JPH0547694B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to culvert blocks, commonly called box culverts or arch culverts, in which a large number of culverts are installed in series underground to form culverts, water supply and sewage systems, etc.

[Conventional technology]

The basic structure of the culvert block used for the above purpose has conventionally been a box culvert as shown in FIG. 5a or an arch culvert as shown in FIG. 6a. It has a cylindrical structure with side walls 2, 2 on both sides of the bottom plate 1 and a top plate 3 on the top thereof. The respective bending moment diagrams are shown in FIGS. 5b and 6b. It is characterized by a large bending moment at the center of the bottom plate 1. The main reason for this is that almost the entire surface of the bottom plate 1 acts as the pressure receiving surface P.

[Problems to be Solved by the Invention] In the past, underdrain blocks were buried relatively shallowly, usually about 3 to 4 m, but recently they have become deeper, reaching 10 to 30 m. Therefore, in order to create a structure that can withstand bending moments, in the case of conventional structures, the bottom plate had to be made thicker. Since it would not last unless it was thickened, it had the disadvantage of requiring a large amount of concrete material and reinforcing steel.

[Means to solve the problem]

Therefore, as a result of various studies in the direction of reducing the stress near the center of the bottom plate, we found that there are side walls 2 and 2 on both sides of the bottom plate 1.
In the above-mentioned culvert block in which the top plate 3 is provided on the upper part of the culvert block, the top plate 3 has an upwardly curved arch shape, and the side walls 2 and 2 have a side wall with a width approximately the same thickness as the lower part of the side wall. The above-mentioned difficulty was solved by providing the legs 4, 4 which protrude from the bottom surface of the bottom plate 1 over the entire length and have pressure-receiving surfaces that are substantially parallel to the bottom plate surface. If the width of the legs 4 becomes too wide than the side wall thickness, there will be no difference in weight from conventional ones, and the meaning of providing the legs will be halved. Conversely, if the width of the leg portions becomes too narrow, the pressure receiving area becomes small and the leg portions 4 are crushed. In order to obtain an effective pressure receiving area of the leg portion, it is necessary that the leg portion 4 extends over the entire length of the side wall, and that the pressure receiving surface P of the leg portion 4 is substantially parallel to the bottom plate surface. Further, the object of the present invention is achieved when the installation surface is hard, such as on rock or concrete.

[Effect]

As in the present invention, the leg portion 4 has a pressure-receiving surface at the lower part of the side walls 2, 2, which has a width that is approximately the same thickness as the side wall, protrudes from the bottom surface of the bottom plate 1 over the entire length of the side wall, and is substantially parallel to the bottom plate surface. , 4, the load applied to the underdrain block becomes stress on the pressure receiving surface P of the legs 4, 4, and as shown in FIG. 4, there is an effect that the bending moment at the center of the bottom plate 1 is minimized.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view of an arched culvert block according to a first embodiment of the present invention. Figure 2 is the same side view, Figure 3
The figure is a bottom view of the same, and FIG. 4 is a bending moment diagram of the same underdrain block. This culvert block has an arch shape with side walls 2, 2 on both sides of a bottom plate 1, and a top plate 3 curved upwards on the top thereof, and has concave-convex fitting parts 5, 6 is provided. The cavities created by connecting them become culverts and can be used for various types of piping such as water supply and drainage channels, water pipes, and electric cables. In addition to this structure, legs 4, 4 are provided at the lower part of the side walls 2, 2, extending over the entire length of the side walls and having a width approximately equal to the thickness of the side walls. When the legs 4, 4 are provided at the bottom of the side walls 2, 2 with a width that is approximately the same thickness as the side walls, the bending moment is almost uniform over the entire area of the bottom plate, as shown in Fig. 4. Figure 5b, Figure 6b
This is completely different from the conventional situation where the central part is large as shown. Therefore, as shown in FIG. 1, we were able to create an underdrain block that could withstand high loads without making the bottom plate 1 thicker. The deeper the culvert block is buried in the soil, the greater the difference in the thickness of the bottom slab becomes compared to conventional products. As described above, the underdrain block of the present invention has side walls 2,
The present invention is characterized in that leg portions 4, 4 are provided at the lower part of the side wall over the entire length of the side wall and have a width that is approximately the same as the side wall, so it is not limited to the above embodiment. However, the present invention also includes curved shapes used at corners and curved parts, and types in which the bottom plate 1, side walls 2, 2, and top plate 3 are each formed separately and assembled at the time of construction. .

【Effect of the invention】

Since the present invention has the structure as detailed above,
Even if buried deep underground where the earth pressure is extremely high, the top plate 3
The bending moment at the center of the bottom plate is minimized because the load on the underdrain block is borne by the pressure-receiving surface of the leg. Therefore, the thickness of the member in the middle part of the bottom plate can be made thinner, and the amount of reinforcement can be reduced, resulting in a structure that can withstand high loads, yet is lightweight and has the effect of lowering manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a front view of a culvert block according to a first embodiment of the present invention. FIG. 2 is a side view of the same, and FIG. 3 is a bottom view of the same. FIG. 4 is a bending moment diagram of the same underdrain block. 5a and 6a are front views of conventional underdrain blocks, and FIGS. 5b and 6b are bending moment diagrams thereof. 1...Bottom plate, 2...Side wall, 3...Top plate, 4...
Leg, P...pressure receiving surface.

Claims (1)

[Claims] 1. In a culvert block consisting of side walls 2, 2 on both sides of the bottom slab 1 and a top slab 3 on the top thereof, the top slab 3 is curved upward in an arch shape, and the bottom of the side walls 2, 2 has a wall approximately the same size as the side wall. An underdrain block characterized by being provided with leg parts 4, 4 which protrude from the bottom surface of the bottom plate 1 over the entire length of the side wall and have a pressure receiving surface substantially parallel to the bottom plate surface.