JPH09324457A - Box culvert as measures against uneven settlement or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a box culvert using a flexible jointing material, capable of eliminating a split into two halves, and consequently improving moldability, a mold releasing function and portability. SOLUTION: A box culvert 1 is made of precast concrete formed like a cylinder for building an underground structure such as a covered conduit and an underground road. In addition, a flexible jointing material 4 of the prescribed breadth is buried within the annular cross section of the cylinder in parallel with both or one of the inner and outer surfaces thereof. A breakage forming part 3 is annularly provided within the cylindrical cross section of the cylinder approximately along the center line of the jointing material 4. As a result, stress is concentrated on a gap between the breakage forming part 3 and the inner or outer surface of the cylinder, upon the occurrence of uneven settlement or the like. thereby allowing a breakage.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a case where an underdrain or an underpass is constructed by a box culvert produced in a factory,
The present invention relates to a box culvert for the purpose of preventing uneven settlement, which prevents disconnection, damage, or deterioration of water shutoff of the connecting part due to uneven settlement of the ground.

[0002]

2. Description of the Related Art It is well known in the art that an underdrain or an underpass constructed by a box culvert may cause a disconnection, a breakage, or a decrease in water shutoff due to uneven settlement of the ground.

Therefore, a strain absorbing box culvert is provided as a measure against the differential settlement of the box culvert (see Japanese Utility Model Publication No. 3-23701). This strain absorbing box culvert is made by connecting two divided bodies cut along the width direction with a flexible connecting member, and the flexible connecting member is composed of a hollow annular body and an annular anchor piece protruding from both sides of the hollow annular body. The anchor piece is formed by embedding it in the end faces of the opposed two-divided body.

[0004]

However, according to the above-described strain absorbing box culvert, in the forming method thereof, the flexible connecting material is embedded between the opposed end faces of the box culvert divided into two parts. Therefore, first, after molding one of the two divided bodies in the molding die, after the concrete is solidified (hardened) to the extent that it does not deform,
A work step of placing a mold for the other divided body and driving concrete into the mold is required (Japanese Patent Application No. 63-316).
944). Therefore, there are at least 2 work steps.
However, there is a drawback that the production efficiency is low.

Further, in the demolding step, since the two divided members are connected by the flexible connecting member which is weak in strength, the flexible connecting member is not compressed and broken by the upper divided member after the molding die is removed. As described above, it is necessary to perform mold release in a state where the upper and lower divided bodies are held apart from each other by some reinforcement or support means, and are stored as they are, or when the reinforcement or support member is removed. Must be stored with the two pieces lying on the ground.

[0006] Further, also during transportation, in order to prevent the breakage and damage of the flexible connecting member, a supporting member for keeping a constant distance between the divided bodies is required. The supporting member may be, for example, a steel material that connects the divided bodies, but in any case, this steel material must be connected to the divided bodies. In order to connect the steel material to the split body, anchor bolts and the like must be driven into the split body, and because special attention is required to drive the anchor bolt into the box culvert, an accompanying complicated process is required. It goes without saying that

Therefore, the present invention is a box culvert using a flexible connecting member to prevent uneven settlement, and is not divided into two parts, thus improving moldability, releasability and transportability. Provide what you let them do.

[0008]

According to a first aspect of the present invention, there is provided a box culvert for preventing differential settlement or the like.
A box culvert made of cylindrical precast concrete for constructing underground structures such as underdrains and underpasses, in which a flexible connecting material of a predetermined width is embedded in the annular cross section parallel to the inner and outer surfaces. In addition, the fracture forming portion is formed in an annular shape in the tubular cross section along the substantially center line of the flexible connecting member, and when the sinking is uneven, stress is generated between the fracture forming portion and the inner and outer surfaces. It is characterized by being formed so that it can be broken in a concentrated manner. With such a structure, it can be molded as an integrated product in which the flexible connecting material is embedded, and it is excellent in moldability, and further, storage and transportability are improved.

According to the second aspect of the present invention, the flexible connecting member has a cylindrical portion, a plate-shaped portion that extends laterally around the cylindrical portion and extends forward or backward, or either forward or backward, and a tubular inner or outer portion. It is characterized in that it comprises an anchor portion projectingly provided so as to intersect with a plate-like portion having a predetermined width and extending to the left and right parallel to the surface.
With such a structure, stress is concentrated between the plate-shaped portion projecting forward and backward and the inner and outer surfaces, so that it is easy to fracture in the case of differential settlement.

According to a third aspect of the present invention, the flexible connecting member is characterized in that the cylindrical portion has an expanding / contracting portion formed in a hollow substantially triangular shape or a half-moon shape. With such a structure, when the concrete is broken with the flexible connecting member sandwiched therebetween, the flexible connecting member is stretched and the breaking of the flexible connecting member at the time of differential settlement is prevented.

