JPH04337200A - Jointing structure for underground construction receiving buoyancy - Google Patents

Abstract

PURPOSE:To realize cost reduction by conducting joining for only an insufficiency of building frame weight against buoyancy in such a way as to utilize continuous underground wall weight even in the case of ground subsidence, when a continuous underground wall and a building frame side wall are constructed in contact with each other and joined so that excavation amount is small and it is not necessary to make the thickness of a side wall and a bottom plate large. CONSTITUTION:A side wall 6 is constructed adjacent to a continuous underground wall 1, in a underground construction consisting of a bottom plate formed in contact with a bottom face of an excavated hole in ground and a building frame equipped with a side wall standing upwards from on outer periphery of this bottom plate. Steel pipes 3, 7 are projected as supporting members which are loosely fitted to this side wall 6 side and to the continuous underground wall 1 side respectively. The steel pipe 3 at the continuous underground 1 side is made with a large diameter which allows subsidence of the side wall 6 side. After the building frame is completed, a space between the steel pipe 3, 7 is fixed by grouting.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing underground structures such as underground tanks that are subject to buoyancy.

0002

[Prior Art] The dimensions of the members of underground structures such as underground tanks where buoyancy acts are determined from the viewpoint of safety against buoyancy and strength, but as structures become larger and deeper, As a result, the dimensions of members have come to be determined from the standpoint of safety against buoyancy rather than strength.

Taking underground tanks as an example, underground tanks have been developed in which a hole is formed by excavating the ground and the hole is partially or completely buried, but as shown in FIG. A continuous underground wall c was constructed at a slight distance from side wall a to surround side wall a and bottom slab b. The continuous underground wall c is for retaining earth and stopping water, and its lower end reaches the impermeable layer.

Another conventional example, as shown in FIG. 14, is one in which a continuous underground wall c and a side wall a are formed in contact with each other, and connecting reinforcing bars d are interposed between the two.

[0005]

[Problems to be Solved by the Invention] In the underground tank shown in FIG. 13, the buoyancy of groundwater is received by the side walls and bottom plate.
It must have a certain amount of weight. Therefore, the member thicknesses of the side wall a and the bottom plate b are determined from the viewpoint of stability against buoyancy rather than from the stress level (strength), so that the member thickness becomes large. Furthermore, since there is a gap between the side wall a and the continuous underground wall c, the amount of excavated soil increases, and an outer formwork for the side wall is also required. Furthermore, since the side wall a and the continuous underground wall c are separated from each other, the circumference of the continuous underground wall c becomes long.

In the underground tank shown in FIG. 14, since the side wall a and the continuous underground wall c are connected, the weight of the continuous underground wall c can be seen as the resistance force against the buoyancy of the underground tank, and the side wall a and There is no need to increase the thickness of the bottom plate b. Further, since the continuous underground wall c and the side wall a are formed in contact with each other, the amount of excavation is small, no formwork is required on the outside of the side wall, and the circumference of the continuous underground wall c can be small.

However, since the side wall a and the continuous underground wall c are connected to the continuous underground wall c by reinforcing bars d, if the ground is not solid and lacks supporting capacity, the weight of the underground tank frame is transferred to the continuous underground wall c. Since this is transmitted to the inner wall, a large number of joints using the reinforcing bars d must be provided, which increases costs. As structures become larger, the transmission force due to the weight of the underground tank structure is becoming larger compared to the lack of resistance to buoyancy, and the amount of reinforcing bars is often determined by the weight of the structure rather than the buoyancy. .

