JPH0639780B2 - Ground improvement method for buildings - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a ground improvement method for a building for 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, if the ground for the building is soft, the ground is improved in advance by adding a solidifying material to the soft ground, etc. It prevented uniform settlement or destruction of the concrete foundation. Conventionally, the ground has been improved for the entire area of the site where the building is built (the invention described in JP-A-54-96207).

Further, it has been known that the improvement target is limited only to a place where a foundation is provided (the invention described in JP-A-59-187921).

(Problems to be solved by the invention) However, the place where the strength of the ground is required to prevent the uneven settlement of the lightweight building or the destruction of the concrete foundation is the place where the foundation is arranged, and the other positions are Large-scale ground improvement such as adding a solidifying material is not always necessary. Therefore, when the ground is improved over the entire area of the site as in the conventional art, there is a problem that there are many materials such as a solidifying material and the construction cost is high because of the construction time.

Both the invention for improving the ground over the entire area of the site and the above-described conventional invention in which the object to be improved is limited to the place where the foundation is provided, both aim to improve only the topsoil of the ground.

In the case of laying a concrete foundation in these conventional inventions, it is necessary to further excavate the improved ground to form the footing portion of the foundation on the improved ground, which results in waste of construction work. In addition, it improves the whole topsoil and improves unnecessary parts.

(Means for Solving Problems) In the ground improvement method for a building of the present invention, in the current ground for improvement, only a place where a concrete foundation is laid is excavated to a base bottom of an appropriate depth, and The base bottom is further excavated by the improved thickness, and the solidified material is sprinkled on the excavated soil to be improved, and both are mixed to form mixed soil, and then temporary rolling pressure is applied to this mixed soil and the water content ratio is adjusted. After adjusting the level of the mixed soil, the main rolling of the mixed soil is performed to further adjust the water content ratio.

(Operation) For the purpose of improvement, only the place where the foundation of the current ground is placed is excavated and improved, and the concrete foundation of the building such as a house is built on the excavated and improved ground.

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

1 to 8 show a process of improving the building ground, and the same parts are designated by the same reference numerals in the drawings.

First, as shown in FIG. 1, the portion on which the foundation is laid 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 farther 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 base bottom 7 of the improved portion 3.

Next, as shown in FIGS. 2 and 3, the excavator 6 is used to move the improved portion 3 to the fuchin portion (base) of the concrete foundation.
Excavate to the depth at which the so-called base bottom 7 is provided. After that, the level is measured using the level measuring tool 8 or the like, and the excavation depth is confirmed. Reference numeral 9 in the figure denotes excavated soil which has been piled up on the current ground 1 by the excavator 6.

Further, the base bottom 7 is excavated by the excavator 6 while maintaining the improved width 3a. The depth excavated here becomes the improved thickness 3b. After confirming the improved thickness 3b using the level measuring tool 8 or the like, a ground stabilizing agent and a solidifying material 11 such as cement are added to the excavated improved soil 10 (see FIG. 4).

Then, after the soil to be improved 10 and the solidifying material 11 are sufficiently mixed and agitated, the agitated mixed soil 12 is temporarily compressed by the excavation bucket 6a of the excavator 6 or the like (see FIG. 5). . When the excavated soil 10 and the solidifying material 11 are mixed and stirred, an appropriate amount of water is sprayed as necessary to adjust the water content ratio.

After the temporary rolling pressure is completed, the level of the mixed soil 12 and the current ground 1 is measured, and the operator corrects the place where the level difference is large or the place where there is uneven mixing (see FIG. 6).

Further, the mixed soil 12 is subjected to main rolling by a rammer 13, rollers 14, etc. (see FIGS. 7 and 8).

After the completion of this compaction, reconfirm the level and spray water to adjust the water content ratio. The solidifying material 11 is mixed, for example, at 100 kg / m ² or more. Then, by taking an appropriate curing period, the ground improvement is completed.

The foundation is laid on the improved ground improved as described above.

(Effects of the Invention) As described above, according to the ground improvement method for a building of the present invention, since the ground is improved only at the place where the concrete foundation is arranged, the amount of the material such as the solidifying material used can be reduced as compared with the conventional method. At the same time, the construction time can be shortened and the construction cost can be reduced.

Further, only the portion below the base bottom where the fuchin portion of the concrete foundation is provided is improved. Therefore, the concrete foundation may be formed directly on this improved ground. In other words, unnecessary work such as further excavation of the improved ground to form a concrete foundation is unnecessary. Further, since the portion below the bottom of the base is modified, unnecessary modification is not required, which is efficient.

[Brief description of drawings]

1 to 8 are process drawings showing the ground improvement method for buildings of the present invention. 1 …… Current ground, 3 …… Improvement part 11 …… Solidification material, 12 …… Mixed soil

Claims (1)

[Claims] 1. In the existing ground for the purpose of improvement, only a place where a concrete foundation is laid is excavated to a base bottom having an appropriate depth, the base bottom is excavated by a further improved thickness, and the excavated improvement is performed. After the solidifying material is sprayed on the planned soil and the two are mixed to form mixed soil, the mixed soil is tentatively compressed, the water content ratio is adjusted, and the level of the mixed soil is adjusted. This is a method for improving the ground for buildings, which is characterized by performing the main compaction and further adjusting the water content ratio.