JPS63304819A - Construction method of continuous underground wall - Google Patents

Abstract

PURPOSE:To make it possible to construct a curved continuous underground wall by forming a form into a right angled triangle section and setting so as the end of a construction joint in the preceding panel is at right angles to an axis of the succeeding excavated trench in the case of drawing the form. CONSTITUTION:Both sides of the preceding excavated trench 10 are partitioned into trapezoids by inserting a hollow form 12 having a right angled triangle section, which size is correspondent to that of the width of the trench, into the construction joint section. Then, an area enclosed by the hollow form 12 in the preceding excavated trench 10 is filled with concrete, and start to solidify. And, it is set so as to cross at right angles with the center axis l2 of the succeeding excavated trench 16. According to the constitution, a jointing of successive pours between the preceding panel and the succeeding panel is executed smoothly without making unbalance of excavation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a construction method for a continuous underground wall having an approximate curved shape, which is applied to a circular earth retaining wall or the like.

(Prior Art) When constructing a continuous underground wall, there are two methods: the interlocking pipe method and the cudding joint method, in which a trailing panel is joined to a leading panel.

In the former interlocking pipe construction method, locking pipes are inserted at both ends of a pair of preceding sections, concrete is poured in the sections separated by each locking pipe, the preceding panels are built, and then the locking pipes are pulled out and the subsequent sections are separated. This method involves excavating the area and installing subsequent panels.

In addition, in the latter cutting joint construction method, the joint surface of the rectangular parallelepiped leading panel formed in the preceding work section is cut with a hydrocutter etc. when forming the excavation groove for the succeeding work section, and the defective concrete in the joint section is removed. This is a construction method in which weak parts such as walls are removed, concrete is poured, and subsequent panels are poured.

(Problems to be Solved by the Invention) Each of these construction methods has its own merits and demerits, but all of them are effective as construction methods for linear continuous underground walls.

However, when constructing a continuous underground wall with an approximate curved shape horizontally, such as a circular retaining wall, there are the following drawbacks.

That is, in all of these construction methods, the polygonal shape along a predetermined curvature is adapted to the curved surface shape.

In the interlocking pipe construction method, the sixth
As shown in the figure, the front and trailing panels 1.2 are formed along the curvature of a circle on a straight line with a single excavation width corresponding to the diameter of the rocking pipe 3 with the center of the rocking pipe 3 as its intersection point, forming a polygonal shape. However, as the curvature increases, the intersection angle between the leading and trailing panels 1.2 becomes smaller, and the intersection angle between the leading and trailing panels 1.2 after the locking pipe 3 is pulled out. The curved joint surface of the leading panel 1 interferes with the excavator when excavating the trailing excavation trench, making it difficult to excavate to form the trailing panel 2. There was a problem with becoming.

In addition, in the case of a simple combination of a single excavation width in the cutting joint construction method, as shown in FIG. must be cut in the wedge shape shown by the diagonal lines, and the cutting resistance becomes unbalanced between the inside and outside, which tends to reduce excavation ability and accuracy at the joint, especially in deep parts, as shown by the diagonal lines. It was not cut and the construction accuracy was low.

The present invention has been made in view of the above problems, and its purpose is to apply the above-mentioned cutting method when constructing this kind of continuous underground wall with a curved surface shape, and to solve the problems of the cutting method. The present invention provides a method for constructing a continuous underground wall in which there is no unbalance in cutting and a good joint can be made between the leading panel and the trailing panel.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a method for constructing a continuous underground wall in a polygonal shape so as to form an approximate curved surface with a predetermined curvature. Formwork is inserted into the joining part of each of these pre-excavation trenches, and concrete is poured into the section separated by the formwork to form a pair of pre-excavation panels. While excavating the matching leading panels in a straight line, cutting the joint end faces of the preceding panels and pouring concrete into the formed trailing excavation groove, the trailing panels are connected between the leading panels. In a method for constructing a continuous underground wall in which concrete is connected at a predetermined crossing angle;
The formwork is arranged so that the joining part of the preceding panel is partitioned by the oblique side thereof, and the joining part of the preceding panel is perpendicular to the axis of the trailing excavation groove when the formwork is pulled out. The inclination angle of the oblique side portion is set.

(Function) When a trailing excavation groove is excavated by connecting the preceding panels in a straight line, the joint surfaces of the preceding panels are exposed at both ends of the trailing excavation groove in a state perpendicular to the axis of the trailing excavation groove. The cutting surfaces of the two abut against each other in a parallel state, and no imbalance occurs.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings. 1 to 5 show the construction order of this invention.

In FIG. 1, a pair of pre-excavated grooves 10 have appropriate lengths and widths to drain muddy water so that they intersect at a predetermined intersection angle on the extension of the respective central axes j1 along the curved surface to be obtained. Each hole is excavated to a predetermined depth with a rectangular parallelepiped cross section.