The object of the present invention is to eliminate the disadvantages of the conventional example, to form a continuous underground wall and a frame side wall in contact so that the amount of excavation is small and there is no need to increase the thickness of the side wall or bottom slab. And even if the ground subsides due to lack of supporting capacity when connected, underground structures that receive buoyancy can be connected so that the weight of continuous underground walls is used to compensate for the lack of buoyant weight, thereby reducing costs. The purpose of this invention is to provide a joint structure for this purpose.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a frame comprising a bottom plate formed in contact with the bottom of a hole excavated in the ground, and a side wall rising upward from the outer periphery of the bottom plate. In the underground structure, the side wall is formed adjacent to a continuous underground wall, and a supporting member that loosely fits or comes into contact with the side wall and the continuous underground wall is protruded from the side wall and the continuous underground wall,
In addition, the supporting members on the continuous underground wall side should be of a large diameter or extensible to allow the side wall to sink, and after the frame is completed,
The gist of this is to fix by grouting between the supporting members or within the supporting portion.

0010

[Operation] According to the present invention, during construction, the building frame sinks due to the increased load due to concrete pouring on the building frame, but no force is transmitted to the continuous underground wall. Then, after constructing the frame, a vertical connection can be obtained by grouting, and the weight of the continuous underground walls can be used as resistance against the buoyancy of the frame.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 9 to 12 are partial side views of each process showing one embodiment of the construction method of an underground structure subjected to buoyancy according to the present invention,
As shown in FIG. 9, a continuous underground wall 1 is constructed in a circular manner so as to surround the underground tank to be constructed first. This continuous underground wall 1 serves as a water stopper and earth retainer, and its lower end reaches the impermeable layer. As shown in FIGS. 1 and 2, a steel plate 2 is buried as a base in the vertically intermediate part of the continuous underground wall 1.
A short steel pipe 3 serving as a supporting member was provided to protrude horizontally from this iron plate 2.

As shown in FIG. 10, a hole 4 is formed by excavating the inside of the continuous underground wall 1. Next, as shown in FIG. 11, concrete is poured into the bottom of this hole 4 to form a bottom plate 5 so as to come into contact with the ground. Furthermore, a side wall 6 is raised upward from the outer periphery of the bottom plate 5. The side wall 6 is formed adjacent to the continuous underground wall 1 described above. An iron plate 2 is embedded as a base in the outer circumferential surface of the side wall 6, and a short steel pipe 7 as a support member is horizontally projected from the iron plate 2 and loosely fitted into the steel pipe 3.

The steel pipe 3 has a larger diameter than the steel pipe 7, and the loose fit is such that the side wall 6 sinks to ensure a gap that allows the steel pipe 7 to descend. Further, the steel pipe 7 is filled with concrete 8. Furthermore, near the outer peripheral portion of the steel pipe 7, a grout hose 9 that opens between the steel pipes 7 is buried in the side wall 6 side.

The side walls 6 are erected one after another to construct a frame with the bottom slab 5, but the ground sinks due to the weight of this frame, and the side walls 6
When the steel pipe 7 descends relative to the continuous underground wall 1, the position of the steel pipe 7 also moves from above to below within the steel pipe 3, as shown in FIGS. 3 and 4.

After the frame is completed, grout material 10 is poured between the steel pipes 3 and 7 using the grout hose 9, and the steel pipes 3 and 7 are fixed with this grout material 10. Also, Figure 12
As shown in the figure, a roof 11 is placed on the side wall 6, and an embankment 12 is placed around it.

As described above, the steel pipe 3 protruding from the continuous underground wall 1 and the steel pipe 7 protruding from the side wall 6 form a support that transmits a force in the vertical direction, and the continuous underground wall 1 responds to the buoyant force of the building frame. Weight can be used as resistance.

FIGS. 5 and 6 show a second embodiment of the present invention, in which an iron plate 2 serving as a base on the side of the continuous underground wall 1 includes an outer box 13a and a wall that moves downward with respect to the outer box 13a. A drawer-type extendable support member consisting of a removable inner box 13b is provided, and a grout hose 9 for injecting grout material into the outer box 13a and the inner box 13b is provided on the outer box 13a.

Furthermore, a box 14 filled with concrete 8 is protruded from the iron plate 2 serving as a base on the side wall 6, and the top surface of this box 14 is in contact with the bottom surface of the inner box 13b that is housed within the outer box 13a. Let them come into contact with you.

