JPH0219251B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a side wall structure in a circular underground structure in which a retaining wall formed by a cast-in-place concrete column row continuous wall is used as the main structure.

(Prior technology) The conventional construction method for underground structures is as described in Foundation Works VOL.12 No.11 (1980-11-15) P.32, in which the tip of a rotating hollow shaft excavates the ground. A construction method in which prepact cement is injected from the tip of a mixing blade attached to the pile while stirring and mixing with the surrounding soil to build piles using local soil as aggregate, or using mortar and local soil that increases the strength of column piles. There is a method of constructing cast-in-place piles in rows of columns and using them as a retaining wall using the replacement method, which involves inserting reinforcing bar cages or shaped steel. Afterwards, a structure was constructed inside.

(Problems to be Solved by the Invention) Conventionally, in underground structures, retaining walls made of continuous cast-in-place concrete column rows with reinforcing bars or shaped steel inserted have sufficient vertical bending strength and compression. Despite its strength, it lacked horizontal structural members and lacked circumferential rigidity, so it served only as a temporary structure and a retaining wall.

(Means and effects for solving the problem) In view of the above-mentioned circumstances, the present invention aims to utilize a retaining wall made of a cast-in-place concrete column row continuous wall and a ring beam as a support as the main structure, In the side wall structure of a circular underground structure, a cast-in-place concrete column continuous wall, a ring beam, and a composite wall made of post-cast side wall concrete are provided, and the cast-in-place concrete pile has a core material joined with dowels inserted. a concrete column continuous wall arranged in a circular shape; a ring beam contacting the inner side of the concrete column continuous wall and arranged horizontally at intervals in the vertical direction; and a ring beam contacting the inner side of the concrete column continuous wall It consists of a composite wall made of concrete with side walls cast in a cylindrical shape.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. Fig. 1 shows a state in which the cast-in-place concrete column continuous wall and ring beam function as a retaining wall, and Fig. 2 is an explanatory view after pouring side wall concrete.

In the side wall structure of the present invention, cast-in-place concrete is first constructed in a row of columns, and the cast-in-place concrete columns are secured by a continuous wall 1 in which an H-shaped steel 2 to which dowel reinforcing bars 7 are welded in advance is inserted as a core material. The wall is excavated one by one using the ring beam 3 as support. The ring beam 3 is made of a material that can withstand axial compressive force and bending in the horizontal plane, in order to resist the bending moment in the horizontal plane caused by compressive force in the circumferential direction and uneven earth pressure generated in a cylindrical structure subjected to external pressure. In the example, H-beam steel was used. During excavation, the dowel reinforcing bars 7 of H-beam steel in the cast-in-place concrete column row continuous wall 1 are scooped out, and post-cast side wall concrete 8 is poured so as to wrap around the ring beam 3.

That is, first, enough dowel reinforcing bars 7 to establish a composite wall structure are welded to the H-shaped steel 2 to be inserted into the cast-in-place concrete column continuous wall 1, and the cast-in-place concrete column continuous wall 1 is precisely shaped into a circular shape. Build a guide ring 4 for good construction. After that, immediately after cutting the ground with an auger according to the guide ring 4 and replacing the local soil with mortar, the cast-in-place concrete column row is completed by inserting the H-beam 2 to which dowel reinforcing bars 7 have been welded in advance. The continuous wall 1 is used as a retaining wall. Thereafter, a portion of the inside of the retaining wall is excavated in order to install a ring beam 3 as a support, a bracket 5 for installing the ring beam 3 is attached, and the first stage ring beam is installed. At this time, the ring beam 3 is connected to the retaining wall so that the force is transmitted from the retaining wall to the ring beam 3.
Mortar is filled between the two as a bonding material 6. Then, primary internal excavation is performed to scoop out the dowel reinforcing bars 7, and subsequent excavations are performed in this order. After the excavation is completed, circumferential reinforcing bars 9 and vertical reinforcing bars 10 are arranged, and side wall concrete 8 is placed so as to wrap around the ring beam 3. As a result, in the vertical direction, the H-shaped steel 2 and vertical reinforcing bars 1 inside the retaining wall
0 and post-cast side wall concrete 8, and in the circumferential direction, steel reinforced concrete consisting of H-shaped steel ring beams and circumferential reinforcing bars 9 has been completed, cast-in-place concrete column continuous wall 1, ring beam 3 A side wall structure consisting of the side wall concrete 8 and post-cast side wall concrete 8 is constructed.

Due to this side wall structure, when it is used as a retaining wall as shown in Figure 1, it is in a stress state corresponding to the earth pressure and water pressure during construction, and after the side wall concrete is poured as shown in Figure 2. The structure is designed to generate incremental stress corresponding to external forces (earthquake earth pressure, internal pressure, etc.) applied after completion, and to be able to resist the stress state that is the sum of the residual stress during construction and the incremental stress after completion. Therefore, compared to conventional construction methods in which external forces are resisted only by side wall concrete, with this side wall structure, the thickness of post-cast side wall concrete can be greatly reduced.

(Effects of the Invention) As explained above, the side wall structure according to the present invention makes it possible to use the retaining wall made of continuous walls of cast-in-place concrete columns, which have been conventionally used as temporary structures, as part of the main structure. Compared to the case where the retaining wall is simply used as a temporary structure, the thickness of post-cast side wall concrete can be significantly reduced, which is effective in significantly reducing the amount of concrete and reinforcing bars used in the main structure.

[Brief explanation of drawings]

Figure 1 shows a cast-in-place concrete column row continuous wall and ring beam functioning as a retaining wall, and Figure 2 shows a side wall after pouring concrete. . 1...Cast-in-place concrete columns continuous wall, 2...
...H-beam, 3...Ring beam, 4...Guide ring, 5...Bracket, 6...Joining material, 7...
Dowel reinforcing bars, 8...Side wall concrete, 9...Circumferential reinforcing bars, 10...Vertical reinforcing bars.

Claims (1)

[Claims] 1. In a circular structure constructed underground, a concrete column continuous wall in which cast-in-place concrete piles with dowel-bonded core material inserted are arranged in a circular shape, and a concrete column continuous wall in contact with the inside of said concrete column continuous wall in the vertical direction A circular underground structure characterized in that the main structure is a composite wall made of ring beams arranged horizontally at intervals, and side walls made of concrete poured in a cylindrical shape in contact with the inside of the concrete column continuous wall. Side wall structure of formula structure.