JP2657671B2 - Reconstruction method for existing structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention uses an existing structure on the ground and constructs a foundation for a structure for rebuilding in the underground part of the existing structure. Concerning the construction method.

<Conventional technology> In order to rebuild existing structures such as apartment buildings over a large area, after relocating or dismantling existing structures existing on the ground, excavation and foundation work will be performed. Above the ground, and finally, above the foundation.

<Problems to be Solved by the Present Invention> The above-mentioned conventional techniques for rebuilding an existing structure have the following problems.

<B> During the rebuilding work of the existing structure, the existing structure cannot be used.

Therefore, there is a demand for a technique for rebuilding the existing structure while maintaining the existing structure.

<B> In general, rebuilding of existing structures requires some temporary space around the ground.

In addition, a temporary relocation space for temporarily placing various items in the existing structure is also required.

However, it is becoming more difficult to secure these spaces in recent years when land prices are rising.

<Object of the present invention> The present invention has been made in view of the above points, and an object of the present invention is to provide a method for rebuilding an existing structure as follows.

<a> Reconstruction work can be performed while maintaining the existing structure.
Reconstruction method for existing structures.

<B> A method of rebuilding existing structures that allows effective use of land.

<Configuration of the Present Invention> Hereinafter, an embodiment of a method for rebuilding an existing structure according to the present invention will be described with reference to the drawings.

<B> Tunnel excavation (Fig. 2) A shaft 1 will be constructed around the planned reconstruction site.

 At this time, the water stop wall 10 is constructed as needed.

Then, a tunnel 2 is excavated from the shaft 1 to the entire underground portion of the planned reconstruction site.

The excavation method of the tunnel 2 is selected according to the foundation type of the existing structure 3 erected on the ground.

As an excavation method, for example, when the foundation type of the existing structure 3 is a direct foundation, a shield method or a messel method is adopted, and when the foundation type is a pile foundation, a messel method or the like is adopted.

When excavating the tunnel 2, auxiliary methods such as a pipe roof method and a chemical liquid injection method are used as needed.

When the foundation type of the existing structure 3 is a pile foundation, the existing pile 31 and the tunnel 2 forming a part of the foundation of the existing structure 3 are used.
However, in order to prevent land subsidence, excavation is performed with the existing pile 31 penetrating the tunnel 2.

<B> Construction of foundation pile (Fig. 2) Tunnel 2 by reverse circulation method
Of the foundation pile 4 extending downward.

<C> Construction of PC slab (Figs. 2 and 3) Next, a PC slab 21 is constructed on the slab surface of the tunnel 2.

The PC slab 21 is constructed integrally with the foundation pile 4 and the existing pile 31.

The PC slab 21 functions as a top plate for preventing the collapse of earth and sand when the underground is constructed, and finally becomes a constituent material of the structure.

The construction method of the PC slab 21 is as follows. After the PC steel material is arranged in a loop shape together with the reinforcing steel so as to surround the foundation pile 4 on the slab surface of the tunnel 2 and concrete is poured into the slab, the PC steel material is formed in the middle of the slab. Can be adopted a method of fixing the tension.

As a method of introducing the prestress of the PC slab 21, a known well-known method of introducing the prestress is adopted in consideration of the height of the tunnel 2, the construction range, and the like.

Also, if necessary, the upper cavity in the tunnel 2 is filled with foam mortar.

<D> Excavation under the slab (Fig. 4) After constructing the PC slab 21 integrated with the foundation pile 4 group, the PC
The underground space 5 is formed by excavating below the slab 21.

Since the total load above the PC slab 21 is supported by the group of foundation piles 4 integral with the PC slab 21, the collapse of the underground space 5 during excavation is prevented.

In the case of excavation work below the PC slab 21, when a method of constructing in advance a soil excavation gallery communicating with the underground space 5 is adopted, a large amount of earth removal work can be performed with high efficiency.

<E> Construction of an underground facility (Fig. 5) An underground facility 7 is constructed by casting concrete on the inner surface of the underground space 5.

Then, the facility of the existing structure 3 on the ground side is moved to the underground facility 7 as necessary.

<E> Construction of Ground Facility (FIG. 6) Finally, a ground facility 8 is constructed above the underground facility 7.

The ground facility 8 may be constructed by sequentially removing the existing three groups of structures, or by removing the existing three groups at a time.

<Effects of the Invention> Since the present invention has been described above, the following effects can be obtained.

<a> The foundation work of the rebuilding structure can be performed while maintaining the existing structure on the ground.

In addition, since the ground facility is constructed after the underground facility of the reconstructed structure is completed, the period during which use of the existing structure is stopped can be minimized.

<B> The completed underground facilities can be used as a relocation space for existing structures on the ground side.

<C> Temporary space around the ground can be minimized.

<D> Effective use of land above ground can be achieved.

<E> PC slabs can be used as cut-off beams for water and earth retaining walls, and ultimately can be effectively used as part of structures.

<F> Suitable for rebuilding large-scale markets and housing complexes.

[Brief description of the drawings]

Fig. 1: Explanatory drawing of one embodiment according to the present invention, showing a partial cross-sectional view when constructing an underground facility Fig. 2: Longitudinal cross-sectional view when tunnel excavation Fig. 3: Tunnel longitudinal cross-section when constructing PC slab Fig. 4: Longitudinal section when excavating under PC slab Fig. 5: Longitudinal section when constructing an underground facility Fig. 6: Cross section when constructing a ground facility

Continuation of front page (72) Inventor Naoto Takami 1-25-1, Nishishinjuku, Shinjuku-ku, Tokyo Inside Taisei Corporation (56) References JP-A-2-20768 (JP, A)

Claims (1)

(57) [Claims] A tunnel is excavated over the entire underground part of the planned rebuilding site while maintaining the existing structure on the ground, and a foundation pile extending downward on the slab surface of the tunnel is constructed. Then, construct a PC slab that has an integral structure with the foundation pile and introduces prestress, and constructs an underground facility by excavating below the PC slab while supporting the ground with the foundation pile group via the PC slab Then, the existing structure on the ground is removed, and a ground facility integrated with the underground facility is constructed while removing the existing structure.