JPH0357246B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method of constructing an underground continuous wall constructed by forming elements (walls) underground and connecting these elements.

``Prior art'' Underground continuous walls constitute earth retaining walls, ice-stopping walls, foundations of structures, underground structures, etc., and the commonly used construction methods are described below. There is something.

First, two preceding elements (wall bodies) constituting a part of the continuous wall are formed in the ground, separated from each other by approximately the length of one element. These preceding elements are constructed by constructing an excavated hole for forming the preceding element, then erecting a reinforcing cage in the excavated hole, and pouring concrete therein. Once the preceding elements have been constructed, a hole for the succeeding element is constructed by excavating between the two preceding elements. However, at the same time as this excavation, the preceding element
The end face facing the drilling hole for the trailing element is cut and removed to a predetermined size (usually around 10 cm). This is to remove slime adhering to this end face and to roughen the so-called joint surface. After that, a reinforcing cage is erected in the excavated hole for the trailing element and concrete is poured to form the trailing element, and by connecting the preceding element and the trailing element, a continuous wall is created underground. forming,
That is what it is.

``Problems to be Solved by the Invention'' By the way, in the conventional construction method described above, when constructing an excavated hole for the following element between the two preceding elements, the excavator is moved to the intermediate position between the two preceding elements. This is intended to cut the end face of the preceding element in the pouring direction to a predetermined dimension at the same time by positioning it at the top and digging downward, but since the preceding element is made of concrete, it is difficult to cut the end face of the preceding element in the pouring direction at the same time. When the drilling drill of the excavator engages the upper end of the two preceding elements and is about to start digging and cutting the end face of the element, the excavator does not bite into the hard concrete smoothly and the so-called escape occurs. It will happen. For this reason, there was a risk that not only would the position shift occur, making it impossible to ensure a correct cutting line, but also that the stability of the excavator would be compromised, leading to uneven loads.

The present invention was made in view of the above circumstances, and
When forming an excavation hole for the trailing element while cutting the end face of the leading element between the two leading elements, the underground continuous wall allows for smooth positioning of the excavator and thereby achieves stable excavation. The purpose is to provide a method for constructing a .

"Means for solving the problem" The present invention divides the underground continuous wall to be constructed into a plurality of elements in the construction direction, and forms excavated holes for forming the preceding elements at regular intervals in advance. After pouring concrete into the excavated hole to form a leading element, an excavator is used to excavate between these leading elements, and at the same time, the end face of the leading element in the pouring direction is cut to a dimension l to form a hole for the trailing element. In a method for constructing a continuous underground wall, in which a continuous wall is constructed by excavating a hole and pouring concrete into the excavated hole to form a subsequent element that is continuous with the preceding element, A step of pouring concrete with a spacer box having a thickness of l interposed in at least the upper end of the excavation end face in the pouring direction of the excavation hole to form a preceding element, and removing the spacer box after the concrete hardens to form the preceding element. The present invention is characterized by comprising a step of forming a wide spaced portion having a large end face distance therebetween, and a step of excavating between the two preceding elements using the wide spaced portion as a guide for the excavator.

"Operation" At the initial stage of drilling between the preceding elements, the positioning and stabilization of the excavator can be ensured, thereby ensuring an accurate drilling line.

"Embodiments" Examples of the present invention will be described below with reference to FIGS. 1 to 7.

First, as shown in FIG. 1, a drilling hole 1 for the preceding element is drilled. The depth and width (wall thickness) of this excavated hole 1 are the same as the dimensions of the intended continuous wall.
The length (width in the direction of joining) shall be several meters. Once the excavated hole 1 for the preceding element has been constructed, the reinforcing bar cage 2 is erected in this excavated hole 1, and then
Concrete 4 is poured using a tremie pipe 3, and at this time, a spacer box 5 is attached in advance to the upper part of the excavated wall surface 1a in the pouring direction of the excavated hole 1. The spacer box 5 is in the form of a plate, as shown in FIG. 4, and in the embodiment, the width is approximately equal to the excavated wall surface 1a, and the thickness is such that it cuts the end face of the preceding element in the joining direction, which will be described later. It is approximately equal to the actual cutting dimension l (approximately 10 cm in the example),
It is approximately 5 meters long. Further, this spacer box 5 is provided with a fixing head 5a at its upper end so that it is attached to the excavated hole 1 and does not come off.

