JP4835905B2 - Flexible box culvert - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a precast concrete box culvert installed in the ground for flowing rainwater, sewage, etc., and in particular, a flexible box having a joint mechanism for connecting adjacent box culvert units to each other. It is about culvert.

  A flexible box culvert that constructs a long drainage channel in the ground is generally connected to the end surfaces of a large number of box culvert units in a watertight manner through flexible members, and the box culvert is maintained to maintain this state. The unit bodies are connected to each other by a joint mechanism.

  By the way, when the earthquake or foundation ground is soft, the surrounding foundation may be deformed. In preparation for such a case, in the flexible box culvert, the other box culvert unit is adjacent to the other. The box culvert unit can be displaced.

  In this type of flexible box culvert joint mechanism, a male screw rod is loosely inserted into a through hole extending from a recess to an end formed in the peripheral surface of one box culvert unit body, and the one box The protruding portion of the male threaded rod is loosely inserted into an insertion hole extending from the end of the other box culvert unit body into the recess of the other box culvert unit body 1. A nut is screwed into the male threaded rod portion projecting toward the concave portion of one box culvert unit body 1 and an elastic body is inserted into the male threaded rod portion projecting toward the concave portion side of the other box culvert unit body. A nut is screwed in (for example, Patent Document 1).

However, in the above-mentioned flexible box culvert, flexibility can be secured by using an elastic body, but the other box culvert unit body is displaced with respect to one box culvert unit body by a slight external force or its own weight. As a result, there arises a situation in which sufficient sealing performance cannot be ensured and falls below the originally planned flow capacity.
Patent 2688344 (see FIG. 7)

  Therefore, in the present invention, a flexible box culvert in which the other is not displaced with respect to one of adjacent box culvert units due to an external force or its own weight applied during construction, and the displacement occurs correspondingly when the peripheral base is deformed. The issue is to provide.

(Invention of Claim 1)
In the present invention, a joint mechanism is provided to connect adjacent box culvert units to each other, and when the ground is deformed, one of the adjacent box culvert units can be displaced with respect to the other. In the flexible box culvert, the joint mechanism is configured such that the shaft body that protrudes from the end portion of one box culvert unit body in a state of being prevented from coming off is the peripheral surface of the other box culvert unit body from the end portion of the other box culvert unit body. An enlarged diameter portion that is loosely inserted into an insertion hole that extends into the recess formed in the shaft and that is integrated or screwed into a portion that reaches the recess in the shaft body, and is inserted through the constituent wall surface of the recess. Between the wall surface provided with the hole and the enlarged diameter portion, a molded body made of steel, stainless steel, or hard resin having a crushed space is interposed, and the hole formed in the molded body Body was inserted, molded body is not buckling by the small load and self-weight according to the time of construction, a certain force or greater by soil deformation after construction acts are as buckle, and, adjacent box culvert unit body They are sealed with a flexible member, and the sealing performance is maintained by the expansion and contraction of the flexible member even when there is a gap between adjacent box culvert units.
(Invention of Claim 2)
The flexible box culvert of the present invention relates to the invention of claim 1 above, and has an insertion hole extending from a concave portion to an end portion provided on the peripheral surface of one box culvert unit body, and the shaft body is provided in the insertion hole. It is loosely inserted in the retaining state.
(Invention of Claim 3)
The flexible box culvert of the present invention relates to the invention according to claim 1 or 2, wherein a hard resin or metal plate is provided between the constituent wall surface of the recess and the enlarged diameter portion.
(Invention of Claim 4)
The flexible box culvert of the present invention relates to the invention according to any one of claims 1 to 3, and the shaft body is a male threaded rod.
(Invention of Claim 5)
The flexible box culvert of the present invention relates to the invention according to any one of claims 1 to 4, wherein the flexible member comprises a main component mainly composed of a hydroxyl-terminated liquid polybutadiene and a liquid prepolymer as a major component. It is assumed that it is made by mixing and reacting the hardener .