Next, as shown in FIG. 2, a hollow formwork 12 having a right triangular cross-section and a dimension corresponding to the groove width is inserted into both ends of each excavated groove 10, that is, the joint part, and the hypotenuse part 12a of this formwork is inserted. Both sides of the preceding excavation groove 10 are partitioned into a trapezoidal shape.

One side 12b of this hollow formwork 12 is equal to the groove width dimension a, and is located in the width direction of the preceding excavated groove 10.

Further, the oblique side 12a is set at an inclination angle perpendicular to the axis of the trailing panel, which will be described later. Therefore, once the intersection angle between the leading panel and the trailing panel is determined, the other side 12c can be adjusted by a simple function ratio. The length is set, and the dimensional relationship of each part of the hollow formwork 12 is determined.

Next, a reinforcing bar cage (not shown) is erected within the section partitioned by the hollow formwork 12, and then concrete is poured using tremie pipes, etc., and the muddy water filling the inside of the excavated trench 10 is poured. Replace.

Through the above operations, the pre-excavated trench 1 is completed as shown in Figure 2.
The area surrounded by the hollow formwork 12 inside 0 is filled with concrete and hardening begins.

From this state, the hollow formwork 12 is pulled out while gradually cutting off the concrete by vibration or the like, and then the concrete is completely solidified to complete the construction of the preceding panel 14 having a trapezoidal cross section as shown in FIG.

After the construction of the preceding panel 14 is completed, the trailing excavation groove 16 is excavated while being filled with muddy water.

As shown by the imaginary line in FIG. 3, this excavated groove 16 is on a line connecting both sides in the width direction between the joining surfaces 14a, which are the end faces of each preceding panel 14, and its central axis 92 is on the line connecting both sides in the width direction between the joining surfaces 14a, which are the end surfaces of each preceding panel 14. It intersects with the central axis 11 at a predetermined crossing angle.

Here, the inclination angle of the oblique side portion t2a of the hollow formwork 12 is set in advance so as to intersect with the central axis j2 of the trailing excavation groove 16 at an angle perpendicular to it, as described above.

Therefore, as shown in FIG. 4, when cutting the joint surface 14a of the preceding panel 14 simultaneously with excavation,
8 hits parallel to the joint surface 14a and cuts the joint surface 14a to a uniform thickness d.

As a result, compared to the conventional case in which the cutter 18 intersects with the joint surface at a certain angle, it is possible to cut with a uniform thickness, and it is possible to cut to the deepest part with high precision.

After the excavation and cutting work is completed, the reinforcing cages are erected and the concrete is placed in the same manner as the preceding panel 14, and the trailing panel 20 is constructed between the leading panels 14 as shown in FIG. , completing the transition.

(Effects) As explained in detail using the embodiments above, in the continuous underground wall construction method according to the present invention, when the preceding panels are connected in a straight line and the trailing excavation trench is excavated, the trailing excavation trench is excavated. Since the joint surface of the preceding panel is exposed at both ends of the excavated groove in a state perpendicular to the axis, the cutter comes into contact with the joint surface in parallel,
Since cutting work is performed, there is no possibility of imbalance.

Therefore, according to the present invention, there is no unbalance in cutting, which is a drawback of the cutting joint construction method, and it is possible to successfully connect the leading panel and the trailing panel.

[Brief explanation of drawings]

Figures 1 to 5 are process explanatory diagrams showing the construction method of a continuous underground wall according to the present invention, Figure 6 is an explanatory diagram showing a construction method using conventional interlocking pipes, and Figure 7 is an explanatory diagram showing the construction method using conventional interlocking pipes. It is an explanatory view showing a construction method using a cutting joint construction method. 10... Advance excavation groove 12... Hollow formwork 12a... Oblique side part 14...
- Leading panel 14a... Connection part 16... Trailing excavation groove 18... Cutter 20... Trailing panel

Claims (1)

[Claims] (1) When constructing a continuous polygonal underground wall with a predetermined curvature and an approximated curved surface, a linear pre-excavated trench is formed along the curved surface, and the joints of each of these pre-excavated trenches are A formwork is inserted into the area, and concrete is poured into the sections partitioned by the formwork to form a pair of preceding panels. Next, adjacent preceding panels are connected in a straight line and excavation is carried out, and the preceding panels are A continuous underground wall construction method in which the joint end faces of panels are cut, concrete is poured into the trailing excavation grooves formed, and the trailing panels are joined at a predetermined crossing angle between the leading panels. ; The formwork is formed in a right triangular cross section according to the groove width,
The formwork is such that the joining surface of the preceding panel is partitioned by the oblique side thereof, and the joining surface of the preceding panel is perpendicular to the axis of the trailing excavation groove when the formwork is pulled out. A continuous underground wall construction method characterized by having a set inclination angle of the hypotenuse.