JPH0317311A - Continuous underground wall method - Google Patents

Abstract

PURPOSE:To ensure security and to reduce a construction period by constructing two cylindrical continuous underground walls opposed to each other at a certain interval so as to be closed in plane, and constructing a floor slab combined with the continuous underground walls to the bottom of the foundation formed by excavating between circumferential surfaces of them. CONSTITUTION:Cylindrical internal continuous underground wall 10 and external continuous underground wall 20 have different diameters with openings in the upper and lower ends, they are so constructed that their circumferential surfaces are closed in plane, and a circular bedrock held between the internal and exter nal continuous underground walls 10 and 20 is excavated in the shape of a spiral in the circumferential direction. Concrete is placed at the bottom, and a concrete floor slab 30 combined with the internal and external continuous underground walls 10 and 20 is formed to function as a strut. Then, after the excavation between the internal and external continuous underground walls 10 and 20 goes around, the lower part of the concrete floor slab 30 is excavated. According to the constitution, the concrete floor slab 30 functioning as the strut is extended to ensure security, to obtain many work places and to make it possible to reduce a construction period.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a continuous underground wall construction method that can be applied to various types of mountain retaining works or constituent materials of various structures such as underground storage tanks and artificial islands.

<Conventional Technology> Currently, the use of underground areas is attracting attention because of various restrictions when using land above ground.

Against this background, various construction techniques for continuous underground walls that can be constructed at great depths have recently been proposed.

Regarding conventional construction techniques of this type, it is known that the rotary excavation method allows construction of walls with greater thickness than the packet excavation method.

<Problems to be Solved by the Present Invention> The conventional continuous underground wall construction techniques described above have the following problems.

(a) As the depth increases, the wall thickness required to ensure the strength of the continuous underground wall also increases.

With current construction technology, the maximum wall thickness that can be constructed is 3m.
That's about it.

<Explanation> When the designed wall thickness exceeds 3 m, a construction method is adopted in which a series of excavation processes and concrete pouring are repeated several times, and reinforcement walls are covered on the inner and outer surfaces of the continuous underground wall.

However, with this construction method, the construction cost including reinforcement work is extremely high.

<C> The thicker the design wall thickness, the more industrial waste will be generated, which will increase the cost of processing the industrial waste.

For the reasons mentioned above, the current construction methods cannot adequately meet the ever-increasing demand for continuous underground walls at great depths.

Therefore, proposals for improvement techniques are desired.

<Object of the present invention> The present invention has been made to solve the above problems, and its purpose is to provide a continuous underground wall construction method that is excellent in construction efficiency and economy, and can shorten the construction period. Our goal is to provide the following.

<Configuration of the Present Invention> Hereinafter, a case of constructing a cylindrical continuous underground wall, which is an embodiment of the present invention, will be described with reference to the drawings.

Note that the continuous underground wall is not limited to a cylindrical shape, and can of course be applied to other shapes.

<B> Construction of a continuous underground wall First, as shown in Figures 2 and 3, a continuous underground wall with a double structure facing each other at a certain distance is constructed underground.

This double continuous underground wall consists of an internal continuous underground wall 10 and an external continuous underground wall 20 located outside of the internal continuous underground wall 10, both of which have a cylindrical shape with different diameters and open upper and lower ends. It has a shape.

That is, the internal continuous underground wall 10 and the external continuous underground wall 20 are as follows:
It is constructed so that the respective circumferential surfaces are in a planar closed relationship.

The internal and external continuous underground walls 10, 20 are constructed by known methods.

<Entrance> Continuing with wall-to-wall excavation, as shown in Figure 4, internal and external continuous underground walls 1
Excavating the annular ridge sandwiched between 0 and 20 in a spiral along the circumferential direction is continued.

<C> Formation of concrete slab As shown in Figure 4, internal and external continuous underground walls 10
, 20 are excavated and concrete is placed on the bottom of the pile, thereby forming a concrete floor slab 30 having an integral structure with the internal and external continuous underground walls 10 and 20.

The concrete slab 30 has internal and external continuous underground walls 10,
It functions as a strut between the 20 peripheral surfaces.

Concrete floor slab 3o is connected to internal and external continuous underground walls 10,
20, for example, as shown in FIG. 5, when constructing the internal and external continuous underground walls 10, 20, connecting materials 40 such as reinforcing bars are embedded in the planned connection points of the concrete slab 30. or internal and external continuous underground wall 10;
It is possible to employ a connection structure such as connecting the 20 corresponding points with reinforcing bars, or connecting screws or anchors.