  According to the flexible box culvert of the present invention, the other of the adjacent box culvert units is not displaced depending on the external force or its own weight applied during construction, and the displacement occurs correspondingly when the peripheral base is deformed. It will be a thing.

  Hereinafter, an embodiment as the best mode for carrying out the flexible box culvert BK of the present invention will be described in detail.

FIG. 1 is a side view of a flexible box culvert BK according to an embodiment of the present invention, and FIG. 2 is a joint mechanism 2 for preventing the box culvert unit bodies 1 and 1 constituting the flexible box culvert BK from separating from each other. 3 is a side view of the joint mechanism 2, FIG. 4 is an exploded perspective view of the joint mechanism 2, and FIG. 5 is a view of the joint mechanism 2 showing a state before the U-shaped molded body 24 is buckled. 6 is an explanatory diagram of the joint mechanism 2 showing a state after the molded body 24 having a U-shaped cross section is buckled, and FIG. 7 is a flexible member between the adjacent box culvert unit bodies 1 and 1. FIG. 8 is a front view of the box culvert unit body 1.
(About this flexible box culvert BK)
As shown in FIGS. 1 to 8, the flexible box culvert BK is provided with a joint mechanism 2 to prevent the adjacent box culvert unit bodies 1 and 1 from being separated from each other. When the flexible member 3 is interposed between the opposing portions of the two and the ground is deformed, the other of the adjacent box culvert units 1 and 1 is deformed by the deformation of the flexible member 3. Slight displacement is possible.

Hereinafter, the box culvert unit body 1, the joint mechanism 2, the flexible member 3, and the like, which are the main components for forming the flexible box culvert BK, will be described in detail.
(About box culvert unit field 1)
As shown in FIG. 8, the box culvert unit body 1 is made of concrete formed in a cylindrical body whose outer shape is a front view. For example, the outer dimension is 1260 mm × 1260 mm, the inner dimension is 1000 mm × 1000 mm, the meat Thickness: 130 mm and length: 2000 mm. In the box culvert unit 1, as shown in FIGS. 1 and 7, a male portion 11 is formed on one end face, and a female portion 12 is formed on the other end face. In a state where the unit bodies 1 and 1 are connected to each other via the joint mechanism 2, the male part 11 is fitted into the female part 12.

  Here, the box culvert unit body 1 has an inner dimension of 1000 mm × 1000 mm as described above. However, as shown in FIG. , 10, 10 are configured. And the recessed part 14 for installing the coupling mechanism 2 is provided in the position of the thick part 10 a little away from the end surface of the box culvert unit 1 as shown in FIGS. An insertion hole 15 is provided in the end face of the culvert unit body 1.

Further, as shown in FIG. 7, the end faces of the male part 11 and the female part 12 in the connecting portions of the box culvert units 1 and 1 are each about 20 mm from the inner peripheral face toward the outer peripheral face and 10 mm from the end face. Recessed portions 16a and 16b formed to a certain size are provided. In addition, although this hollow part 16a, 16b is for filling the flexible member 3 explained in full detail below, depending on the case, either the hollow part 16a or the hollow part 16b may be sufficient, The size is not limited to the above.
(About joint mechanism 2)
As shown in FIGS. 2 to 4, the joint mechanism 2 has a U-shaped cross section including a nut 20, a plate 21, a male screw rod 22, and a back plate portion 24 a and two tooth portions 24 b on the plate 23. The molded body 24 (corresponding to the molded body made of a steel material having a crushing space described in the column of means for solving the problem), the deformable member 2A formed by integrally fixing the plate 25 in order, and the nut 26 The plate 21 has a bolt insertion hole 21h, the plate 23 has a bolt insertion hole 23h, the molded body 24 has a bolt insertion hole 24h, and the plate 25 has a bolt insertion hole 25h. It is as. In addition, all the members which comprise this coupling mechanism 2 use what was manufactured with the steel material or the material which has the rigidity similar to this.

