JPH0473485B2 - - Google Patents

Description

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

(Prior Art) Conventionally, when constructing a house or the like on soft ground, ground countermeasures have been taken using slab foundations, pile foundations, etc.

(Problems to be Solved by the Invention) A solid foundation is effective in sandy ground, and in clay ground it is effective in reducing the ground contact thickness, but the construction cost is extremely high and it is uneconomical.

In addition, pile foundations cause environmental pollution problems due to noise and vibration during driving, and the construction cost is considerably higher than the total building cost, making it an uneconomic construction method.

(Means for solving the problem) The construction ground improvement method of the present invention excavates the existing ground over the entire area of the construction site and removes the topsoil with a thickness of approximately 300 to 500 mm. After scattering an appropriate amount of solidification material on the base bottom of the ground, excavate the base bottom to a depth of approximately 300 to 600mm, mix and stir the excavated soil and solidification material, and prepare the first improved soil. The surface of the mixed and stirred first improved soil was leveled and preliminary compaction was performed, and after adjusting the level of this first improved soil surface, main compaction was performed, and the main compacted first improved soil was sprinkled with water. A first improved soil layer is formed by adjusting the moisture content and curing, and on top of this first improved soil layer, new soil of good quality is laid down to an appropriate thickness, and on top of this new soil. After spraying an appropriate amount of solidification material, the solidification material and new soil are mixed and stirred to obtain second improved soil.The surface of this second improved soil is leveled and subjected to temporary compaction, and then the second improved soil is prepared. After adjusting the level of the soil surface, main compaction is performed, and the second improved soil layer is formed by sprinkling water on the main compacted second improved soil to adjust the moisture content and curing it. .

(Operation) The topsoil, which is generally soft, is removed over the entire area of the construction site, and an appropriate amount of solidification material is sprinkled on the base bottom of the removed ground, and this solidification material and the excavated soil are added to the base bottom. Mix and stir to form a first improved ground layer containing the first improved soil, lay new soil of good quality on top of this first improved soil layer, and mix and stir this new soil and solidification material. The ground for construction is improved by forming a second improved ground layer having second improved soil.

(Example) The drawings show an example of the construction ground improvement method of the present invention.

First, an excavator 1 is used to excavate the existing ground 2 over the entire area of the construction site, and topsoil 3 with a thickness of about 300 to 500 mm is removed. The thickness of the topsoil 3 to be removed is topsoil 3
In some cases, 200mm may be sufficient considering the softness of
In some cases, about 700mm is required.

The base bottom 4 of the ground from which the topsoil 3 has been removed in this way
An appropriate amount of solidifying material 5a is sprinkled on the area. As the solidifying material 5a, a ground stabilizing agent, cement, etc. are used alone or in combination. As a ground stabilization treatment agent, for example, Fujibeton (trade name of Keio Kaken Kogyo Co., Ltd.) or Asano Clean Set 1140
(trade name of Nippon Cement Co., Ltd.) etc. are suitable.

The base bottom 4, on which an appropriate amount of solidification material 5a has been sprinkled, is similarly excavated to a depth of about 300 to 600 mm using the excavator 1, and the excavated soil 6 and the solidification material 5a are mixed and stirred to form the first improved soil 7a. do.

The surface of the thus mixed and stirred first improved soil 7a is leveled using, for example, the excavation bucket 1a of the excavator 1, and the first improved soil 7a is temporarily compacted. After the preliminary compaction is completed, the level of the first improved soil 7a is measured, and the operator corrects areas where the level difference is large or where there is uneven mixing. The first improved soil 7a is subjected to main compaction using a rammer 8, rollers 9, etc.

The first improved soil layer A is formed by spraying water on the first improved soil 7a which has been temporarily compacted in this manner to adjust the water content ratio and curing it.

Next, on this first improved ground layer A, new soil 10 of good quality is laid with an appropriate thickness, and after scattering an appropriate amount of solidification material 5b on this new soil 10, this solidification material 5b and The new soil 10 is mixed and stirred to form second improved soil 7b.

As the new soil 10 of good quality, it is preferable to use well-drained mountain sand, river sand, sea sand, masa soil, etc. singly or in combination.

