaped visible portion 2a.

In Fig. 2, the flexible member 2 was explained with its U-shaped cross section opened outward, but as shown in Fig. 3, it is installed with its U-shaped cross section opened inward. Good too.

The embodiment shown in FIG. 3 is suitable when the internal pressure of the underdrain is high.

Since the configuration is similar to the embodiment shown in FIG. 2, corresponding members are given the same reference numerals as in FIG. 2, and their explanation will be omitted.

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 culverts 1 and 1', and the joint materials 7 and 8 are interposed at the inner and outer circumferential positions, so the flexible member 2 is directly inserted into the culvert. The flexible member 2 is not exposed to external earth and sand or boulders in running water inside, and is not damaged.

When external water pressure, such as groundwater, acts on the joint of the culvert, the external water enters the concave side of the flexible part 2a through the elastic joint material 8, and receives pressure from inside the flexible part 2a, which has a U-shaped cross section. The flexible member 2 tends to deform in a direction that bulges outward.

Therefore, the side outer surface of the flexible portion 2a is in close contact with the end surface of the underdrains 1, 1', and the protrusion 2c provided on the side outer surface,
20' is received in the concave grooves ic, 1c' on the end faces of the underdrains 1, 1', and is automatically maintained in a tightly received state, and the substantially supported suspension of each side part 2a-1, 2a-1' is The length 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 and unreasonable strain from occurring in the flexible member 2.

Also, the shoulder surfaces 2a-3゜2a-3' of the flexible member 2 are connected to the underdrain 1.
, 1', the load applied to the flexible member 2 is also supported by the seat surfaces 1b, 1b', and its pressure resistance performance is dramatically improved.

Furthermore, the distance l between the outer surfaces of both sides of the flexible member 2 is equal to that of the underdrain 1.
, 1' at the inner and outer peripheral positions D1. D2 is shaped more like a dog, so that the flexible member 2 is prevented from escaping from the recesses or stepped portions 1a, Ia' of the underdrains 1, 1', thereby preventing harmful distortion from occurring in the flexible member 2. be done.

On the other hand, if the internal water pressure is greater than the external water pressure, pressure is applied from the convex side of the flexible member 2a and the flexible member 2 tends to deform outward in the direction perpendicular to the joint axis; As mentioned above, the flexible member 2 is built in between the end faces of the underdrains 1 and 1', and is connected to the protrusions 'lc, 'lc' and the concave groove 1.
The engagement with c and 1 c' supports the internal pressure load and prevents harmful deformation and strain from occurring.

Projection 2c, 'lc' and concave groove 1c. Since the elastic joint material 8 is inserted into the concave side of the flexible member 2, the engagement with the flexible member 2 will not easily come off.

Further, when the central portion 2a-2 of the flexible member 2 transitions to the side portion 2a-1 via the tapered or curved transition portion 2a-4, the length of the central portion 2a-2 is short. central part 2
The bending moment applied to a-2 becomes small, and a large pressure can be supported without causing warping deformation.

The watertightness of the joint is determined by the attachment parts 2b, 2 of the short cylindrical flexible member 2.
b' is embedded and fixed in the concrete of the underdrains 1 and 1', so it is completely secured, but the protrusion 2c of the flexible member 2
) 2c' and concave grooves l c , i on the end faces of culverts 1 and 1'
c' and the outer surface of the flexible member 2 and the underdrain 1
, 1' end surface, and the shoulder surface 2a of the flexible member 2.
-3, 2a-3' and seat surface 1b.

It is also maintained by crimp contact with 1 b'.

Next, a case will be described in which a relative displacement occurs between the culverts 1 and 1' in a direction perpendicular to the joint axis direction due to uneven subsidence of the ground or the like.

In this case, joint materials 7a and 8a made of soft sponge rubber are provided at the inner and outer peripheral positions of the central portion 2a-2 of the flexible member 2, and a gap 9 is provided on the concave side. Since the thickness of the flexible member 2 is substantially uniform, the flexible member 2 deforms easily and follows the relative displacement, and the flexible member 2 is free from unreasonable strain or harmful local stress. There is no decrease in durability.

In addition, when the relative displacement has not progressed much, the left and right protrusions 2c and 2c' of the flexible member 2 are still engaged with the concave grooves 1c and 1c' of the culvert 1.1', so that the This provides high pressure resistance and prevents excessive deformation.
The generation of harmful distortion is also suppressed.

Next, each embodiment will be described in the case where the relative displacement between the underdrains 1 and 1' in the direction perpendicular to the joint axis progresses to reach a limit state.

FIG. 4 shows the ultimate state of displacement. In this state, one of the left and right protrusions 'lc, 2c' of the flexible member 2, for example 2c', is located at the end surface of the culvert 1'. However, since the other protrusion 2c remains engaged with the concave groove 1c on the end face of the underdrain 1, excessive deformation of the flexible portion 2a is still prevented.

In addition, even in this state, the flexible member 2 is connected to the underdrains 1 and 1'.
Since most of the flexible member 2 is located between the end faces and is hardly exposed to earth and sand or counterflowing water from the underdrain, the flexible member 2 is sufficiently protected.

Figure 5 shows a case where uneven settlement occurs in the opposite direction to Figure 4 between the underdrains 1 and 1' (C) which should be connected at the joint of the culvert in Figure 2, but it is similar to Figure 4. Detailed explanation will be omitted since the same effect will be obtained.