The steps are almost the same as those in the first embodiment, so illustrations are omitted, but when the side walls 6 are erected one after another and the frame is constructed with the bottom plate 5, the ground sinks due to the weight of the frame, causing the side walls to collapse. 6 lowers with respect to the continuous underground wall 1, the position of the box body 14 also lowers as shown in FIGS. 7 and 8, and the inner box 1
3b is pulled out.

After the frame is completed, grout 10 is poured into the outer box 13a and inner box 13b using the grout hose 9 and fixed.

[0021]

Effects of the Invention As described above, the method of constructing underground structures subjected to buoyancy according to the present invention allows the side walls and continuous underground walls to be formed close to each other, so that it is possible to reduce the amount of excavation and to construct continuous underground structures. The circumference of the wall can be shortened and construction costs can be reduced. Furthermore, since the side wall and continuous underground wall are connected, the buoyant force exerted by the bottom slab and side wall is transmitted to the continuous underground wall, so that the continuous underground wall also bears the resistance force against the buoyant force. Therefore, the thickness of the side walls and bottom plate can be made relatively small, and construction costs can be reduced.

[0022] Moreover, even if the ground sinks when the joint is made, the weight of the continuous underground wall is used to compensate for the lack of buoyancy in the weight of the main body, thereby minimizing the joint and reducing costs. It is possible to achieve down.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view of the main part before subsidence, showing a first embodiment of the construction method of an underground structure subjected to buoyancy according to the present invention.

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

FIG. 3 is a vertical sectional side view of the main part after subsidence, showing the first embodiment.

FIG. 4 is a view taken along line A-A in FIG. 3;

FIG. 5 is a longitudinal cross-sectional side view of the main part of the second embodiment before subsidence.

FIG. 6 is a view taken along line AA in FIG. 5;

FIG. 7 is a longitudinal sectional side view of the main part after subsidence, showing the second embodiment.

8 is a view taken along line AA in FIG. 7; FIG.

FIG. 9 is a side view of the first step showing the first embodiment of the method for constructing an underground structure subjected to buoyancy according to the present invention.

FIG. 10 is a side view of the second step of the first embodiment of the method for constructing an underground structure subject to buoyancy according to the present invention.

FIG. 11 is a side view of the third step showing the first embodiment of the method of constructing an underground structure subjected to buoyancy according to the present invention.

FIG. 12 is a side view of the fourth step showing the first embodiment of the method for constructing an underground structure subjected to buoyancy according to the present invention.

FIG. 13 is a partially vertical side view showing a conventional example.

FIG. 14 is a partially vertical side view showing another conventional example.

[Explanation of symbols]

1...Continuous underground wall
2...Iron plate 3...Steel pipe
4...hole 5...bottom plate
6...Side wall 7...
steel pipe
8... Concrete 9... Grout hose
10... Grout material 11... Roof

12... Embankment 13a... Outer box
13b...Inner box 14...Box body

Claims (2)

[Claims] Claim 1: In an underground structure having a frame having a bottom plate formed in contact with the bottom of a hole drilled in the ground, and a side wall rising upward from the outer periphery of the bottom plate, Forming the side wall, protruding support members that loosely fit into each other on the side wall side and the continuous underground wall side, and the support member on the continuous underground wall side has a large diameter to allow the side wall to sink. A joint structure for underground structures that is subject to buoyancy, characterized by the fact that after the frame is completed, the supporting members are fixed by grouting. Claim 2: In an underground structure having a frame including a bottom plate formed in contact with the bottom of a hole drilled in the ground, and a side wall rising upward from the outer periphery of the bottom plate, The side wall is formed, and a support member is provided protruding from the side wall side and the continuous underground wall side to abut each other, and the support member on the continuous underground wall side is extendable to allow the side wall to sink. , A joint structure for an underground structure that receives buoyancy, characterized by fixing the inside of this extensible support part by grouting after the frame is completed.