JP2757208B2 - Continuous underground wall construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a continuous underground wall construction method applicable to various types of construction work such as shore excavation or an underground storage tank or an artificial island.

<Conventional technology> At present, there are various restrictions on land use on the ground side, and the use of underground parts is drawing attention.

Against this background, there have recently been proposed various techniques for constructing a continuous underground wall capable of handling a large depth.

Regarding this kind of conventional construction technology, it is known that the rotary excavation method can construct a wall having a larger wall thickness than the bucket excavation method.

<Problems to be Solved by the Present Invention> The above-described conventional technology for constructing a continuous underground wall has the following problems.

<B> As the depth increases, the wall thickness necessary to secure the strength of the continuous underground wall also increases.

With the current construction technology, the maximum wall thickness that can be constructed is 3 m
It is about.

<B> If the design wall thickness exceeds 3m, a series of excavation processes
A concrete placement method is repeated several times to cover the inner and outer surfaces of the continuous underground wall with a reinforcing wall.

However, in this construction method, construction costs including reinforcement work are very expensive.

<C> Since the amount of industrial waste generated increases as the design wall thickness increases, the cost of treating industrial waste increases.

<D> For the above reasons, the current construction methods cannot sufficiently meet the increasing demand for continuous underground walls for large depths.

 Therefore, a proposal of the improvement technique is desired.

<Object of the present invention> The present invention has been made to solve the above problems, the purpose of which is excellent in workability and economy,
Another object of the present invention is to provide a continuous underground wall construction method capable of shortening the construction period.

<Configuration of the present invention> Hereinafter, an embodiment of the present invention with reference to the drawings,
A case where a cylindrical continuous underground wall is constructed will be described.

The continuous underground wall is not limited to a cylindrical shape,
Of course, it can be applied to other shapes.

<A> Construction of continuous underground wall First, as shown in FIGS. 2 and 3, a continuous underground wall having a double structure facing the surface at a predetermined interval in the underground is constructed.

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

In other words, the inner continuous underground wall 10 and the outer continuous underground wall 20 are constructed such that their respective peripheral surfaces are in a planarly closed relationship.

The inner and outer continuous underground walls 10, 20 are constructed by known methods.

<B> Excavation between walls Next, as shown in Fig. 4, internal and external continuous underground walls
Continue to excavate the circular ground between 10 and 20 spirally along the circumferential direction.

<C> Formation of concrete floor slab Similarly, as shown in Fig. 4, internal and external continuous underground walls 1
Concrete is poured into the bottom of the ground formed by excavation between 0 and 20 to form a concrete floor slab 30 integrally formed with the inner and outer continuous underground walls 10 and 20.

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

Concrete floor slab 30 is connected to the inner and outer continuous underground walls 10, 20
For example, as shown in FIG. 5, when constructing the inner and outer continuous underground walls 10 and 20, a connecting member 40 such as a reinforcing bar is buried in a portion to be connected to the concrete slab 30. Alternatively, a connection structure such as connecting a reinforcing bar or connecting a screw or an anchor by connecting a corresponding portion of the inner and outer continuous underground walls 10 and 20 can be adopted.

Next, at the stage where the strength of the concrete slab 30 is developed, the excavation between the internal and external continuous underground walls 10 and 20 is completed, and then the lower surface of the concrete slab 30 is excavated.

By repeating the above excavation step and the step of forming the concrete slab 30 in parallel, the inner and outer continuous
A spiral concrete floor slab 30 is formed between 10 and 20.

By spirally extending the concrete floor slab 30, a spiral space is formed between the peripheral surfaces of the inner and outer continuous underground walls 10, 20.

The spiral pitch of the concrete floor slab 30 is
It is determined by the wall thickness and diameter of 0 and 20 and the design strength of the final structure.

Finally, a spiral path defined by the concrete slab 30 is formed between the inner and outer continuous underground walls 10 and 20.

<D> Internal excavation After the internal continuous underground wall 10 and the external continuous underground wall 20 are integrated by the concrete slab 30, as shown in FIG.
The inside of the internal continuous underground wall 10 is excavated.

Various structures are constructed inside the internal continuous underground wall 10 according to the purpose of use.

The external force after completion is distributed and supported by the external continuous underground wall 20, the concrete slab 30, and the internal continuous underground wall 10 of the integral structure.

<Other Example 1> In the above-described example, the case where a single spiral concrete floor slab 30 is constructed between the inner and outer continuous underground walls 10 and 20 is described. The strip concrete slabs 30 can also be constructed in parallel.

FIG. 7 shows a case where the construction is performed while excavating the upper and lower three steps as a group.

In the case of the figure, for example, when excavation is being performed at the uppermost stage A of the group, concrete curing is being performed at the middle stage B, and excavation is being performed at the lowermost stage C.

In the case of this embodiment, the work of the upper stage always proceeds before the work of the lower stage.

In addition, the work location can be combined in two steps, four steps or more.

According to the present embodiment, since a large number of work locations can be obtained, it is possible to greatly shorten the construction period.

<Other Embodiment 2> The spiral space between the inner and outer continuous underground walls 10, 20 can be used as a passage, or can be filled with concrete to form an integral continuous wall. .

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

<Effects of the Present Invention> The present invention has the following effects.

<A> In the present invention, when a thickness is required, it can be dealt with by forming a plurality of thin continuous underground walls that can be constructed.

Therefore, it is possible to construct a wall with a thickness of 3 m or more, which was limited by the conventional construction technology, and it can be used at a large depth.

<B> Since the continuous underground wall is formed in multiple layers, a high water stopping effect can be obtained.

<C> Since the concrete slab that exerts the girder function is extended while excavating between the peripheral surfaces of the continuous underground wall, it is more advantageous in terms of safety than the method of applying the girder after all excavation is completed. is there.

<D> The spiral space between the peripheral surfaces of the continuous underground wall can be used as a passage.

<E> When constructing between continuous underground walls, the work period can be shortened because more work locations can be taken.

<F> Since the thickness of each continuous underground wall can be designed to be thin, the cost of treating industrial waste can be reduced.

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

[Brief description of the drawings]

Fig. 1: Overall view of a part of an underground structure constructed using the continuous underground wall according to the present invention. Fig. 2: Explanatory drawing of the construction method, when an internal and external continuous underground wall is constructed. Fig. 3: Plan view of Fig. 2 Fig. 4: Cross section when constructing concrete slab by excavating the inner and outer continuous underground wall Fig. 5: Fixing of concrete slab Illustration of structural example Fig. 6: Cross-sectional view at the time of excavation in the internal continuous underground wall Fig. 7: Illustration of other embodiments

Claims (1)

(57) [Claims] 1. A construction in which two continuous underground walls are constructed so as to have a planarly closed relationship such as a tubular shape or a rectangular shape facing each other at a predetermined interval, and a peripheral surface of the two continuous underground walls. In this method, a spiral slab is excavated downward in a spiral shape, and a spiral floor slab is integrated with the continuous underground wall on the bottom of the ground formed by excavating between the peripheral surfaces of both continuous underground walls. In the second and subsequent turns of the spiral, the existing floor slab is used as a ceiling plate, and excavation is performed below the floor slab to construct a continuous underground wall having an integral structure.