JPH0369720A - Method of building annular beam for underground continuous wall - Google Patents

Abstract

PURPOSE:To enable a continuous wall and beams to be integrally built by a method wherein a pressure is exerted on the end surface of each of unit precast beams, arranged along the inner wall of an underground continuous wall, by means of a jack, and the gaps between the beams are filled with a non-contraction grout material. CONSTITUTION:A reinforcing bar cage is inserted in the annular excavated ditch of a ground, and concrete is placed to build an underground continuous wall A. After the inner ground of the continuous wall A is excavated, the given number of arcuate unit precast beams 1 are arranged along the inner wall of the continuous wall A in a manner to form an annular shape. After a flat jack 2 is located between the end surfaces of the beams 1, a pressure is exerted on the beams 1 by means of the jack 2 to introduce a prestress. The gaps between the beams 1 are filled with a non-contraction grout material 3. A similar work is orderly repeated the given number of times along with excava tion of a ground.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method of constructing an annular girder in an annular underground continuous wall.

Prior Art and Problems to be Solved by this Invention When constructing a deep, large-diameter shield shaft, an underground tank, or a final waste disposal site using an underground continuous wall, roots are required to reinforce the underground continuous wall. In other words, while excavating the ground, we can pull out the necessary reinforcing bars that have been placed in the underground wall in advance, or drive anchors, arrange the reinforcing bars, set up formwork, and pour in-place concrete. It requires pouring, which requires time and effort for construction. Therefore, it is desirable to attach prefabricated annular girders to the diaphragm wall.

By the way, as a construction method of this type, a method is proposed in which an annular girder is placed inside the sheet pile wall and a pressure device is interposed between the sheet pile wall and the annular girder to introduce prestress to the annular girder.
Although it is disclosed in Japanese Patent No. 789, there is a problem in that a gap is created between the sheet pile wall and the annular girder.

The purpose of this invention is to devise a method for introducing prestress that does not create the above-mentioned gap, and to develop a method for closely adhering and integrating the underground continuous wall and the annular girder.

Means for Solving the Problems The first invention of the present invention is to construct an annular girder in an underground continuous wall by constructing the underground continuous wall in a ring shape, and then excavating the inside of the underground continuous wall. Then, arc-shaped unit precast girders are placed along the inner wall of the diaphragm wall,
A flat jack is interposed on the end face of the unit precast girder, pressure is applied to the unit precast girder by the flat jack, and non-shrink grout is filled into the gap between the unit precast girders to integrate the unit precast girder and the underground continuous wall. become

The second invention is similar to the first invention, in which an underground continuous wall is constructed in a ring shape, the inside of the underground continuous wall is excavated, and arc-shaped units are formed along the inner wall of the underground continuous wall. After placing the precast girder, a tension material whose base end is fixed to the underground continuous wall is protruded between the end faces of the unit precast girder, and a wedge is inserted using the tension material to apply pressure to the unit precast girder. This is a construction method that integrates annular unit precast girders and underground continuous walls.

Embodiment FIG. 1 shows an embodiment of the first invention, in which the underground continuous wall A is constructed by inserting a reinforcing bar cage into an annular excavated trench in the ground and pouring concrete.

Next, the ground inside the underground continuous wall A is excavated, and the required number of arc-shaped reinforced concrete or steel unit precast girders 1 are arranged in a ring shape along the inner wall to the underground continuous wall A, and the unit precast girders are A flat jack 2 is interposed between the end faces of the unit precast girders 1, and the flat jack 2 applies pressure to the unit precast girder 1, that is, introduces prestress, and then non-shrink grouting material 3 is applied to the gap between the unit precast girders 1. The unit precast girder l which is filled to form an annular shape and the underground continuous wall A are integrated.

The above construction will be repeated as required as the ground is excavated.

Fig. 2 shows an embodiment of the second invention, in which an underground continuous wall A is similarly constructed, the inside thereof is excavated, unit precast girders 1 are placed, and then the end faces of the unit precast girders 1 are , the PC whose base end is fixed in the underground continuous wall A
A tension material 4 such as A material is provided protrudingly, and this tension material 4 is used as a reaction force receiver, and a wedge 5 is inserted around it to apply prestress pressure to the unit precast girder, thereby creating an annular unit prestress. This is a construction method that integrates girder 1 and the underground continuous wall.

FIG. 3 shows a case where the present invention is implemented in a shield shaft, and the reference numeral 6 indicates a shield starting part.

Figure 4 shows the case where this invention is implemented in a final waste treatment plant, and the symbol ? , 8 indicates waste and waste pipes.

Effects of the Invention This invention has the above-described configuration, the underground continuous wall and the annular girder are integrated, and prestress is introduced into the annular girder, so that even if the wall thickness is relatively small, the underground continuous wall is reinforced and the continuous wall is sufficiently It can provide high durability.

Moreover, quick construction is possible by using prestressed girders, flat jacks, or wedges.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views showing embodiments of the present invention, and FIGS. 3 and 4 are longitudinal cross-sectional views showing applied examples of the present invention. A... Underground continuous wall, 1... Prestressed girder, 2...
・Flat jack, 3... Non-shrink grout material, 4.
...Tension material, 5...wedge.

Claims (2)

[Claims] (1) Construct an underground continuous wall in a ring shape, then excavate the inside of the underground continuous wall, then arrange an arc-shaped unit precast girder along the inner wall of the underground continuous wall, and place the unit precast girder end face A feature is that a flat jack is interposed between the unit precast girders, pressure is applied to the unit precast girder by the flat jack, and non-shrinkage grout is filled into the gap between the unit precast girders to integrate the unit precast girder and the diaphragm wall. Construction method for circular girders in underground continuous walls. (2) Construct an underground continuous wall in a ring shape, then excavate the inside of the underground continuous wall, then arrange an arc-shaped unit precast girder along the inner wall of the underground continuous wall, and A tension material whose base end is fixed to the underground continuous wall is protruded between, and by inserting a wedge using the tension material, pressure is applied to the unit precast girder, and the unit precast girder and the underground continuity wall are installed. A construction method for annular girders in underground continuous walls, which is characterized by integrating the girder with the wall.