JP4841899B2 - Construction method of soil cement column wall - Google Patents

Description

  The present invention relates to a method for constructing a soil cement column wall that constructs a soil cement column wall by freely changing the lapping margin of each element.

The soil cement column wall (SMW wall) is an underground wall body built on site. In general, cement milk is poured into the ground while being ground to a predetermined depth using a multi-hole type (multi-shaft) drilling device equipped with a plurality of augers, and stirred and kneaded. It is built by building and hardening a core material made of steel.
Since the soil cement column wall can be constructed much more easily and inexpensively than the underground continuous wall, it has been widely used as a retaining wall or a water blocking wall.

  As shown in FIG. 6, the conventional soil cement column wall is generally constructed by completely wrapping the end of a multiple (multi-axis) type drilling device.

However, the conventional method for constructing a soil cement column wall with a complete wrap has the following problems.
<1> Drilling work at the end portion to be completely wrapped and the filled cement milk are wasted, and the waste soil sludge is increased, so the construction efficiency is remarkably low.

<2> When the core material is built equally, the position of the core material is limited to the center of the drilled hole, so that the degree of freedom of arrangement is limited and the arrangement pitch is also restricted.

  An object of the present invention is to provide a method for constructing a soil cement column wall, which has higher construction efficiency than conventional construction methods and can reduce construction costs while ensuring water-stopping properties.

In order to achieve the above object, the first invention of the present application is to construct a soil cement column wall using a multiple-type drilling device having a plurality of augers and rotating the auger to form a reference element. A method for constructing a soil cement column wall, wherein a distance P2 between one end center of an existing reference element and one end center of a preceding element is a center distance P1 between both ends of the reference element. A process of constructing a preceding element to exceed
The rear end of the trailing element is partially wrapped around the end of the reference element to form a wrap margin, and the other end of the trailing element is partly wrapped to the end of the preceding element to form a wrap margin. A step of constructing a row element, and a step of building a core material in the wrap margin obtained by wrapping a part of the end portion of the reference element and the preceding element, and drilling holes in the end portions of the elements to be wrapped A method for constructing a soil cement column wall is characterized in that a distance d connecting the outer peripheral intersections is larger than a width H of the core material and smaller than a diameter D1 of the drilled hole .

A second invention of the present application provides the method for constructing a soil cement column wall according to the first invention of the present application, wherein the core material is an H-shaped steel .

Lapping each other end in the neighboring Ri fit element is preferably set to 50% of the distance between the centers of the end portions to wrap.

The present invention can obtain at least one of the following effects by means for solving the above-described problems.
<1> Compared with a conventional construction method using a complete lap, the construction pitch between elements is widened, and construction efficiency is improved.
<2> The volume of the wrap portion between elements can be reduced, and the amount of cement milk used can be reduced.
<3> The degree of freedom of the arrangement pitch of the core material is increased, and the number of core material arrangements can be saved.
<4> Generation of discharged sludge due to drilling is reduced, and environmental impact can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The drilling device used in the present invention uses a conventionally known triaxial drilling device, and a structure formed by a single drilling operation is defined as a reference element 2.
FIG. 1 shows a plan view of the reference element 2. The distance between the center points 221 and 231 of both ends 22 and 23 formed by the augers at both ends of the reference element 2 is P1, and the total length of the reference element 2 is L1.
Hereinafter, the steps of the construction method of the present invention will be described with reference to FIG.

<1> Construction of Preceding Element 3 FIG. 2A shows the arrangement relationship between the reference element 2 and the preceding element 3.
The preceding element 3 is constructed with a certain distance apart so as not to wrap to the reference element 2 already formed in the ground.
Specifically, the distance between the center point 221 of the one end 22 of the existing element 2 and the center point 331 of the one end 33 of the preceding element 3 is P2, and the preceding P2 exceeds P1. Build element 3.
However, since the water cannot be stopped unless each element wraps at all, the preceding element 3 must be constructed so that the distance L2 between the reference element 2 and the preceding element 3 does not exceed the total length L1 of the reference element 2. It goes without saying that it doesn't happen.

