JPH0751771B2 - Ground improvement method for foundation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a ground improvement method for foundation for the purpose of preventing uneven settlement of a lightweight building or destruction of a concrete foundation due to soft ground.

(Prior art) When building a building such as a house on soft ground, the ground is improved in advance by adding a solidifying material to the soft ground,
It prevented uneven settlement of lightweight buildings or destruction of concrete foundations due to soft ground. Then, conventionally, the ground improvement has been performed on the entire site area where the building is built.

(Problems to be Solved by the Invention) Although the ground improved by adding a solidifying material has compressive strength and shear strength, it has no tensile strength at all. Therefore, there is a problem that the ground is cracked at the bend when the ground is unevenly subsided.

In addition, the place where the ground strength is necessary to prevent uneven settlement of the building or the destruction of the concrete foundation is the place where the foundation is placed, and at other positions, it is not necessary to add a solidifying material etc. No improvement needed. Therefore, if the ground is improved over the entire area of the site as before,
There is a problem that a large amount of material such as a solidifying material is required and that the construction cost is high due to the long construction time.

(Means for Solving Problems) The present invention is to excavate only the place where the foundation of the present ground is provided to remove the topsoil, and to disperse an appropriate amount of the solidifying material to the base bottom of the ground from which the topsoil has been removed. After mixing and stirring this solidified material and the base bottom excavated to an appropriate depth, rolling is performed to form the base plate, and reinforcements formed in a grid or mesh form are arranged on the base plate. Then, a new good quality earth and sand is laid on this reinforcing material to an appropriate thickness, and the new earth and sand and the solidifying material are mixed and stirred, and then the material is compacted to form the upper ground and form the foundation ground. It is a ground improvement method for foundations.

(Function) Only the place where the foundation of the current ground for improvement is placed is improved so that a building such as a house can be constructed on this ground.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, as shown in FIG. 1, the portion where the foundation is provided is clearly indicated on the current ground 1 by the ground rope, the white line 2, and the like. This clearly defined portion is an improved portion 3 for improving the current ground 1. Further, it is preferable that the improved width 3a of the improved portion 3 is set with a margin so as to be wider than the width of the foundation. Reference numeral 5 in the drawing is a usage method, and this usage method 5 is provided away from the position where the building is built in consideration of the improvement width 3a and the like. This method 5 is for stretching a water thread for centering the concrete foundation when forming the concrete foundation on the improved foundation ground 18.

Next, as shown in FIGS. 2 and 3, the improved portion 3 is excavated by the excavator 6. Excavate only the place where the foundation of the current ground 1 is provided and remove the topsoil 7. Reference numeral 7a in the figure
Is the removed topsoil.

On top of the base bottom 8 from which the topsoil 7 has been removed, a suitable amount of the solidifying material 9
Sprinkle on.

The thickness of the removed topsoil 7a is 200 mm in consideration of the softness of the topsoil 7.
In some cases, it may be good, and in other cases, it may be necessary to have about 700 mm.

As the solidifying material 9, a ground safety treating agent, cement or the like is used alone or in a mixture. As the ground stabilization agent, for example, Fuji Beton (trade name of Keio Kaken Kogyo Co., Ltd.) or Asano Clean Set 1140 (trade name of Nippon Cement Co., Ltd.) is suitable.

The base bottom 8 on which an appropriate amount of the solidifying material 9 has been sprinkled is also used for the excavator 6
Then, the excavated soil 10 and the solidifying material 9 are mixed and agitated to a depth of about 300 mm to 600 mm to obtain the first improved soil 11 (see FIG. 5).

The surface of the first improved soil 11 thus mixed and stirred is leveled by, for example, a bucket of the excavator 6, and the first improved soil 11 is temporarily rolled.

After the temporary rolling pressure is completed, the level of the first improved soil 11 is measured, and the operator corrects the place where the level difference is large or the place where there is uneven mixing.

After the correction of the level difference and the like, the first improved soil 11 is finally compacted by using a roller or the like (not shown).

After the completion of this compaction, water is sprinkled on the first improved soil 11 to adjust the water content ratio.

The base plate 12 is constructed by taking an appropriate curing period.

Reinforcement material formed on the base plate 12 in a lattice shape, a mesh shape, etc.
13 is provided (see FIG. 6).

As the reinforcing material 13, for example, plastic, rebar, bamboo, rope, cloth or the like is used. The reinforcing material 13 is basically formed in a lattice shape or a mesh shape, but it may be assembled in a single direction.