Next, when the cast concrete slab 30 has developed strength, the lower surface of the concrete slab 30 is further excavated after one round of excavation between the internal and external continuous underground walls 10 and 2O.

By repeating the above excavation process and the forming process of the concrete slab 30 in parallel, a spiral concrete slab 30 is formed between the internal and external continuous underground walls 10 and 20.

By extending the concrete slab 30 in a spiral shape, a spiral space is formed between the circumferential surfaces of the internal and external continuous underground walls 10 and 20.

The spiral pitch of the concrete slab 30 is the same as that of each continuous underground wall 1.
It is determined by the wall thickness and diameter of 0 and 20, the design strength of the final structure, etc.

Finally, a spiral passage defined by the concrete slab 30 is formed between the circumferential surfaces of the internal and external continuous underground walls 10, 20.

<2> Internal Excavation After the internal continuous underground wall 10 and the external continuous underground wall 20 are integrated with the concrete slab 30 as shown in FIG. 6, the inside of the internal continuous underground wall 10 is excavated.

Various structures are constructed inside the internal continuous underground wall 10 depending on the purpose of use.

After completion, external forces will be dispersed and supported by the external continuous underground wall 20, concrete slab 30, and internal continuous underground wall 10, which are integrally constructed.

<Other Embodiments 1> In the above embodiments, a case was explained in which a single spiral concrete slab 30 was constructed between the circumferential surfaces of the internal and external continuous underground walls 10 and 20. It is also possible to construct multiple concrete slabs 30 in parallel.

Figure 7 shows the case where construction is carried out while excavating the upper and lower three stages as a group.

In the case of the figure, for example, when excavation is being carried out at the top A of the group, concrete is curing in the middle B of the group, and excavation is being carried out at the bottom C.

In the case of this embodiment, the work at the higher stage is always carried out before the work at the lower stage.

Further, the work areas can be combined into two levels (upper and lower) or four or more levels.

According to this embodiment, since there are many work areas, it is possible to significantly shorten the construction period.

Other Example 2> The spiral space between the circumferential surfaces of the internal and external continuous underground walls 10.20 can be used as a passageway, and can also be filled with concrete to form an integrated continuous wall. be.

<Other Embodiment 3> Three or more continuous underground walls may be formed, and a concrete slab may be constructed between the peripheral surfaces of each continuous underground wall.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

(A) In the present invention, if a thickness is required, this can be achieved by forming a plurality of thin continuous underground walls that can be constructed.

Therefore, it is now possible to construct walls with a wall thickness of 3 m or more, which was considered to be the limit with conventional construction techniques, and it can be used at great depths.

<Entrance> Continuous underground walls are formed in multiple layers, resulting in a high water-stopping effect.

〈C〉Since the concrete slab that functions as a strut is extended without excavating between the circumferential surfaces of the continuous underground wall, it is safer in comparison to the method of installing struts after all excavation is completed. It is.

(2) The spiral space between the continuous underground walls can be used as a passageway.

<E> When constructing between continuous underground walls, the construction period can be shortened because there are many work areas.

(f) Since the thickness of each continuous underground wall can be designed to be thin, the cost of processing industrial waste can be reduced.

<G> It is possible to apply it to offshore construction such as offshore platforms.

[Brief explanation of drawings]

Fig. 1 2 An overall partially cutaway view of an underground structure constructed using the continuous underground wall according to the present invention Fig. 2: An explanatory diagram of the construction method during construction of internal and external continuous underground walls Figure 3: Plan view of Figure 2 Figure 4: Cross-sectional view when constructing a concrete slab by excavating the circumference of the internal and external continuous underground walls Figure 5: Fixing of the concrete slab Explanatory diagram of structural example Figure 6: Cross-sectional view of internal continuous underground wall during excavation Figure 7: Explanatory diagram of other examples

Claims (1)

[Claims] (1) Two continuous underground walls are constructed in a planar closed relationship such as cylindrical or square shapes that face each other with a certain distance between them, and the circumferential surfaces of the two continuous underground walls are After excavating between the circumferential surfaces of both continuous underground walls, a slab is constructed on the bottom of the ground created by excavating between the circumferential surfaces of both continuous underground walls, and a slab is constructed integrally with both continuous underground walls. A continuous underground wall construction method, in which the lower surface of the floor slab is reached, and the floor slab is successively extended while excavating below the floor slab to construct a continuous underground wall with an integrated structure.