JPS63280113A - Ground improving work for foundation - Google Patents

Abstract

PURPOSE:To increase the strength of the ground by a method in which surface soil is removed, soil is newly laid on the ground to form an improved lower ground, a reinforcing material is laid on the ground, and soil is newly placed on them. CONSTITUTION:Good-quality soil 9 is placed on the base ground 8 deprived of its surface soil 7 and mixed with a solidifying agent 10 by stirring, and the ground is tamped to form a lower ground 12. A latticed and meshed reinforcing material 13 is laid on the ground 12, and good-quality soil 14 is newly placed on it. The soil 14 and the solidifying agent 15 are mixed together with stirring and tamped to form an upper ground 17. The foundation ground 18 having improved compressive strength, improved shear strength, and improved tensile strength can thus be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a foundation ground improvement method aimed at preventing uneven settlement of lightweight buildings or destruction of concrete foundations due to soft ground.

(Prior art) When constructing a building such as a house on soft ground, the ground is improved in advance by adding a solidification material to the soft ground,
This prevented uneven settlement of lightweight buildings or destruction of concrete foundations due to soft ground. Conventionally, ground improvement has been carried out over the entire area of the site on which the building will be built.

(Problem to be solved by the invention) The ground improved by adding a solidifying agent has compressive strength and shear strength, but has no tensile strength. There was a problem with the crank getting stuck in the ground.

In addition, in order to prevent uneven settlement of buildings or destruction of concrete foundations, the foundations are placed in places where the strength of the ground is required, and other locations do not necessarily require extensive ground preparation such as adding solidifying materials. No improvement required. Therefore, if the ground is improved over the entire site as in the past,
There were problems in that a large amount of assimilated materials and other materials were required, and the construction cost was high due to the long construction time.

(Means for Solving the Problem) The present invention excavates only the area where the foundation will be installed in the current ground, removes the topsoil, and adds new high-quality soil to the base bottom of the ground from which the topsoil has been removed. After the new earth and sand and solidification material are mixed and stirred, compaction is performed to form the base.
A reinforcing material formed in the form of a lattice or mesh is placed on top of this base ground, and new high-quality soil is laid down to an appropriate thickness on top of this reinforcing material. This is a soil improvement method for foundations in which the upper ground is formed by mixing and stirring and then rolling it into the foundation ground.

(Operation) To improve only the part of the current ground where the foundation will be placed for the purpose of improvement, making it possible to construct buildings such as houses on this ground.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

First, as shown in Figure 1, the part where the foundation will be installed is clearly marked on the current ground level l by ground lines, white lines 2, etc. This clearly defined area will be the improved area 3 where the current ground 1 will be improved. Further, it is preferable that the improved width 3a of the improved portion 3 is set to be wider than the width of the foundation. The reference numeral 5 in the figure is a construction, and this construction 5 is provided at a distance from the position where the building is to be constructed, taking into account the improvement width 3a and the like. This method 5 is based on the improved foundation ground 18
When a concrete foundation is formed on top of the concrete foundation, it is used to align the center of the concrete foundation and to span the water system.

Next, as shown in FIGS. 2 and 3, the improved portion 3 is excavated by an excavator 6. Topsoil 7 will be removed by excavating only the area where the foundation will be installed on the current ground 1. Code 7 in the diagram
A is the removed topsoil.

The thickness of the topsoil 7a to be removed is 20 mm considering the softness of the topsoil 7.
There are cases where 0m is sufficient, and there are cases where about 1,000 meters are required.

An appropriate amount of new soil 9 of good quality is laid on the base bottom 8 of the ground from which the topsoil 7 has been removed in this way. By scattering an appropriate amount of solidification material 10 on top of this new soil 9 of good quality and mixing and stirring these assimilation materials 10 and new soil 9 of good quality using an excavator 6, the first improvement ±11 (See Figure 5).

As the new soil 9 of good quality, it is preferable to use well-drained soil, river sand, sea sand, masa soil, etc. singly or in combination.

As the solidifying material 10, a ground stabilizing agent, cement, etc. are used alone or in combination. As the ground stabilization treatment agent, for example, Fujibeton (trade name of Keio Kaken Kogyo Co., Ltd.) or Asatsu Clean Set 1140 (trade name of Nippon Cement Co., Ltd.) is suitable.

The surface of the first improved soil 11 described above is leveled using, for example, a packet of the excavator 6, and the first improved soil 11 is temporarily compacted.

After the preliminary rolling is completed, the level of the first improvement ±11 is measured, and the operator corrects areas where the level difference is large or where there is uneven mixing.

After correcting this level difference, etc., the first improved ±11 is rolled to zero using a roller or the like (not shown).

After the main compaction is completed, water is sprinkled on the first improved ±11 to adjust the water content ratio.

