JP2007002522A - Earth reinforcement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an earth reinforcement method capable of using inexpensive materials without causing the differential settlement of an upper structure or its overturning caused by a horizontal force. <P>SOLUTION: In a system of the earth reinforcement method, a solidifying agent is injected and agitated to construct soil cement columns as excavating earth, core materials are inserted in the soil cement column and solidified. The core materials are of wood or bamboo materials. In the case that one core material is used, the interval between the bottom surface of the core material and the bottom surface of the soil cement is equal to its diameter or greater. In the case that a plurality of core materials are used, the interval between the bottom surfaces of the core materials and the bottom surface of the soil cement is equal to the diameter of their circumscribed circle or greater. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ground reinforcement method for supporting a structure, and in particular, by mixing cement milk and other hardeners while excavating the ground and integrating it with a reinforcing core material, the earth bearing strength under the pillar of the structure. It is related with the ground reinforcement method which strengthens.

2. Description of the Related Art Conventionally, various ground reinforcement methods are known in which cement milk is poured into the ground, stirred, and cured together with a core material.
For example, in the invention disclosed in Patent Document 1, an inverted trapezoid taper soil cement column is formed, and a steel pipe pile or an H-shaped steel material as a core material is inserted therein, and the soil cement and the core material are integrated. The combination is described. In such a construction method, one core body is inserted into one soil cement pillar and integrated with the core body. Since the core body is a straight pile, the core body and the ground are Only the frictional force is increased.

  In addition, since it is constructed using an expansion / contraction excavation head when creating a tapered taper soil cement column, considerable subtle control is required to obtain a predetermined cross section at a predetermined position, and it takes time and is not efficient. . Furthermore, in order to improve the inverted frustoconical shape portion as shown in the same document with soil cement, it is necessary to create a considerably large volume, and the amount of cement used increases and the cost becomes high.

On the other hand, the invention of Patent Document 2 has a structure in which a plurality of spiral or disk-shaped steel blades are attached to a concrete pile, and are inserted into a soil cement pillar body to be integrated. It expresses a large frictional force between them.
According to such an invention, since a plurality of steel spiral or disk-shaped blades are attached after the manufacture of the concrete piles, there is a disadvantage that the processing and attaching work are complicated and the cost is high. In addition, since the blades are fixed to the concrete pile, there is a difficulty that sufficient consideration is necessary for transportation and handling at the construction site.
JP 2001-98542 A JP 2001-303563 A

  The present invention provides a ground reinforcement method that solves the above-mentioned problems of the prior art, prevents the upper structure from undue subsidence, does not fall down due to horizontal force, and can use inexpensive materials. There is a soil cement pillar, and one or several pieces of wood or bamboo are inserted and integrated therein as a core material, and the lower end surface of the core material is formed by a part of the soil cement pillar. The present invention provides a method for reinforcing a ground of a supporting type.

The present invention is a ground reinforcing method of a type in which a solidifying agent is injected and stirred while excavating the ground to form a soil cement pillar, and a core material is inserted into the soil cement pillar and solidified. It is made of wood or bamboo. The core material is one or a plurality of woods, which may be connected or bundled in the middle of the longitudinal direction. The core material may be a combination of a plurality of woods or bamboos arranged in an annular shape.
Further, in the ground reinforcement method of the present invention, the distance between the bottom surface of the core material and the bottom surface of the soil cement is equal to or more than the diameter of the core material when it is one, and the circumscribed circle when the core material is plural. It is a ground reinforcement method characterized by having a diameter or more.

According to the present invention, the ground reinforcing means can arbitrarily determine the diameter and depth of the soil cement column corresponding to each column load to be supported, and the number of core materials to be inserted into the soil cement column can also be arbitrarily determined. Can be determined.
In addition, by lifting the edge of the core material from the bottom surface of the soil cement column, it is easy to reduce the load per unit area that acts on the ground from the bottom surface of the core material to less than the strength of the ground material. Along with the resistance caused by the surface friction force, a large supporting force can be obtained.
In addition, it can respond to cedar logging as a countermeasure against cedar pollinosis, which is currently a problem nationwide, and by using relatively inexpensive cedar and bamboo as the core material, it is also environmentally friendly ground reinforcement. The method can provide a special effect such as providing a method.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a plane and a longitudinal section of a structure 1 in a form in which a single core material 3 and a soil cement column 2 are integrated and applied to a necessary portion of the ground G. Such a reinforcing structure 1 for ground reinforcement is constructed using an auger excavator as shown in FIG. 9, for example. First, a necessary portion of the ground G is provided by a drill bit 11 provided on a drill shaft 10 of the auger. Is excavated.
At the same time, while a hardener such as cement milk is injected from the excavation bit 11 portion, the stirring is repeated by the stirring blade 12 to proceed with construction, and the soil cement pillar 2 is formed.