As in the case of the first improved soil 7a, the surface of the second improved soil 7b mixed and stirred in this way is leveled using, for example, the excavation bucket 1a of the excavator 1, and the second improved soil 7b is temporarily Roll pressure.

After the preliminary compaction is completed, the level of the second improved soil 7b is measured, and the operator corrects areas where the level difference is large or where there is uneven mixing.

Further, the second improved soil 7b is subjected to main compaction using a rammer 8, rollers 9, etc.

After the main compaction is completed, the level of the second improved soil 7b is reconfirmed, and water is sprinkled on the second improved soil 7b to adjust the water content ratio. The improvement of the ground is then completed by forming the second improved ground layer B by taking an appropriate curing period.

The foundation will be constructed on the ground that has been improved as described above.

The solidifying material 5a used for the first improved soil 7a and the solidifying material 5b used for the second improved soil 7b may be the same or different. For example, a ground stabilizing agent may be used as the solidifying material 5a, and cement may be used as the solidifying material 5b. It may also be used in the opposite way.

(Effect of the invention) The construction ground improvement method of the present invention removes the topsoil of the existing ground over the entire area of the construction site to an appropriate depth,
The ground from which this topsoil has been removed is improved using a solidification material to form the first improved ground layer with the first improved soil, and new high-quality soil is laid on top of this first improved soil. By mixing and stirring new earth and sand and solidifying material, a second improved ground layer having second improved soil is obtained. Since the second improved ground layer is formed after completing the first improved ground layer, it is possible to stably form an improved ground with a complete two-layer structure. Therefore, the topsoil, which is a soft ground, is removed, and the ground from which this topsoil has been removed and the new soil form separate improved ground layers, further increasing the improvement effect and creating a stable ground. buildings can be constructed.

[Brief explanation of the drawing]

The drawings show an embodiment of the ground improvement method for construction according to the present invention. Fig. 1 is a cross-sectional view of the current ground being excavated using an excavator, and Fig. 2 is an enlarged cross-section of the excavated ground with solidifying material sprinkled on the bottom of the base. Figure 3 is a cross-sectional view of forming the first improved ground layer with the first improved soil, Figure 4 is a cross-sectional view of the new earth and sand laid on top of the first improved soil layer, with the solidification material being spread. Figure 5 is a cross-sectional view of a worker leveling the surface of the second improved soil, Figure 6 is a cross-sectional view of the first improved soil and second improved soil being compacted using a rammer, and Figure 7 is a cross-sectional view of the worker leveling the surface of the second improved soil. It is a sectional view showing the first improved soil and the second improved soil being compacted using rollers. 1...Excavator, 2...Current ground, 3...Top soil,
4... Base bottom, 5a, 5b... Solidifying material, 6...
Excavated soil, 1a... Excavation bucket, 7a... First improved soil, 7b... Second improved soil, 8... Ranma, 9...
...Roller, 10...New soil of good quality, A...
First improved ground layer, B...Second improved ground layer.

Claims (1)

[Claims] 1 Excavate the current ground throughout the entire construction site and excavate approximately
After removing the topsoil with a thickness of about 300 to 500 mm and spraying an appropriate amount of solidification material on the base bottom of the ground from which the top soil was removed, excavate the base bottom to a depth of about 300 to 600 mm. The excavated soil and solidification material are mixed and stirred to obtain the first improved soil, and the surface of the first improved soil thus mixed and stirred is leveled and preliminary compacted to adjust the level of the surface of this first improved soil. After that, the first improved soil is compacted, and the first improved soil is sprinkled with water to adjust the moisture content and cured, thereby forming the first improved soil layer. After laying new soil of good quality to an appropriate thickness and scattering an appropriate amount of solidification material on top of this new soil, this solidification material and new soil are mixed and stirred to form the second improved soil. Level the surface of the second improved soil and perform preliminary compaction, then adjust the level of the surface of the second improved soil, perform main compaction, and adjust the water content by sprinkling water on the second improved soil that has been fully compacted. A construction ground improvement method characterized by forming a second improved ground layer by curing and curing.