According to a fourth aspect of the present invention, concave portions facing each other with the flexible connecting member interposed therebetween and through holes communicating between the concave portions are formed in the concrete cross section, and the PC steel rod is provided in the through holes. It is characterized in that it has a breakage control portion formed by inserting an elastic body into the concave portion at both ends or one end thereof in a compressible manner. With such a structure, it is possible to prevent the flexible connecting material from breaking along with the breaking of concrete.

According to a fifth aspect of the present invention, the PC steel rod penetrates through the expansion / contraction member interposed between the end faces between the box culverts. With this structure, the expansion and contraction member responds to expansion and contraction between the box culverts, and
It is possible to prevent a decrease in water blocking property.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. As shown in Figs. 1 and 2, the box culvert 1 for countermeasures against uneven settlement, etc. is a precast concrete that is formed into a tubular shape of a predetermined size by concrete according to the ordinary method of box culvert manufacturing, and has a cross section at a substantially central portion in the width direction. A flexible connecting member 4 having a predetermined width is embedded in the member 2 and integrally molded. Therefore, the box culvert 1 is an integrated product without being divided into two bodies. As shown in FIG. 2, corner build-up portions 6 are formed at the four inner corners, and the respective corner build-up portions 6 are formed.
A through hole 7 is provided in the longitudinal direction, and a PC is inserted in this through hole 7.
A steel rod can be inserted.

The flexible connecting member 4 is an annular body in which a plate-shaped portion 4b is formed integrally with the cylindrical portion 4a at the left and right by a predetermined width, and a cylindrical portion 4c is integrally formed at the end of the plate-shaped portion 4b. The plate-like portion 4b is integrally formed with the columnar portion 4c and a plurality of prismatic portions 4d serving as anchors. Then, the fracture forming portion 3 including the plate-shaped portions 4b and 4b and the cross-shaped plate-shaped portions 4e and 4e is provided in the cylindrical portion 4a with a predetermined length.
It is integrally formed in an annular shape along a, and a predetermined distance W ₁ is held between the end of the plate-like portion 4e and the cut grooves 2 and 3.

The material of the flexible connecting member 4 is rubber or highly flexible synthetic resin. Rubber includes not only natural rubber but also synthetic rubber such as butyl rubber. If necessary, any material having good moldability and flexibility and durability may be used. The distance W ₁ is preferably 20 mm or more. Plate part 4
Although e is a series of annular shapes, it may be divided, and the wall thickness may be larger than that of the plate-like portion 4b, or may be provided only on either the inside or outside of the tubular shape. The breakage forming portion 3 may be formed only on one of the inner and outer sides.

The shape of the flexible connecting member 4 is merely an example, and the cylindrical portion 4a may have an oval shape or a polygonal shape in addition to a circular cross section, and is not limited to a hollow shape. It may be solid depending on the degree of the flexible material. Further, the prismatic portion 4d is not limited to this, and may have an arrowhead shape, a triangle shape, or a plate shape, and may have any shape as long as it is a shape effective as an anchor if necessary. Incidentally, regarding the shape of the flexible connecting member 4, as shown in FIG. 6 (A), one having an expandable portion formed by arranging two hollow triangles 4f in parallel instead of the cylindrical portion 4a, or FIG. ), It may have an expandable portion having a slightly large diameter hollow semicircular shape 4g.

Further, butyl rubber may be arranged between the prismatic portions 4d or between the cylindrical portion 4c and the prismatic portion 4d in order to improve the water blocking property of the flexible connecting member. Butyl rubber fills the gap between the cross section 2 and the flexible connecting member 4 to completely stop the water. Therefore, as shown in FIG. 4, the fracture forming portion 3 may be formed by forming a hollow portion 4f having a rectangular cross section in which the cylindrical portion 4a and the plate portion 4e of FIG. 2 are united.

Therefore, as shown in FIGS. 3 and 4, although the box culvert 1 for preventing uneven settlement is formed integrally by embedding the flexible connecting member 4 in the cross section 2, FIG.
When a tensile force F is applied to the box culvert 1 as shown in FIG. 5A or a rotational force F ₁ is applied to the box culvert 1 as shown in FIG.
Although stress is concentrated between the inner and outer surfaces of 4e and the concrete ruptures from the inner surface, the cylindrical portion 4a of the flexible connecting member 4 is exposed, but the plate-shaped portion 4b extends and blocks the gap and remains. In the case of the flexible connecting member 4 shown in FIG. 6 (A), as shown in FIG. 6 (B), triangular base parts 4h, 4 are formed.
As h cuts and the hypotenuses become a series, they expand each other,
In addition, as shown in FIG. 6C, the semicircular diameter side portion 4i.
Can be cut and stretched, and the gap between the ruptured concretes can be maintained at a high waterproofness.