<2> Construction of the succeeding element 4 FIG. 2B shows the positional relationship between the existing elements and the succeeding elements.
Trailing element 4, build a portion of both end portions of each element so as to wrap between the reference element 2 and the preceding element 3.
Specifically, the drilling device is arranged so that the end portion 43 of the succeeding element 4 is wrapped on the end portion 22 of the reference element 2 and the end portion 42 of the succeeding element 4 is wrapped on the end portion 33 of the preceding element 3. Position and build the trailing element 4.
The size of the lap allowance of the wrap portion 6 varies depending on P2 determined when the preceding element 2 is constructed.

According to the present invention, the core material can be arranged symmetrically from the center of each element, and the core material pitch can be made variable.
For example, as shown in FIG. 3, the distance d connecting the outer peripheries of the drilling holes at the end portions of the elements to be wrapped is made larger than the width H of the core material, so that the cross section of the drilling hole forming the wrapping part 6 has a small constriction. If it makes a gourd shape, the core material 5 can be arrange | positioned in the lap | wrap part of an adjacent element edge part.

For example, when using a drilling device having a drilling diameter of 550 mm and a core material of 450 × 200, it is preferable to set the lap margin of each end of adjacent elements to 50% of the center-to-center distance between the ends. In this case, the distance d which connects the intersection of each element mutually wraps 86.6% of the auger diameter (diameter of the drilling hole) D 1 = approximately 476Mm. The core material 5 generally has a height of about 80% of the auger diameter, and the core material 5 can be built in the lap portion.

  In the conventional construction method using a complete lap, as shown in FIG. 6, the core material was built only in the center of the hole, but according to the present invention, as shown in FIG. The core pitch can be increased from P1 to P2 to the extent that the required water-stopping, workability, strength, etc. required for the soil cement column wall are satisfied, and as a result, the total number of cores used can be reduced. Therefore, the construction cost can be reduced.

In this embodiment, a triaxial drilling device is used, but the same effect can be obtained even when a 5-axis drilling device is used.
The present invention can also be applied to continuous drilling. For example, as shown in FIG. 5, soil cement columns are formed by continuously forming elements while ensuring a certain lapping margin so that the center points of the end portions 22 and 33 of adjacent elements do not coincide (do not completely wrap). A similar effect can be obtained by constructing a row wall.

  As described above, according to the present invention, the construction length of the soil cement column wall in one drilling operation is increased, the construction work period can be greatly shortened, and the volume of the lap portion of each element can be reduced. The waste of drilling again can be reduced. Moreover, the usage-amount of cement milk can also be reduced and it can contribute to the improvement of construction cost and construction efficiency. Moreover, since the amount of sludge discharged in the drilling process is also reduced, the amount of industrial waste treated can be reduced, and the environmental impact can be reduced.

The top view of the reference | standard element of this invention. The figure which shows the process of the construction method of this invention. The enlarged view of the wrap part of each element which concerns on this invention. The top view of the soil cement column wall which concerns on the Example of this invention. The top view of the soil cement column wall which concerns on the other Example of this invention. The top view of the construction method of the conventional soil cement pillar row wall.

DESCRIPTION OF SYMBOLS 1 Soil cement column wall 2 Reference | standard element 21 Center part 22, 23 End part 221, 231 Center point 3 Predecessor element 31 Center part 32, 33 End part 321, 331 Center point 4 Subsequent element 41 Center part 42, 43 End part 421 Center point 5 Core material 6 Wrap part

Claims (2)

A method for constructing a soil cement pillar row wall, comprising a plurality of augers and constructing a soil cement pillar row wall using a multiple-type drilling device that forms a reference element by rotating the auger,
Constructing the preceding element such that a distance P2 between one end center of the existing reference element and one end center of the preceding element exceeds a center-to-center distance P1 between both ends of the reference element;
The rear end of the trailing element is partially wrapped around the end of the reference element to form a wrap margin, and the other end of the trailing element is partly wrapped to the end of the preceding element to form a wrap margin. Building a row element;
Building a core material in the lapping allowance that wraps a part of the end portion of the reference element and the preceding element , and
The distance d connecting the outer peripheral intersections of the drilling holes at the end portions of the elements that overlap each other is larger than the width H of the core material and smaller than the diameter D1 of the drilling holes ,
Construction method of soil cement column wall. The method for constructing a soil cement column wall according to claim 1, wherein the core material is an H-shaped steel .

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