In this way, a new high quality earth and sand 14 is laid on the base plate 12 having the reinforcing material 13 arranged therein in an appropriate thickness, and an appropriate amount of the solidifying material 15 is sprinkled on the new earth and sand 14 ( (See FIG. 7).

The solidifying material 15 may be the same as the solidifying material 9 described above. As the high-quality new earth and sand 14, it is preferable to use well-drained mountain sand, river sand, sea sand, Masa earth, etc. alone or in combination.

A new soil 14 is sprayed with an appropriate amount of the solidifying material 15 by using the excavator 6 in the same manner to mix and stir to make the second improved soil 16 (see FIG. 8).

The surface of the second improved soil 16 thus mixed and stirred is leveled by, for example, an excavation bucket of the excavator 6, and the second improved soil 16 is temporarily rolled.

After the temporary rolling pressure is completed, the level of the second improved soil 16 is measured, and the operator corrects the place where the level difference is large or the place where there is uneven mixing. Further, the main rolling of the second improved soil 16 is performed using a roller or the like.

After the completion of this compaction, reconfirm the level of the second improved soil 16,
Water is sprayed on the second improved soil 16 to adjust the water content ratio.

Then, the upper ground 17 is constructed by taking an appropriate curing period.

In this way, the base plate 12 and the upper ground with the reinforcing material 13 interposed in the middle
A foundation ground 18 is constituted by 17 and. A foundation is built on this foundation ground 18.

FIG. 10 shows a state in which the foundation ground 18 configured as described above is bent due to uneven settlement or the like. Reference symbols A, B, in the figure
Especially tensile force is generated in C.

Even if the ground is bent in this way, the reinforcing material 13 shares the tensile force of the soil and suppresses the tensile force of the soil, so that the rigidity of the ground is increased and cracks do not occur.

(Effect of the invention) The upper ground improved by laying a new good quality earth and sand on the existing ground by removing the soft ground soil and improving the existing ground to an appropriate depth. In the above, a reinforcing material having a lattice shape, a mesh shape, or the like is interposed between the base board and the upper ground. Therefore, it is possible to obtain a foundation ground having improved compressive strength / shear strength and tensile strength.

It is economical because the ground of only the part that forms the foundation is improved.

Even if uneven subsidence occurs, the ground has tensile strength, so that the ground does not crack. Therefore, the building laid on the ground is stable.

[Brief description of drawings]

The drawings show an embodiment of the ground improvement method for foundation of the present invention.
The figure is a perspective view in which the part where the foundation is installed is clearly shown on the current ground by ground rope, white line, etc., Figures 2 to 9 show the procedure for implementing the ground improvement method for the foundation, and Figure 2 shows the excavator. Fig. 3 is a side view showing the work of removing topsoil using Fig. 3, Fig. 3 is a cross-sectional view of topsoil removed, Fig. 4 is a cross-section of the base bottom of the ground with topsoil removed, and Fig. 5 is a cross-section of Cross-sectional view of the first improved soil, Fig. 6 is a cross-sectional view of reinforcing material arranged on the base plate, and Fig. 7 is new quality sand and solidifying material on the base plate of reinforcing material. Fig. 8 is a cross-sectional view of the foundation and the second improved soil, Fig. 9 is a cross-sectional view of forming the upper ground on the foundation to form the foundation ground, and Fig. 10 is FIG. 6 is a cross-sectional view showing that the reinforcing material suppresses the tensile force of the soil even if the ground for foundation completed by the above method is unevenly settled. 1 ... Current ground, 2 ... Ground line, white line 3 ... Improved part, 5 ... How to use 6 ... Excavator, 7 ... Soil 8 ... Base bottom, 9,15 ... Solidifying material 11 ... First improved soil, 12 ... Base plate 13… Reinforcement material, 14… New quality sand 16… Second improved soil, 17… Upper ground 18… Foundation ground, A, B, C… Tensile force

Claims (1)

[Claims] 1. Excavating only the place where the foundation of the present ground is provided to remove the topsoil, and spraying an appropriate amount of the solidification material on the base bottom of the ground from which the topsoil has been removed, and the solidification material and an appropriate depth. After mixing and agitating the base bottom excavated on the base plate, rolling is performed to form a base plate, and a reinforcing material formed in a grid or mesh shape is arranged on the base plate. Improvement of foundation ground characterized by laying a new earth and sand with good thickness, mixing and stirring the new earth and sand and solidifying material, and then rolling to construct the upper ground to form the foundation ground Construction method.