Therefore, if the forces F and F ₁ are excessive,
Since the flexible connecting member 4 is broken, the box culvert 1 is used to prevent the flexible connecting member 4 from breaking.
It is desirable to provide a breakage control section on itself. As shown in FIG. 7, the breakage control portion 8 has recesses 9 facing each other with the flexible connecting member 4 sandwiched therebetween, which are formed in the concrete surface by communicating with the through holes 7 and are aligned in the longitudinal direction thereof. The PC steel rod 10 is inserted between the recesses 9 to be formed, and elastic bodies are interposed at both ends or one end thereof.

That is, as shown in FIG. 8, the PC steel rod 1
The screw part 11 is formed at both ends of the washer 0, and the nut 14 is screwed into the screw part 11 with the washers 12 and 13 interposed therebetween.
The nut 14 is fastened with the elastic body 15 interposed between the nuts 2 and 13. The elastic body 15 may be a simple tubular body, but an axial cut 16 is provided to facilitate mounting between the washers 12 and 13.
A cylindrical body having a larger diameter than the washers 12 and 13 provided with is preferable. The elastic bodies 15 may be provided on both sides of the PC steel rod 10, or may be provided on only one side. This elastic body is made of synthetic resin such as rubber or urethane and is compressed in the axial direction.

Next, a description will be given of an application example of the box culvert 1 for countermeasures against the differential settlement, as shown in FIG. 7, in which the normal box culverts 1a and 1a are installed with the box culvert 1 sandwiched therebetween. In this case, it is necessary to connect in the longitudinal direction, and the connection uses the through hole 7 and the recess 9 formed so as to communicate with the box culverts 1 and 1a.
The PC steel rod 10a is inserted into the through hole 7 and the box culverts 1 and 1a are tightened in the recess 9 in the longitudinal direction. Further, an expansion / contraction member 30 is appropriately interposed between the end faces of the box culverts 1 and 1b. A recess 9 communicating with the through hole 7 is formed in the box culvert 1b, and both ends of the PC steel rod 10a penetrating the through hole 7 are fastened in the recesses 9 and 9 with nuts or the like.

That is, as shown in FIG. 10, the box culverts 1 for preventing differential settlement are arranged in contact with the ordinary box culverts 1a, 1b arranged in series, and the PC steel is provided in each of the through holes 7 of the box culverts 1a, 1b. Insert the rod 10a, box culvert 1 and box culvert 1
In the concave portion 9a, the nuts are screwed into the threaded portions at both ends by a normal road, and then tightened. As shown in FIG. 11, the recess 9 is formed in the corner build-up portion 6 in which the through hole 7 is formed, and is open to the passage side inside.

For tightening the PC steel rod 10a, as shown in FIG. 12, the nut 18 is screwed into the threaded portion 19 of the PC steel rod 10a with the washer 17 interposed in the recess 9 of the box culvert 1a. A coupler 20 is screwed onto the threaded portion 19 and a tension bar 21 inserted into the through hole 7 of the box culvert 1 is connected to the coupler 20. The center bar jack 22 is attached to the tension bar 21 at the end of the box culvert 1. With the anchor plate 23 interposed therebetween, the nut 24 is screwed into the threaded portion at the end, and the PC steel rod 10a is tightened by the center hole jack 22 to incorporate a tension force.

When the tightening of the PC steel rod 10a is completed, the tightening tool made of the above-mentioned members is removed, and the PC steel rod 10 is inserted into the through hole 7 between the concave portions 9 of the box culvert 1 as shown in FIG. Then, the washer 12 is interposed between the threaded portions 11 at both ends thereof, and the nut 14 is screwed and manually tightened. In this case, as shown in FIG. 14 and as described above, the nut 14 at the end of the PC steel rod 10 is loosened and the elastic body 1 is interposed between the washers 12 and 13.
5 can be interposed. The washer 13 may be omitted depending on the diameter of the nut 14.

Then, as shown in FIG. 15, the ordinary box culverts 1c, 1d, 1e in the next construction section are further installed in the box culvert 1 and a new PC steel rod 10b is provided in the through hole 7 communicating between them. And the same washer and nut 26 as the washer 17 and nut 18 in the recesses 9 and 9 of the box culverts 1 and 1e at both ends thereof.
After fitting and screwing, the coupler 20 is connected to the PC steel rod 10b in the recess 9 of the box culvert 1e, and one end of the tension bar 21 having the through hole 7 inserted into the coupler 20 is connected. The center hole jack 22 and the washer 23 are inserted into the other end of the bar 21 and the nut 24 is screwed into the center hole jack 22 to make the PC steel rod 10b have a built-in tension.