The poured concrete 4 hardens and becomes the second concrete.
Once the leading element 6 has been formed as shown in the figure, the spacer box 5 is pulled out and removed. As a result, a space 7 equal to the thickness of the spacer box 5 is formed in the upper part of the leading element 6 at both ends in its width direction, as shown in FIG.

Once the preceding element 6 as described above is formed, as shown in FIG. 5a, similar preceding elements 6 are formed at a predetermined distance from the preceding element 6 by the same procedure as described above. The spacing provided between the two preceding elements at this time is as follows. This is related to the subsequent element described later. That is, a trailing element is formed between the two leading elements 6, and for this purpose, an excavated hole 8 for the trailing element is constructed between the leading elements 6, as shown in FIG. 5b. At the same time as this excavation, the end faces 6a of the preceding elements 6 on both sides in the pouring direction are cut and removed by a required size, and if this cutting size is l,
The distance A between the two preceding elements 6 is set to be 2l shorter than the width B excavated by an excavator (described later). Since the two leading elements 6 thus formed form the space 7 in their respective upper parts, the concrete portion forming the leading elements 6 is a wide-spaced part in which the distance between the mutual end faces is large in the upper part. 9.

Next, as shown in FIG. 6, in order to form a trailing element, an excavator 10 is installed at the center between these leading elements and excavation is started from the upper part thereof. At this time, cutting of the splicing end surfaces 6a of these preceding elements 6 is not performed in the initial stage of this excavation. This is because the distance between the wide space portions 9 is approximately equal to the width of the excavator 10. As a result, positioning can be performed smoothly without causing so-called escape of the cutting edge, which occurs when the excavator does not bite into hard concrete. In addition, the wide spaced portion 9, which is approximately the same width as the excavator 10, serves as a guide when the excavator 10 excavates downward, thereby allowing the excavator 10 to maintain a vertical posture and perform stable excavation. Without,
Even when cutting and removing the end face 6a of the preceding element in the splicing direction, it is possible to ensure an accurate cutting line, that is, to reliably cut the required l dimensions evenly.

Drilling hole 8 for trailing element by excavator 10
Once formed, a reinforcing cage is installed in the excavated hole 8 by conventional means, and then concrete is poured to form the trailing element 11 that connects to the leading element. Thereafter, the following elements 11 may be formed between the preceding elements 6, which are formed intermittently, in the same manner as described above, to complete the underground continuous wall W.

FIG. 8 shows another embodiment of the present invention, in which a cylindrical structure 12 is formed by an underground continuous wall W.
The figure shows the case where a building is constructed. Cylindrical structure 12
In order to make the shape as close to a perfect cylinder as possible, when constructing it using so-called rectangular bodies such as elements, it is necessary to increase the number of polygons as much as possible. It is desirable to set an angle to That is,
When forming the trailing element 11 on the leading element 6, an angle is also formed between them.