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

A reinforcing material 13 formed in the form of a lattice, a mesh, etc. is provided on the base 12 (see FIG. 6).

As the reinforcing material 13, for example, plastic, reinforcing steel, bamboo, rope, cloth, etc. are used. The reinforcing material 13 is basically formed in a lattice shape or a mesh shape, but may also be constructed in a single direction.

New soil 14 of good quality is laid down to an appropriate thickness on top of the base 12 on which the reinforcing material 13 has been placed, and
An appropriate amount of solidification material 15 is sprinkled on top of this new earth and sand 14 (see Figure 7).

The solidifying material 15 may be the same as the solidifying material 10 described above.

Furthermore, the new high-quality soil 14 may be the same as the above-mentioned new high-quality soil 9.

New soil 14, on which an appropriate amount of solidification material 15 has been sprinkled, is mixed and stirred using the excavator [6] to form the second improved soil 1.
6 (see Figure 8).

The surface of the second improved soil 16 mixed and stirred in this way is leveled with, for example, an excavation packet of the excavator 6, and
The second improved soil 16 is temporarily compacted.

After the preliminary rolling is completed, the level of the second improvement ±16 is measured, and the operator corrects areas where the level difference is large or where there is uneven mixing.

Further, a second improved zero rolling pressure of ±16 is performed using a roller or the like.

After the main compaction is completed, the level of the second improvement ±16 is reconfirmed, and water is sprinkled on the second improvement ±16 to adjust the water content ratio.

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

In this way, the foundation ground 18 is constituted by the base ground 12 and the upper ground 17 with the reinforcing material 13 interposed between them (9th
(see figure). A foundation is constructed on this foundation ground 18.

Note that one or more improved grounds may be formed between the base ground 12 and the upper ground 17, and the reinforcing material 13 may be interposed between each of these improved grounds.

FIG. 10 shows a state in which the foundation ground 18 constructed in this manner is bent due to the inequalities.

In particular, tensile forces are generated at symbols A, B, and C in the figure.

Even if the ground bends in this way, the reinforcing material 13 takes part in suppressing the tensile force of the soil, increasing the rigidity of the ground and preventing cracks from occurring.

(Effect of the invention) New soil of good quality is laid and improved on the ground from which the soft topsoil has been removed, and it is used as the base ground, and new soil of good quality is laid and improved again on top of this base ground. A reinforcing material such as a lattice or mesh is interposed between the base and the upper ground. Therefore, it is possible to obtain foundation soil with increased compressive strength and shear strength as well as increased tensile strength.

Since the sub-soil is also composed of new, high-quality earth and sand, it is possible to obtain foundation soil with higher compressive and shear strength.

It is economical because only the ground that makes up the foundation is improved.

This ground has tensile strength, so even if uneven settlement occurs, cracks will not form in the ground.

Therefore, buildings built with foundations on such ground are stable.

[Brief explanation of drawings]

The drawings show an embodiment of the foundation ground improvement method of the present invention.
The figure is a perspective view showing the area where the foundation will be installed on the current ground using ground lines, white lines, etc. Figures 2 to 9 show the procedure for implementing the soil improvement method for foundations, and Figure 2 shows an excavator. Fig. 3 is a cross-sectional view with the topsoil removed, and Fig. 4 is a side view showing the work of removing topsoil using soil. Figure 5 is a cross-sectional view of the first improved soil, Figure 6 is a cross-sectional view of the reinforcement material placed on top of the base ground, and Figure 7 is the reinforced soil. Fig. 8 is a cross-sectional view of the sub-soil and second improved soil, and Fig. 9 shows the upper sub-soil on top of the sub-soil. FIG. 10 is a sectional view showing that the tensile force of the soil is suppressed by the reinforcing material even if the foundation ground completed in this way sinks unevenly. 1...Current ground 2...Ground line, white line 3...
・Improved part 5... How to use 6... Excavator
7... Topsoil 8... Base bottom 10.15.
...Solidification material 11...First improvement± 12...Base ground 13...Reinforcement material 9,14...New earth and sand of good quality 16...Second improvement± 17...Upper ground 1
8...Foundation ground A, B, C...Tensile force IF
Figure 7 Figure 3 IF5 Figure 5 Figure 6 Figure 7 Figure 8 Figure 1 to 9 Figure 11810 Figure

Claims (1)

[Scope of Claims] 1) Excavate only the area where the foundation is to be installed in the current ground, remove the topsoil, and lay new soil of good quality on the base bottom of the ground from which this topsoil was removed. After mixing and stirring the soil and solidification material, compaction is performed to form a sub-base. A reinforcing material in the form of a lattice or mesh is placed on top of this sub-base. A soil improvement method for foundations, which is characterized by laying good new earth and sand to an appropriate thickness, mixing and stirring this new earth and sand with a solidifying material, and then rolling compaction to form the upper ground and use it as foundation ground. .