JPS63226407A - Underground continuous wall construction work - Google Patents

Abstract

PURPOSE:To enhance the effect of water stopping by using an expanded concrete for the joints of underground continuous walls. CONSTITUTION:Reinforcing bars are set in a trench excavated in the ground, and concrete is placed in a repeating manner to form sideward walls 2 connected. In this case, an expansive concrete 1' to be easily expanded and hardened as such during hardening period is used. The aperture in the joints of wall panels can thus be greatly reduced and the water-stopping effect of the walls can be improved to a great extent.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention involves excavating a continuous trench-like hole in the ground, building a continuous reinforced concrete wall in the hole, and constructing an earth retaining wall, a water-stopping wall, etc. Concerning underground continuous wall construction methods for constructing underground structural walls, etc.

(Prior Art) For underground continuous walls, there are two methods of joining a trailing panel to a leading panel: the interlocking pipe method and the cutting joint method.

The former interlocking pipe construction method involves inserting locking pipes at both ends of the preceding Banerue area, excavating the section partitioned by the locking pipes, pouring concrete and constructing the preceding panels, and then pulling out the locking pipes. This method involves excavating the trailing section and constructing the trailing panels.

In addition, in the latter cutting joint construction method, the preceding work section is excavated in the shape of a rectangular parallelepiped, concrete is poured, and the preceding panel is constructed, and then the subsequent work section is excavated, and the exposed end of the preceding panel is cut with a hydrocutter etc. After removing weak parts such as defective concrete at the joints,
This is a construction method that involves pouring concrete and joining the trailing panels.

In addition, there are other construction methods, such as wrapping the horizontal reinforcing bars using special joint members, or using a PC joiner (1-inch type steel joiner). All of these have been established as different construction methods in that the joining methods between the leading panel and the trailing panel, that is, the elements, are different. In addition, various efforts have been made to facilitate the implementation and construction of the joining means and to improve the bonding strength between the leading panel and the trailing panel.

(Problems to be solved by the invention) However, in any of the construction methods, water may leak from the joints between elements, and slime can get around during construction. Various efforts have been made.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a simple underground continuous wall construction method that can strengthen the connections between elements and obtain a water-stopping effect.

(Means for solving the problem) In this construction method, the process of erecting reinforcing bars in trenches excavated underground and then pouring concrete is repeated to connect the walls in the horizontal direction. Volume expansion occurs during the process,
They used expanded concrete that hardens as it is.

(Function) The expansion element is obtained using expansion cement mixed with an expansion agent. This expansive cement consists of Portland cement and calcium sulfoaluminate (3Ca 0-AI 2
0x ・Ca 804 ) or calcined and pulverized Bortland Talin containing calcium sulfoaluminate. When mixed with water, ettringite or calcium hydroxide is produced through a hydration reaction, which is It acts as an expansion source and causes the concrete to expand after it has set.

The expansion action causes compression between the elements, and prestress is also applied to the elements themselves, creating a degree of adhesion that sufficiently absorbs free contraction after initial expansion. This free expansion strain is approximately 500×10 −6 (1).

Therefore, if the panel width is 5 (IIl), the amount of elongation Δl is Δf-5×500xlO-'-2,5(n+m), so the gap between the leading panel and the trailing panel is made with sufficient pressure. In close contact.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1(a) and 1(b) are plan views of an underground wall formed by the construction method of the present invention, in which each element 1 is continuously connected and joined in the longitudinal direction to form an underground continuous wall 2. Each element 1 may be constructed by alternately connecting elements 1 made of ordinary concrete and elements 1' made of expanded concrete, or may be composed only of elements 1'.

This will be explained in more detail below in FIG.

In this embodiment, leading walls are constructed intermittently by placing concrete in vertical holes that are intermittently excavated, leaving the intermediate ground, and the intermediate ground between the constructed leading walls is excavated. , is a construction method in which the end face of the leading wall is cut and excavated to expose the roughened joint surface, and concrete is poured into this intermediate hole to connect the trailing wall to the leading wall. be.

First, in Fig. 2, the leading wall 3 constituting one element of the underground continuous wall is made of ordinary concrete reinforced with steel bars in a deep vertical hole 5 that is intermittently excavated, leaving an intermediate ground 4. It was constructed intermittently by pouring concrete into each.

A groove 6 is set along the longitudinal direction in the center of the pant joining part that contacts the trailing wall of the leading wall 3.

Next, an excavated vertical hole is formed in the intermediate ground 4, as shown in FIG. During this excavation, in the stabilizing liquid 7 filled in the vertical hole, the end face of the joint part of the leading wall 1 and the part of the groove 6 are roughened by a cutting means such as a drum cutter. Cut. As a result, an uneven surface 8 is formed at the joining portion of the leading wall 3, and a mortise hole 9 having an uneven surface 8 is formed in the longitudinal direction at the position of the groove 6.

Next, as shown in FIG. 4, by pouring expanded concrete reinforced with reinforcing steel inside the intermediate vertical hole, the joint portion between the ordinary concrete leading wall 3 and the expanding concrete trailing wall 10 is made into a joint. A joint structure is formed by the roughened uneven surface 8 and the mortise 9, and the joint is integrally joined.

(Effects) As explained in detail above, according to the construction method of the present invention, since expanding concrete is used, the volumetric expansion of concrete can be achieved without using shear connectors or reinforcing steel materials at the joints of underground continuous walls. This creates a strong press-fit between the panel joints and creates prestress between the panels. Therefore, the gap between the panel joints is extremely small, and it is possible to obtain an underground continuous wall with significantly improved water drainage effect.

[Brief explanation of the drawing]

FIG. 1 is a plan view for explaining an embodiment, and FIGS. 2 to 4 are plan views illustrating the construction order of the construction method of the present invention.

Claims (1)

[Claims] In this construction method, the process of placing reinforcing bars in a trench drilled underground and then placing concrete is repeated, and the walls are successively connected laterally.Volume expansion occurs during the hardening process, and the concrete hardens as it is. An underground wall construction method characterized by the use of expanded concrete.