  As shown in FIGS. 2, 3, and 5, in the joint mechanism 2, a male screw rod 22 (shaft body) is loosely inserted into the insertion hole 15 extending from the concave portion 14 to the end portion of one box culvert unit body 1. And the protruding portion of the male screw rod 22 extends from the end of the other box culvert unit 1 to the other box culvert unit 1. 1 is inserted into the insertion hole 15 extending into the recess 14. A nut 20 (enlarged diameter portion) is screwed into the male screw rod 22 portion protruding to the concave portion 14 side of one box culvert 1 and the male screw rod protruding to the concave portion 14 side of the other box culvert unit body 1. A nut 26 (enlarged diameter portion) is screwed into the 22 portion via the deformable member 2A. A plate 21 is interposed between the wall surface of the recess 14 and the nut 20.

  Here, when a small force that opens the box culvert unit bodies 1 and 1 connected by the joint mechanism 2 is applied, the molded body 24 having a U-shaped cross section is buckled (back plate portion 24a and The male threaded rod 22 extends only slightly (within an elastic range or a proportional range) without causing the space formed by the teeth 24b of the sheet to collapse, but the box culvert units 1, 1 are increased as the force increases. When a force is applied to open each other more than a certain amount, the two teeth 24b of the molded body 24 buckle from the state shown in FIG. 5 to the state shown in FIG. 6, and as a result, the adjacent box culvert unit 1 , 1 can be displaced about 15 to 30 mm, for example.

  That is, according to this joint mechanism 2, the flexible box culvert BK is not deformed with respect to a small load at the time of construction or the own weight of the box culvert unit body 1, and corresponds to the level 1 and 2 earthquake motion. It will have deformation performance. Level 1 seismic motion refers to seismic motion that has a high probability of occurring during the sharing period of the flexible box culvert BK, and Level 2 seismic motion refers to seismic motion with a large intensity that has a low probability of occurring in the flexible box culvert BK. Say.

"Other forms of joint mechanism 2"
The joint mechanism 2 of this embodiment is the same as that of the above-described embodiment, “a male screw rod 22 (shaft body) is loosely inserted into the insertion hole 15 extending from the recess 14 to the end of one box culvert unit body 1. , The socket S is embedded in the end portion of one box culvert unit body 1 as shown in FIG. The male screw rod 22 protrudes from the end portion of the one box culvert unit body 1 so that the male screw rod 22 is screwed into the first box culvert unit body 1 ”. When this mode is adopted, the male threaded rod 22 and the nut 26 can be changed to a headed bolt.

“Modified Example of Molded Body 24”
The molded body 24 used in the joint mechanism 2 has a U-shaped cross section. However, the cross-sectional shape is not limited to this, and a trapezoidal shape, a square shape, a rectangular shape, a circle shape, an ellipse shape, or other polygonal shapes can be used. In short, it suffices if there is a collapsed space in which a part of the molded body 24 undergoes plastic deformation such as buckling when a force of a certain level or more is applied, and can be flattened in the direction in which the force acts.

  Further, if the thickness corresponding to the back plate portion 24a is increased, the plate 25 is unnecessary.

Further, the molded body 24 is not limited to a steel material having a crushing space, but may be a stainless steel material or a hard resin having a crushing space, or a FRP material.
(About the flexible member 3)
The flexible member 3 is a cured product obtained by mixing and reacting a main component mainly composed of a hydroxyl group-terminated liquid polybutadiene and a curing agent mainly composed of a liquid prepolymer. It has a stable three-dimensional network structure (Sotomo Co., Ltd .: trade name “TS Sticker”).

  The basic blending ratio is the weight ratio of polybutadiene-based urethane rubber (main component for making a rubber-like product): plasticizer (oil extender that imparts rubber flexibility): filler ( Hardness adjustment for maintaining the shape during molding of the material): anti-aging agent (preventing rubber deterioration) = (25-35): (30-40): (40-50): (2-5) preferable.