And while the soil cement pillar 2 is uncured, the core material 3 having various structures shown later is inserted and integrated while being pressed or rotated.
The size of the soil cement column 2 is determined by the material and arrangement structure of the core material 3 as well as the column load of the building to be supported and the inherent ground strength of the ground.
What is important here is that the distance L between the bottom surface of the soil cement column 2 and the bottom surface of the core material 3 is equal to or greater than the diameter D of the core material 3.

Hereinafter, FIG. 2 to FIG. 7 show the reinforcing structure 1 having various arrangements or structures of the core material 3.
FIG. 2 shows a plane and a longitudinal section of a structure having three core members 3A to 3C in the structure 1 constructed by the same method as in FIG. That is, the soil cement pillar 2 by an auger is formed like the thing of FIG. 1, The three core materials 3A-3C are inserted in it, and it is solidified simultaneously. In this case, the three core members 3A to 3C are arranged on a circumference having the center of the soil cement column 2 as much as possible.

  FIG. 3 shows an embodiment of a structure in which, for example, a large number of wood or bamboo materials are bundled as the core material 3. That is, a large number of wood or bamboo materials are bundled together with a wire or the like. Such binding means 5 to 5 are performed at appropriate positions, and the core material 3 thus configured is integrated by being inserted into the center portion of the soil cement pillar 2 as in the case of FIG. Is.

4 and 5 show an example in which one piece of wood is used as the core material 3.
In the case of FIG. 4, it inserts and solidifies in the soil cement pillar 2 so that the main port 3a of the wood which is the core material 3 is upward and the end port 3b is downward.
Further, in FIG. 5, the same wood end 3b is inserted and solidified in the soil cement column 2 so that the original port 3a is downward.

  FIG. 6 shows an example in which a large number of woods 3 </ b> A to 3 </ b> N are annularly inserted and integrated as the core material 3. And if the diameter of the circumscribed circle of these timbers 3A to 3N is D, the relationship between the distance L between the lower end surface of the core material 3 and the lower surface of the soil cement column 2 is the same. Is equal to or greater than

  7 and 8 show an example of a structure in which woods as the core material 3 are joined together and an example of the joining structure. The number of timbers in this case is the same as in FIG. 2, but the number is not limited to three. Each timber 3A to 3C is formed by connecting relatively short timbers at arbitrary positions. ing.

FIG. 8 shows an example of the joining means. The upper core material (one piece of wood) 3X and the lower core member (also one piece of wood) 3Y are connected by the fastening band 6, and the scabs 7-7 are connected. These bands and the core materials 3X and 3Y are fixed to form core materials 3A to 3C having a required length.
In this case as well, the relationship between the diameter D of the circumscribed circle of the core material 3 and the interval L between the bottom surfaces of the core material 3 and the soil cement column 2 is as described above.

Explaining the operation in the reinforcing structure according to the present invention, when the weight of the structure to be supported acts on the structure 1 via the pillar, the force is dispersed not only in the core material 3 but also in the soil cement pillar 2, By lifting the bottom surface of the core material from the bottom surface of the soil cement column 2, the force on the bottom surface of the core material can be dispersed.
Therefore, the total supporting force of the peripheral surface friction and the supporting force of the bottom surface of the soil cement column 2 is expressed as a whole, and a strong ground reinforcement is realized.

It is the top and sectional view of the reinforcement structure concerning the 1st example of the present invention. It is the top view and sectional drawing of a reinforcement structure concerning the 2nd example of the present invention. It is the top view and sectional drawing of the reinforcement structure which concerns on the Example which used many wood or bamboo materials collectively as a core material. It is sectional drawing of the reinforcement structure which concerns on the Example using one wood as a core material. It is sectional drawing of the reinforcement structure which concerns on the Example using one wood as a core material. It is a top view and a sectional view of a reinforcement structure concerning the 3rd example of the present invention. It is the top view and sectional drawing of the reinforcement structure which concern on the Example comprised by connecting the core material. It is explanatory drawing of the connection means of core materials. It is creation explanatory drawing of a soil cement pillar.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reinforcement structure 2 Soil cement pillar 3 Core material 5 Bundling means 6 Tightening band 7 Kasugai

Claims (6)

It is a ground reinforcement method in which a solidifying agent is injected and stirred while excavating the ground to form a soil cement pillar, and a core material is inserted into the soil cement pillar and solidified. The core material is made of wood or bamboo. A ground reinforcement method characterized by being. 2. The ground reinforcement method according to claim 1, wherein the core material is one or a plurality of timbers. The ground reinforcement method according to claim 1 or 2, wherein the core members are joined together in the longitudinal direction. 2. The ground reinforcement method according to claim 1, wherein the core material is a bundle of wood or bamboo. 3. The ground reinforcement method according to claim 2, wherein the core material is formed by inserting a plurality of wood or bamboo materials in an annular arrangement. The ground reinforcing method according to any one of claims 1 to 5, wherein the interval between the bottom surface of the core material and the bottom surface of the soil cement is equal to or more than the diameter of the core material when the core material is one. A ground reinforcement method characterized in that, when there are a plurality of pieces, the diameter is equal to or larger than the diameter of the circumscribed circle.

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