When using the culvert joint according to the present invention, a flexible member having a flexible portion having a U-shaped cross section is built into the center of the culvert frame between the end faces of a pair of culverts to be connected, and joint material is placed at the inner and outer peripheral positions of the flexible member. Since it is interposed, it is possible to absorb large relative displacements, and it is also possible to prevent the flexible member from being damaged by earth and sand inside and outside the culvert, and by boulders in flowing water.

The built-in flexible member between the end faces of the underdrain can be maintained even when a relative displacement occurs between the underdrains.

However, since the spacing between the outer surfaces of both sides of the flexible member is greater than or equal to the spacing between the culverts at the inner and outer peripheral positions of the culvert, that is, equal to or greater than the spacing between the culverts, the flexible member The member is prevented from being excessively deformed by escaping from the recess or stepped portion of the end face of the underdrain under pressure, and generation of harmful strain is prevented.

In addition, since the shoulder surface of the flexible member is supported by the seat surface of the underdrain, if pressure is applied from the U-shaped concave side of the flexible joint,
Since this load is supported by the seat surface, the pressure resistance of the flexible member can be dramatically improved.

In addition, 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 closely received in the concave grooves formed on the end surface of the culvert, so that the flexible section It is supported so as not to slide on the end face, which not only further improves the pressure resistance performance but also shortens the effective suspension length of the flexible member.
When external pressure such as underground water pressure or internal pressure such as internal water pressure acts, the pressure itself acting inside the U-shaped cross-sectional flexible part is effectively utilized to strengthen the suspension of the flexible member to the end face of the culvert,
The occurrence of harmful distortion can be further suppressed.

The engagement between the protrusion and the concave groove is also maintained by the joint filler inserted inside the U-shaped flexible section, making it possible to maintain a stable engagement state and ensure stable pressure resistance. It is possible to suppress the occurrence of harmful distortion.

In this case, if a joint material made of sponge rubber, which is softer than the joint material in other parts, is used for the joint material near the center of the flexible member, it is possible to reduce the flexibility caused by the relative displacement between the culverts. The follow-up deformation of the member becomes smooth, unreasonable concentration of stress can be avoided, and the effect of suppressing the occurrence of harmful strain can be further promoted.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a culvert equipped with the culvert joint of the present invention;
FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and is a cross-sectional view before relative displacement occurs between the underdrains, according to an embodiment of the underdrain joint of the present invention. FIG. 4 is a cross-sectional view of a joint of a culvert according to another embodiment in which the U-shaped cross section of the flexible member is opened inward and installed, and a relative displacement occurs between the culverts of the joint of the culvert of FIG. 2. FIG. 5 is a cross-sectional view of the underdrain joint of FIG. 2 after a relative displacement occurs between the underdrains in the opposite direction to that shown in FIG. 4. 1.1'...Drainage, 1a, 1a'...Recessed portion or step, 1b, 1b'...Seat surface, 1c,
1c'-concave groove, 2... flexible member, 2a... flexible part, 2a-1, 2a-1'... side part, 2a-2...
・Central part, 2a-3, 2a-3'00. Shoulder surface, 2
b, 2 b'--mounting part, 2 c, 2 c
'-Protrusion, 4.5... Anchoring fitting, 6... Fastening means, 7, 8... Joint material, 7a, 8a... Soft joint material, such as sponge rubber, 9... Gap .

Claims (1)

[Scope of Claims] 1. A recess or step is provided near the center of the culvert body on each of the opposing end faces of a pair of culverts to be connected to form a seating surface, and between the end faces of the central part of the culvert, The culvert is formed into a U-shaped cross section with both side parts and a central part, and the distance between the outer surfaces of the side parts is larger than the distance between the underdrains at the outer periphery position on the convex side of the U-shaped flexible part, and has a uniform thickness. A flexible member made of an elastic material such as rubber or synthetic resin is installed in the culvert, and includes a flexible member having a flexible part having Both shoulder surfaces of the central portion of the flexible member are supported on the seat surface formed in the recess or step! A joint for a culvert, which is characterized by being made to hold. 2. The underdrain joint according to claim 1, wherein the shoulder surface is formed on the outer surface of the transition portion from the center to the side portion of the U-shaped flexible portion. 3. According to claim 1 or 2. In the underdrain joint, a protrusion is formed on the outer surface of each side of the flexible portion having a U-shaped cross section of the flexible member, and the protrusion is closely received in a concave groove formed on the end surface of the underdrain. Something that exists. 4 Each of the opposing end faces of a pair of culverts to be connected. A recess or step is provided near the central position of the culvert body to form a seating surface, and between the end faces of the central parts of the culvert bodies, a U-shaped cross section is formed between both sides and the central part, and between the outer surfaces of the sides. a flexible portion having a substantially uniform thickness, the spacing being equal to the distance between the culverts at the outer periphery position on the convex side of the U-shaped flexible portion;
A flexible member made of an elastic material such as rubber or synthetic resin is installed in the culvert, and has attachment parts extending toward the back of the culvert at both ends of the flexible part, and both shoulders of the central part of the flexible member are installed in the culvert. The surface is supported by a seating surface formed in the recess or step, an elastic joint material is interposed between the culverts at the inner and outer peripheral positions of the flexible member, and a soft joint material is provided near the center of the flexible member. An underdrain joint characterized by intervening an elastic joint material. 5. The underdrain joint according to claim 4, wherein the shoulder surface is formed on the outer surface of the transition part from the center to the side part of the U-shaped flexible part. 6. In the underdrain joint according to claim 4 or 5, a protrusion is formed on the outer surface of each side of the flexible section having a U-shaped cross section of the flexible member, and the protrusion is A concave groove formed on the end face of a culvert that is tightly inserted into the concave groove.