"Chemical structure of flexible member 3"
The chemical structure of the flexible member 3 is three-dimensional by combining with other linear structures at a ratio of 5 to 10 molecules as shown in FIG. 10 with respect to the linear structure shown in FIG. A mesh structure is formed.

"Elongation rate test of this flexible member 3 and adhesion strength with concrete"
A sample piece (upper and lower surface dimensions: 30 mm × 70 mm, height dimension: 30 mm) is made of the same material as the flexible member 3, and a concrete piece is attached to the upper and lower surfaces of the sample piece. The adhesion strength between the concrete piece and the sample piece and the elongation rate of the sample piece were measured by pulling the concrete piece on the lower surface side in the opposite direction.
.

  As a result, the sample piece and the concrete piece were detached at the bonding surface when the tensile force was 740 N (the flexible member 3 was not broken). The total length of the flexible member 3 at that time was 196 mm.

From these results,
Adhesive strength = 740 N / (300 mm × 70 mm) = 0.35 N / mm ²
Elongation rate = (193-30) mm / 30 mm × 100 = 553%
It turns out that it is.

  That is, it can be seen that the flexible member 3 has a high adhesion strength and a high elongation rate.

In addition, as mentioned above, the basic compounding ratio of the flexible member 3 is a polybutadiene-based urethane rubber (main component for making a rubber-like product) as a main component by weight ratio: plasticizer (rubber flexibility, etc. Oil extender): Filler (hardness adjustment to maintain the shape during molding of the material): anti-aging agent (preventing rubber deterioration) = (25-35): (30-40): (40-50) : (2-5), it is considered that the adhesion strength is 0.3 to 0.4 N / mm ² and the elongation is 200 to 500% (preferably 300 to 500%).

"Other excellent points in this flexible member 3"
As described above, this flexible member 3 has functions of high adhesion strength and high elongation, and also has excellent elasticity against long and short time stresses, and water resistance and water tightness. And has a function of curing in water.

“Installation Mode of the Flexible Member 3 Between the Box Culvert Units 1 and 1 and Others” When the box culvert unit bodies 1 and 1 are connected to each other, as shown in FIG. The flexible member 3 is filled in the circumferential groove portion constituted by 16b.

In addition, a backup material 4 made of hard resin (for example, mechanical plastic) or metal is provided on the outer peripheral side of the depressions 16a and 16b so as to fill a gap formed between the depressions 16a and 16b, and the backup material A spacer 5 made of hard resin (for example, mechanical plastic) or metal is provided between the opposing surfaces of the box culvert unit bodies 1, 1 which are on the outer peripheral side than 4.
(About the excellent functions of this flexible box culvert BK)
(1) Deformability and waterstop The flexible box culvert BK has deformation performance as described above, but the molded body 24 does not buckle at the time of construction or for a small load. Since the threaded rod 22 extends to a slight extent (elongation in the elastic range or proportional range), almost no deformation occurs as shown in FIG. Therefore, the water stop function by the flexible member 3 is perfect, and the situation where it falls below the originally planned flow capacity does not occur.

On the other hand, in this flexible box culvert BK, when the ground deformation occurs due to level 1 or 2 ground motion, the molded body 24 buckles as shown in FIG. 6, and the box culvert unit body as shown in FIG. The deformation occurs in such a manner that a gap g is generated between the first and the first. By the way, as described above, the flexible member 3 for stopping water is large with an adhesion strength of 0.35 N / mm ² and an elongation of 553%, so that the box culvert units 1 and 1 are mutually connected as shown in FIG. Even when the gap g is generated between them, there is little risk of cutting or peeling from the end face of the box culvert unit body 1, and the water stop state is maintained (improved).