Now, FIG. 8 shows two leading elements 6 formed at a predetermined distance and at a predetermined angle. These preceding elements 6
During this time, the drilling hole 8 for the trailing element is excavated while cutting the end face 6a of the preceding element in the splicing direction, but at this time, since the end faces 6a of the two preceding elements 6 in the splicing direction are not parallel. The dimensions of the cut-out portion 13 differ between the inside and outside of the continuous wall W. In other words, the cross section is cut and removed in a substantially trapezoidal shape. Therefore, in such a case, when forming the preceding element 6, a spacer box 5 having substantially the same cross-sectional shape as the cut-out portion 13 is used as the spacer box 5 shown in the first embodiment. By doing so, when the two leading elements 6 are formed and the spacer box 5 is removed, the joining surfaces 6b forming the wide spaced portion 9 can be parallel. Therefore, similarly to the first embodiment, the excavator 10 (not shown in FIG. 8) does not start cutting the cut-and-remove portion 13 from the initial stage of excavation, but uses the wide-spaced portion 9 as a guide. Stable excavation can be performed.

In the example, the length of the spacer box is approximately 5 m, but the length of the spacer box is not limited to this, and is long enough to sufficiently stabilize the excavator 10 (depth )
Any material having a length that forms the wide-spaced portion 9 may be used.

"Effects of the Invention" As explained above, the present invention divides the underground continuous wall to be constructed into a plurality of elements in the construction direction, and forms excavated holes for forming the preceding elements at regular intervals in advance. After pouring concrete into the excavated hole to form a leading element, an excavator is used to excavate between these leading elements, and at the same time, the end face of the leading element in the pouring direction is cut to a dimension l to form a hole for the trailing element. In a method for constructing a continuous underground wall, in which a continuous wall is constructed by excavating a hole and pouring concrete into the excavated hole to form a subsequent element that is continuous with the preceding element, A step of pouring concrete with a spacer box having a thickness of l interposed in at least the upper end of the excavation end face in the pouring direction of the excavation hole to form a preceding element, and removing the spacer box after the concrete hardens to form the preceding element. The method includes a step of forming a wide spaced part having a large end face distance between the two preceding elements, and a step of excavating between the two preceding elements using the wide spaced part as a guide for the excavator. When starting excavation between the preceding elements to construct an excavation hole for the succeeding element, positioning is performed smoothly in the initial stage without causing the so-called escape phenomenon in which the excavator avoids hard concrete. Moreover, by using it as a guide for an excavator in a wide space area, it is not only possible to hold the excavator in a vertical position and perform stable excavation, but also to accurately cut and remove the end face of the leading element in the pouring direction. It has excellent effects such as making it possible to secure the cutting line.

[Brief explanation of drawings]

FIGS. 1 to 7 illustrate one embodiment of the present invention, and FIGS. 1 to 3, FIGS.
Fig. 7 is a side sectional view explaining the construction procedure of the underground continuous wall, Fig. 4a is a side view of the spacer box, Fig. 4b is a front view of the spacer box,
FIG. 5b is a top view of FIG. 5a. FIG. 8 explains another embodiment of the present invention, and is a top view showing a part of the construction pattern of the cylindrical structure 12. 1... Excavation hole for the preceding element, 4... Concrete, 5... Spacer box, 6... Preceding element, 6a... End face in pouring direction, 7... Space, 8... Excavation hole for the following element , 9... wide interval part, 10... excavator, 11... trailing element, 13... cutting and removal part, W... underground continuous wall.

Claims (1)

[Claims] 1 Divide the underground continuous wall to be constructed into a plurality of elements in the construction direction, drill holes for forming the preceding elements at regular intervals in advance, pour concrete into the excavated holes, and form the preceding elements. After forming, use an excavator to excavate the space between these preceding elements, and at the same time cut the end face of the preceding element in the pouring direction to a dimension l to excavate a hole for the succeeding element, and pour concrete into this excavated hole. In the method for constructing a continuous wall by forming a succeeding element continuous with the preceding element, at least the upper end of the cut end face in the pouring direction of the excavated hole for forming the preceding element. A process of pouring concrete with a spacer box having a thickness of l dimension interposed between the concrete and forming the preceding element, and removing the spacer box after the concrete hardens to form a wide spaced part between the preceding elements with a large distance between their end faces. and a step of excavating between two preceding elements using the wide spaced portion as a guide for the excavator.