JP3147437B2 - Construction method of underground diaphragm wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground continuous wall by constructing a plurality of preceding elements (walls) in the ground and constructing a succeeding element integrally with the preceding elements between the preceding elements. The present invention relates to a method for constructing an underground continuous wall for constructing a wall.

[0002]

2. Description of the Related Art In general, underground continuous walls are constructed as earth retaining walls or foundations of structures, but the following methods are known as methods relatively widely practiced today. Have been.

[0003] First, a plurality of preceding elements (walls) constituting a part of an underground continuous wall are constructed in the ground so as to be separated from each other by the length of substantially one element. These antecedent elements are constructed by first drilling a well, building a reinforced cage into the well and then casting concrete. When the preceding element can be constructed, the vertical hole for the succeeding element is excavated by excavating between two adjacent left and right preceding elements.

[0004] In parallel with the excavation of the vertical hole, the end face in the joining direction of the preceding element is cut and removed by a predetermined size (usually about 10 cm on one end face).

The reason why the end face of the preceding element is cut off is to remove slime adhering to the end face and so-called roughening of the joint face. Then, like the preceding element, a reinforcing bar is erected in the vertical hole for the succeeding element, and concrete is cast to construct the succeeding element integrally with the preceding element and the entire underground continuous wall is constructed. It is to be constructed.

[0006]

In the above-mentioned conventional method, when excavating a vertical hole for a succeeding element between two adjacent left and right preceding elements, the excavator is moved between the two right and left preceding elements. Just set in the middle,
The end face of the preceding element is cut in parallel with the excavation of the vertical hole for the succeeding element. However, since the preceding element is made of concrete, especially in the initial stage of excavation, that is, at the upper end surface of the left and right preceding elements, the excavator is used. When a drill is used to start drilling and cutting of the end face of the element, the drill of the excavator does not bite into the hard concrete so that a so-called escape occurs. For this reason, not only is it not possible to secure a correct cutting line due to displacement, but also there are many cases in which the stability of the excavator is lost and an eccentric load is caused.

The present invention has been proposed in order to solve the above-mentioned conventional problems. When excavating a vertical hole for a succeeding element between two adjacent left and right preceding elements, the present invention has been proposed. Positioning and stable holding can be ensured,
Accordingly, it is an object of the present invention to provide a method of constructing an underground continuous wall that enables stable excavation while maintaining an accurate cutting line.

[0008]

As a means for solving the above problems, a method of constructing an underground continuous wall according to the present invention is to excavate a vertical hole for a preceding element and cast concrete into the vertical hole. The preceding elements are constructed at regular intervals, and then a vertical hole for the succeeding element is excavated between adjacent preceding elements while cutting the end face in the joining direction of the preceding element. In a method of constructing an underground continuous wall by casting concrete inside and constructing a subsequent element that is integral with the preceding element and constructing an underground continuous wall, the concrete joining direction in the vertical hole for the preceding element is Reinforcing cages having partition members at both upper ends are erected, and concrete is poured into the vertical hole for the preceding element up to the lower end of the partition member. A space outside the lever member is filled with gravel or crushed stone, and concrete is cast inside the partition member to construct a leading element, and then a vertical hole for a succeeding element is provided between adjacent preceding elements. The excavator, the left and right partition members with cutting line
While excavating with the gravel or crushed stone, and then laying a reinforcing cage in the vertical hole for the succeeding element and placing concrete, thereby embedding the partition member in concrete and leading element Construct a follow-up element with

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for constructing an underground continuous wall according to the present invention will be described below with reference to FIGS.

First, a vertical hole 1 for a preceding element is excavated. The required number of vertical holes 1 is excavated while securing an interval of approximately one element.

Subsequently, a reinforcing cage 2 is built in each vertical hole 1 for the preceding element (see FIG. 1). Reinforcing basket 2
Is assembled by arranging a required amount of reinforcing bars vertically and horizontally according to the scale of the underground continuous wall to be constructed, and a partition member 3 made of an iron plate or the like is attached to both ends of the upper part in the width direction ( See Figures 7, 8, and 9).

For example, when an iron plate is used, the partition member 3 has a thickness of about 6 to 12 mm, a length of about 3 to 4 m, and a width substantially equal to the width of the vertical hole 1 for the preceding element. It is used. The partition member 3 is buried in the concrete and killed.

Subsequently, concrete 4 is placed in the vertical hole 1.
(See FIG. 1). For placing concrete 4,
The tremy tube 5 is used so that concrete can be prevented from separating and dense concrete can be obtained. still,
The tremy tube 5 is removed immediately after the concrete is poured.

When the concrete 4 reaches the lower end of the partition member 3, the space portion 6 outside the left and right partition member 3 is filled with an easily excavated material such as gravel or crushed stone 7 to the ground surface while the right and left partition members 3, 3 are being filled. Concrete 4 is continuously poured into the ground only to the inside of the ground (see FIG. 2). In this way, the individual preceding elements 8 are constructed (see FIG. 3).

In this case, the adjacent left and right preceding elements 8,
Distance L ₁ between the partition member 3,3 8 slightly with larger than the width W of the vertical hole 9 for the trailing element (excavation width of the excavator) (about 10 to 50 mm), also lateral preceding elements 8,8 distance L ₂ between the partition member 3 of the right and left preceding elements 8,8,
Than the distance L ₁ between 3 about twice (about 220 to 300 mm) of the width S of the left and right space portions 6 only to narrow (see FIGS. 4 and 5).

