JPH06116938A - Construction method for strip footing - Google Patents

Abstract

PURPOSE:To improve the efficiency of execution of a work and work execution precision by a method wherein a curing agent is mixed in soil at the lower part of the footing of a strip footing to agitate the mixture. CONSTITUTION:A curing agent is mixed in soil of a ground at the lower part of a footing 1 throughout width (b) of the footing 1 of a strip footing A to agitate the mixture. A stabilization processing ground B having a width of 1.5b-5b and a depth (b) or more is built, and the strip footing A is created thereon. A given amount of the curing agent is sprayed over a ground and after mixture and agitation are effected by means of an excavator, such as a shovel, a compaction is carried out by a press work and rolling compaction by means of a machine for compaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a cloth foundation whose ground is improved within a limited range.

[0002]

The construction of the cloth foundation that has been generally carried out in the past is performed by compacting the root cutting bottom ground with a compacting machine, laying split chestnuts, and if necessary throwing out concrete by discarding the footing portion of the cloth foundation. First, it is created, and the rising part of the cloth foundation is constructed on it. In this case, the bearing capacity may not be sufficient.

By the way, when constructing the foundation of a large-scale building, the ground is improved by injecting and mixing a solidifying agent over the entire ground to improve the ground bearing capacity. In this case, the construction efficiency and construction accuracy are not good.

The present invention is a method developed to improve the ground even for a cloth foundation, which is the basis of a relatively small-scale building, so as to provide a reliable bearing capacity of the foundation.

[0005]

The method of constructing a cloth foundation of the present invention has a width of 1.5b to 5b by mixing and stirring a solidifying agent with the earth and sand of the footing lower ground to the footing width b of the cloth foundation. , And stabilization treatment in the range of depth b or more,
A cloth foundation is created on the stabilized ground.

[0006]

EXAMPLE A cloth foundation A comprises a footing 1 and a rising portion 2. Reference symbol B indicates a stabilizing ground. Then, with respect to the width b of the footing 1, by mixing and stirring the solidifying agent with the soil in the ground below the footing 1, with a width of 1.5b to 5b,
A cloth foundation A is formed on a stabilized ground B having a depth of b or more. The above processing range is the range confirmed by the experiment.

The reason for adopting 1, 5 and 6 is the value obtained from the full-scale footing loading test, and the effect cannot be expected below this value. The reason for adopting 5b is that in the case of a two-story building, the maximum improved cross section is the improved thickness H = 1650m.
m, improved width B = 2100 mm, basic width b = 450
mm, 2100 mm / 450 mm = 4.7, and rounded up to 5.0.

The dispersion angle θ is generally 0 in the case of sandy soil.
= 30 °, θ = 45 ° in the case of viscosity, but 1: 2 was adopted in accordance with the “Building basic structural design standard / commentary”.

Further, the bottom surface of the footing 1, that is, the rooting depth D ₁ is located at the freezing depth, the stabilized ground B is deeper than the freezing depth, and the original ground C is at a depth where a Swedish sounding value Nsw ≧ 4 is obtained. And

When the X between the cloth foundations A and A is narrow, the width of the stabilized ground is X + H + b = B ≦ (b + H).

As the solidifying agent, a soil stabilizing treatment material such as cement or one having an effect equivalent to this is used.

[0012] For example, the product names are as follows.

Onoda Chemiko G-123, C-235 Stabilite M15, M20 Tough lock (1,2,3,4,5,6 type) Chichibu Soilfix Neocerament 400S Asano Clean Theft 100kg / m ³ when the natural moisture content W (%) of the silty sandy soil is 150 or less
It is not applicable when the water content is higher than that, and when W ≦ 200 in volcanic ash cohesive soil (loam) organic soil 15
0 kg / m ³ , 200 <W ≦ 300 200 kg / m ³
And

A predetermined amount of the solidifying material is scattered on the ground, mixed and stirred by an excavator such as a shovel, and then pressed by a compacting machine and compacted by rolling.

[0015]

EFFECTS OF THE INVENTION The present invention is constructed as described above, and because the stabilization treatment is applied only to the footing lower part of the cloth foundation, the construction efficiency and construction accuracy can be improved, and since the amount of excavated soil such as root cutting is small, it can be used as a temporary storage site. It is easy to secure space.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of another embodiment.

[Explanation of symbols]

A ... cloth foundation, B ... improved ground, C ... original ground, 1 ... footing, 2 ... rising part,

Claims (1)

[Claims] 1. Stabilizing treatment with a width of 1.5b to 5b and a depth of b or more by mixing and stirring a solidifying agent to the soil of the footing lower ground with respect to the footing width b of the cloth foundation. , A method for constructing a cloth foundation, which comprises forming a cloth foundation on the stabilized ground.