By repeating such work, the underdrain or the underpass of a required length is formed. It is desirable that the recess 9 after the work is properly filled with mortar or the like to prevent the metal fittings from rusting.

[0027]

According to the present invention described above, since it is an integrated product in which a flexible connecting material is embedded, the moldability is excellent without stepwise concrete driving, and the manufacturing efficiency is improved. Further, since it is an integrated product, it is excellent in storability and transportability without adding reinforcement or a supporting member. And, since the breakage control unit can prevent the flexible connecting member from being broken when stress is concentrated and broken in the cross section, the effect of the flexible connecting member is not lost. Play.

Furthermore, since the flexible connecting member can expand and contract without breaking, it is possible to maintain the airtightness of the inside of the box culvert and prevent the deterioration of the waterproof property. Further, since the plate-like portion that projects to the front and the rear forms a void portion of the concrete cross section that receives a tensile force to concentrate the stress, it is easy to break during uneven settlement or the like. Furthermore, since the flexible connecting member can expand and contract, it is possible to prevent the flexible connecting member from breaking along with the breakage of concrete. And, the expansion and contraction member can expand and contract for uneven settlement,
It is possible to prevent a decrease in waterproofness between the box culverts.

[Brief description of drawings]

FIG. 1 is a sectional front view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is an enlarged cross-sectional view of the main part of FIG.

FIG. 4 is an enlarged sectional view of an essential part showing another example.

FIG. 5 (A) and (B) are explanatory views of action.

FIG. 6 is a sectional plan view (A), (C) showing another example of the flexible connecting member and its operation explanatory views (B), (D).

FIG. 7 is a schematic plan view showing an application example of the present invention.

FIG. 8 is a partial cross-sectional view of the breakage control unit.

9 is a partial perspective view of FIG.

FIG. 10 is a cross-sectional plan view of an underground structure such as an underdrain or an underpass in an application example of the present invention.

11 is a sectional view taken along the line BB of FIG. 9;

FIG. 12 is a sectional view showing a construction process of an underground structure.

FIG. 13 is a sectional view showing a construction process of an underground structure.

FIG. 14 is a sectional view showing a construction process of an underground structure.

FIG. 15 is a sectional view showing a construction process of an underground structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Box culvert for differential settlement etc. 2 ... Section 3 ... Fracture formation part 4 ... Flexible connection material 4a ... Cylindrical part 4b, 4e ... Plate part 4c ... Column part (anchor part) 4d ... Square column part (anchor part) ) 4f ... Hollow triangle 4g ... Hollow semicircle 5 ... Width groove 6 ... Corner built-up portion 7 ... Through hole 8 ... Break control portion 9 ... Recessed portion 10, 10a, 10b ... PC steel rod 15 ... Elastic body 30 ... Expansion / contraction member

Claims (5)

[Claims] 1. A box culvert made of cylindrical precast concrete for constructing an underground structure such as an underdrain or an underground passage, which has flexibility of a predetermined width parallel to the inner and outer surfaces in its annular cross section. The connecting material is embedded, and the fracture forming portion is formed in an annular shape in a cylindrical cross section along the substantially center line of the flexible connecting material, and the fracture forming portion and the inner and outer surfaces are formed when the subsidence occurs. A box culvert for measures such as differential settlement that is characterized in that stress is concentrated between the two to make it rupturable. 2. The flexible connecting member comprises a cylindrical portion, a plate-shaped portion that extends laterally around the cylindrical portion and extends forward or backward, or either forward or backward, and left and right parallel to the cylindrical inner and outer surfaces. The box culvert for preventing differential settlement according to claim 1, wherein the box culvert comprises a plate-like portion having a predetermined width and protrudingly provided so as to intersect with the plate-like portion. 3. The box culvert according to claim 2, wherein the flexible connecting member has an expanding and contracting portion in which the cylindrical portion is formed in a hollow substantially triangular shape or a half-moon shape. 4. A concave portion facing each other across the flexible connecting member and a through hole communicating between the concave portions are formed in a cross section, and a PC steel rod is inserted into the through hole to form a concave portion in the concave portion. 4. The box culvert according to claim 1, wherein the box culvert has a rupture control portion at which both ends or one end of the elastic body is compressibly interposed. 5. The box culvert according to claim 4, wherein the PC steel rod penetrates an expansion / contraction material interposed between end faces between the box culverts.