When the construction of each preceding element 8 is completed, the excavator is located at the center between the two right and left preceding elements 8
10 is installed, and excavation of the vertical hole 9 for the succeeding element is started (see FIG. 5).

In the initial stage of the excavation of the vertical hole 9, it is not necessary to cut the left and right preceding elements 8 and 8, and the excavation of the gravel or crushed stone 6 that is easy to excavate is performed smoothly to the lower end of the partition member 3. After that,
The original excavation is performed while cutting the left and right preceding elements 8, 8 end faces.

In such a case, the interval L ₁ between the partition members 3 of the left and right preceding elements 8 is equal to the width W (L ₁ >) of the vertical hole 9.
L ₂₎ and for substantially made equal, even if the cutting of the preceding element 8 is started, without causing any positional deviation, it is possible to ensure proper cutting line.

In the initial stage excavation up to the lower end of the partition member, for example, a backhoe, a clamshell or the like other than the excavator 10 may be used, and the excavator 10 may be used for subsequent excavation.

When the excavation of the vertical hole 9 is completed, similarly to the case of the preceding element 8, a reinforcing bar (not shown) is erected in the vertical hole 9, and concrete 4 is cast, so that the succeeding element 11 is replaced with the preceding element 8. (See FIG. 6). The following element 11 is intended to shorten the construction period by performing the operation at a plurality of locations in parallel.

FIG. 10 shows a case where a curved underground continuous wall such as a cylindrical underground structure is constructed. In such a case, the left and right partition members 3, 3 of the preceding element 8
Is obliquely attached to the end of the reinforcing steel cage 2 in accordance with the curvature of the underground continuous wall to be constructed, so as to correspond to the curvature of the underground continuous wall to be constructed.

[0022]

Since the present invention is configured as described above, it has the following effects.

When a vertical hole for a succeeding element is excavated between adjacent left and right preceding elements by an excavator, excavation at an initial stage in which the position of the excavator is determined does not involve cutting of the preceding element and is easy to cut. In order to excavate rocks and crushed stones, the excavation of the succeeding element in the initial stage can be performed extremely smoothly.

Further, since the positioning and posture of the excavator in the initial stage are surely maintained by the left and right partition members,
Excavation can be stably performed while preventing the excavator from escaping and maintaining an accurate excavation line.

Further, in the space outside the partition member,
In order to fill in irregular members such as gravel and crushed stones instead of installing fixed members such as spacer boxes, the shape of the joint between the preceding element and the succeeding element can be changed freely, so let's build The underground continuous wall having an arbitrary curved surface shape can be easily constructed by giving an arbitrary curvature to the underground continuous wall.

[Brief description of the drawings]

FIG. 1 is a front view of a preceding element at the beginning of construction showing a construction method of the present invention.

FIG. 2 is a front view of the preceding element immediately before the completion of construction, showing the construction method of the present invention.

FIG. 3 is a front view of a preceding element constructed by the construction method of the present invention.

FIG. 4 is a front view of adjacent left and right preceding elements constructed by the construction method of the present invention.

FIG. 5 is a front view showing a construction method of the present invention when excavating a vertical hole for a succeeding element.

FIG. 6 is a front view of a leading element and a trailing element constructed by the construction method of the present invention.

FIG. 7 is a front view of a reinforcing cage used in the construction method of the present invention.

FIG. 8 is a plan view of the reinforcing cage shown in FIG. 7;

FIG. 9 is a plan view showing an installation state of a reinforcing cage.

FIG. 10 is a plan view of a preceding element showing another construction method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vertical hole for preceding element, 2 ... Reinforcing cage, 3 ... Partition member, 4 ... Concrete, 5 ... Tremy tube, 6 ... Space, 7 ... Gravel and crushed stone, 8 ... Leading element, 9 ... For trailing element Vertical hole, 10 ... excavator, 11 ... trailing element.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukiki Miyoshi 1-3-8 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. Tokyo Branch (72) Inventor Shinichi Nagase 1-2-2 Moto-Akasaka, Minato-ku, Tokyo No. 7 Kashima Construction Co., Ltd. (72) Inventor Kazuo Suzuki Kashima Construction Co., Ltd. 1-2-7 Moto-Akasaka, Minato-ku, Tokyo

Claims (1)

(57) [Claims] 1. A vertical hole for a preceding element is excavated, concrete is poured into the vertical hole to construct a preceding element at regular intervals, and then a vertical hole for a succeeding element is formed between adjacent preceding elements. Excavating while cutting the end face of the preceding element in the splicing direction, placing concrete in the vertical hole for this succeeding element and constructing the following element that is integral with the preceding element to construct an underground continuous wall In the method for constructing an underground continuous wall, in a vertical hole for the preceding element, a reinforcing steel cage having partition members at both upper ends in the concrete splicing direction is erected, and then the partition member is inserted into the vertical hole for the preceding element. Concrete is poured to the lower end, and then the space outside the partition member is filled with gravel or crushed stone, and concrete is filled inside the partition member. A leading hole for the following element between the adjacent preceding elements by an excavator,
By excavating with the gravel or crushed stone while holding the cutting line , and then laying a reinforcing cage in the vertical hole for the succeeding element and placing concrete, the partition member is buried in concrete and A method for constructing an underground continuous wall, comprising constructing a trailing element integral with a preceding element.