That is, the flexible box culvert BK is not deformed as much as possible so that the gap g is not formed with respect to a small external force, and is deformed greatly only when the external force exceeds a certain level. . And in both states mentioned above, water-stopping is ensured.
(2) Low cost and workability After the box culvert unit 1 and 1 are installed with the joint mechanism 2, basically, the main component mainly composed of hydroxyl-terminated liquid polybutadiene and the liquid prepolymer as the main component. The flexible member 3 formed by mixing and reacting the hardener is simply filled into the hollow portions 16a and 16b (which may be either one) having a simple shape with a filling gun or the like. It is considered that the cost is low considering the water stop effect.
(Other)
The cross-sectional shape, dimensions, and length of the box culvert unit 1 described above are not limited to the above-described embodiments, and can be freely changed.

The side view of the flexible box culvert of the Example of this invention. The top view of the coupling mechanism 2 for preventing the box culvert unit bodies constituting the flexible box culvert from being separated from each other. The side view of the said joint mechanism. The disassembled perspective view of the said joint mechanism. Explanatory drawing of the joint mechanism which shows the state before buckling of steel materials with a U-shaped cross section. Explanatory drawing of the joint mechanism which shows the state after the U-shaped steel material buckled. Sectional drawing which shows the state which provided the flexible member between the said box culvert unit bodies adjacent. The front view of the said box culvert unit body. The linear structure figure which shows the chemical structure of a flexible member. The chemical structure of the said flexible member is a figure which shows the state which has couple | bonded with another linear structure in the ratio of the molecule | numerator once to 5-10 pieces, and has comprised the three-dimensional network structure. The figure which shows the structure at the time of construction of the said flexible box culvert. The side view which shows the state which deform | transformed in the aspect which a clearance gap produces between box culvert unit bodies. Explanatory drawing of the coupling mechanism of other embodiment.

Explanation of symbols

g Gap BK Flexible box culvert 1 Box culvert unit body 2 Joint mechanism 2A Buffer member 3 Flexible member 4 Backup material 5 Spacer 10 Thick part 11 Male part 12 Female part 13 Concave part 14 Insertion hole 15 Depressed part 20 Nut 21 Plate 21h Bolt insertion hole 22 Male screw rod 23 Plate 23h Bolt insertion hole 24 Molded body 24h Bolt insertion hole 25 Plate 25h Bolt insertion hole 26 Nut

Claims (5)

A flexible box culvert provided with a joint mechanism for connecting adjacent box culvert units to each other so that when the ground is deformed, one of the adjacent box culvert units can be displaced with respect to the other. In the coupling mechanism, the shaft body that protrudes from the end portion of one box culvert unit body in a retaining state is formed on the peripheral surface of the other box culvert unit body from the end portion of the other box culvert unit body. It is loosely inserted into an insertion hole that reaches into the recess, and has an enlarged diameter portion that is integrated or screwed into a portion of the shaft that reaches the recess, and an insertion hole is provided in the constituent wall surface of the recess. A molded body made of steel, stainless steel or hard resin having a crushing space is interposed between the wall surface and the enlarged diameter portion, and the shaft body is inserted into a hole provided in the molded body. , Moldings, not buckling by the small load and self-weight according to the time of construction, a certain force or greater by soil deformation after construction acts are as buckle, and, in between adjacent box culvert unit body mutually soluble A flexible box culvert which is sealed by a flexible member and maintains sealing performance by expansion and contraction of the flexible member even when a gap is formed between adjacent box culvert units .   The insertion hole from the recessed part provided in the surrounding surface of one box culvert unit body to an edge part is provided, and the said shaft body is loosely inserted in the said insertion hole in the retaining state. Flexible box culvert.   3. The flexible box culvert according to claim 1, wherein a plate made of hard resin or metal is provided between the constituent wall surface of the concave portion and the enlarged diameter portion.   The flexible box culvert according to claim 1, wherein the shaft body is a male screw rod. 5. The flexible member according to any one of claims 1 to 4, wherein the flexible member is obtained by mixing and reacting a main component mainly composed of a hydroxyl-terminated liquid polybutadiene and a curing material mainly composed of a liquid prepolymer. Flexible box culvert.

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