JPS5882142A - Continuous collecting method of solidified soil sample - Google Patents

Abstract

PURPOSE:To make it possible to take samples of solidified soil including the soil which has not enough mixing and agitation by giving vibration to a soil to be improved and charging it with pressure into a sampling pipe before solidification of the soil mixed and agitated with a solidifying material. CONSTITUTION:A soil B to be improved in a soft, weak and viscous ground A is mixed and agitated with a hardening agent that is supplied by a deep layer mixing machine and so on, and while the soil B has not yet solidified, a long, bottom-opened sampling pipe 4 is pressed into the soil B with vibration given to the pipe 4 by a vibrator 2 that is hung from a hoist 1 of leader type. When the pipe 4 is sunk to a specified depth, it is left there for a while, and the soil sample in the pipe with the soil that is not imcomplete with agitation and mixing is cured to solidify. When a soil sample has solidified the sampling pipe 4 is pulled up to the ground floor with air being sent through an air pipe 5, and a solidified soil sample is subjected to strength test for each depth. In this way the true strength of the whole of a solidified pile can be known.

Description

Detailed Description of the Invention The present invention supplies a solidifying agent such as cement or quicklime into a soft and viscous soil, stirs and mixes it with the soil to be improved, and creates a chemically strong and chemically stable solidified material in the soil. This invention relates to a method for continuously collecting compacted soil samples in the so-called deep mixing method for creating compacted piles.

Conventionally, the common method for collecting compacted soil samples in this type of construction method is to perform far sampling by polling after the compacting material supplied into the soft and cohesive soil and the soil to be improved are stirred and mixed and completely compacted. It is. However, stirring and mixing of the solidification material and the soil to be improved in situ is usually done in a short period of time due to time constraints, which tends to result in non-uniform mixing. Therefore, when performing core sampling by polling the soil to be improved, even if a so-called double core barrel or triple core barrel method is adopted, fractures may occur at points where stirring and mixing are incomplete, resulting in a continuous compacted soil sample. Normally, this is not possible. Therefore, when strength tests are performed on these samples, the strength of only well-stirred and mixed compacted soil samples will be obtained, and there will be a large difference from the true strength of the entire compacted pile.

In addition, even if a thin wall sampler, which is widely used to collect undisturbed samples especially in cohesive soil, is adopted, the soil flowing into the sampling tube will be affected by the frictional resistance of the inner surface of the sampling tube. The top may be compressed or the soil at the bottom of the sampling tube may be pushed downwards, making it impossible to enter any further.

It is said that the maximum sampling length of soil flowing into the sampling tube is /n or more.

The present invention was made in consideration of the above problems, and its purpose is to obtain a soil that is close to the true strength of a consolidated pile from the soil to be improved which has been stirred and mixed with the consolidation agent supplied into the soft and viscous soil. The object of the present invention is to provide a method for continuously collecting compacted soil samples including incompletely stirred and mixed portions in order to ascertain the values.

Embodiments of the present invention will be described below with reference to the drawings.

No is a leader type lifting machine, Ko is an exciter,
It is suspended from the lifting machine 1 via a wire 3. 1 is a long sampling pipe with an open bottom end, and is fixed to the exciter.

The outer surface of the sampling pipe is equipped with an air pipe 5 extending in the axial direction to the lower end.

The upper end of the air pipe S is connected to an air compressor 7 on the ground via an air hose 6.

First, the soil B to be improved in the soft and viscous ground A is stirred and mixed with an assimilated material supplied by a deep mixer (not shown) or the like. Then, the soil B to be improved is converted into a consolidated pile over time, but at the stage where the soil B to be improved including the solid material and the material has not yet solidified, it is preferable to
When the chemical reaction with the solidification material has not yet started, vibrations are applied to the soil B to be improved using a vibrator suspended from a leader-type lifting machine inside a long Sambli jig pipe with an open bottom end. press fit while At this time, + flowing into the sampling pipe q continuously flows while cutting the frictional resistance on the inner surface of the sampling pipe q due to the action of the applied vibration. According to experiments, it has been confirmed that even if a sampling pipe with a length of 10 m or more is used, the top of the inflow is not compressed, and the soil at the bottom end of the pipe is not forced downward, and the soil can be continuously inflowed.

In addition, disturbance of the sample on the inflow into the Sanbri jig pipe due to vibration during press-in does not pose a major problem because the soil to be improved is the disturbed ground immediately after being stirred and mixed with the solidification material.

In this way, once the sampling tube is press-fitted to a predetermined depth, it is left for a certain period of time.

Then, the soil sample including the incompletely stirred and mixed portion with the assimilated material in the sampling is subjected to assimilation curing.

Once the soil sample has solidified, the sampling viper is pulled up. At this time, the sampling pipe is pulled out to the ground while sending air through the air pipe 5 to prevent the compacted soil sample inside the pipe from falling due to the vacuum generated at the lower end of the sampling pipe. , the compacted soil sample extracted from the sampling pipe was
(Subjected to strength tests at each depth.

For the sampling pipe, it is best to use a steel pipe that can be disassembled into pieces in the axial direction on the ground, or a vinyl chloride pipe that can be cut on the ground with a cutter.

According to this invention, a long sampling pipe with an open bottom end is inserted into the soil to be improved, which is stirred and mixed with a solidification material supplied into a soft and viscous soil, at a stage that has not yet reached solidification, without applying vibrations. After the soil sample inside the sampling pipe was press-fitted and left to solidify and cure, the sampling pipe was pulled out to the ground while sending air to the lower end, so it included the part where the stirring and mixing with the solidifying material was incomplete. Since continuous samples of compacted soil can be collected, it is possible to know the true strength of the entire compacted pile, and at the same time, according to the present invention, it can be carried out easily and efficiently, and it can produce accurate flavoring results. Because it can be obtained, its contribution to geological investigation is significant.

[Brief explanation of drawings]

Figure 1 is a side view showing the state in which the sampling pipe used in the method of the present invention is press-fitted into soil to be improved that has not yet solidified, Figure 2 is a cross-sectional view of the sampling pipe, and Figure 3 is the same as in Figure 2 (7). ) There is also a cross-sectional view taken along line X-X. L...Leader type lifting machine...Exciter D...Sampling pipe S...Air pipe A...Soft viscous soil plate B...Soil to be improved Patent applicant Obayashi Corporation Agent Junji Okada Figure 1 Figure 2

Claims (1)

[Claims] A long sampling vibrator with an open bottom end is press-fitted into the soft, viscous soil that has been stirred and mixed with the solidifying material while applying vibration, and the sample inside the sampling vibrator is left for a certain period of time. After solidifying and curing,
A method for continuously collecting consolidated soil samples, characterized in that the sampling pipe is pulled out while sending air to the lower end.