JPH0647803B2 - Construction method of constructed soil with permeability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention has a water permeability as a construction soil, does not freeze, has compressive strength and bending strength, and has a water permeability capable of being adapted to various uses. The present invention relates to the invention of a method for constructing soil.

(Conventional Technology) As a construction method for constructed soil, an economical soil cement method is generally used.

There are various uses of this soil cement construction method, such as roads, streets, roads of both rigid and twisted pavement, lower and upper roadbeds of airfields, surface treatment of slopes that are periodically and continuously subjected to flooding and waves, The core of the earth dam and the lining of the reservoir are the main ones.

The conventional soil cement method is applied to the site as described above, but until now, the soil to be used was selected, the amount of cement used was extremely large, and the water content was set to the optimum soil water content ratio to consolidate the soil. The main purpose was to obtain compressive strength and bending strength by mechanically compacting and curing.

Therefore, naturally, the constructed soil obtained by the soil cement method is impermeable to water, and is applied to the site where it must be impermeable, so the soil cement method with water permeability was considered until now. It never happened.

On the other hand, in sports surfaces, sidewalks, jogging courses, etc. of various sports stadiums, weakening of the ground surface due to rainwater is a problem because the use time and time are limited.

In addition, a lower roadbed of an athletic stadium, which is constructed using an artificial lawn or an artificial lawn filled with dry sand, has been studied recently.

Therefore, the inventors of the present invention have variously tried to apply the soil cement method to the sports surface, the lower roadbed of the artificial grass, the sidewalk, the jogging course and the like as described above.

However, it has been found that the soil cement method has a fatal drawback when it is used for the above-mentioned applications. It was impervious to water because it was originally impermeable, followed by frost heave in sub-zero regions and destruction of the soil surface by cold weather.

The property of soil cement is that when trying to increase water permeability,
It is a very difficult problem to solve the above drawbacks because there is a contradictory relationship that the compressive strength decreases, and the water permeability decreases when trying to increase the compressive strength.

In addition, of the sports arenas, clay tennis courts are required to be water permeable and have compressive strength to the extent that they have appropriate bound and cushioning properties, which is the most difficult sports surface in that sense. .

Therefore, one of the inventors of the present invention made some proposals regarding the construction method of the constructed soil having water permeability, and achieved a considerable result through the test.

However, these methods also have problems as described below.

(Problems to be solved by the invention) When constructing soil cement, the important point is to form a uniform layer with desired strength by compacting and compacting the whole in a short time at the optimum soil water content. To do.

However, in the conventional construction method of constructed soil, soil is mixed with hydraulic material (cement etc.) and water, and after leveling, leveling, etc., the compaction is performed, but if the constructed soil is small, there is a problem. If there is not a large amount, it takes time for leveling and leveling, so it will be compacted 5 to 6 hours after mixing water and hydraulic material, and the original strength cannot be obtained. Occurs.

Therefore, in general, a method of delaying the setting reaction of water and the hydraulic material by mixing a water-reducing agent has been taken, but commercially available water-reducing agents are very expensive and also expensive. Nevertheless, even if mixed, the effect of delaying the setting reaction and obtaining the desired strength could not be achieved.

As described above, the soil cement method has many problems especially in construction, but it is a very big attraction that the soil constructed by soil cement is inexpensive, and the inventors of the present invention dare to We have been working on solving the above-mentioned problems and have been conducting research.

Then, recently, new knowledge has been obtained through research and experiments, and the present invention has been completed based on this new knowledge.

(Means for Solving Problems) The configuration of the present invention will be described in detail with reference to examples.

First, the construction method of the present invention will be described. The soil used in the construction method of the present invention has a soil property of SL to LS according to the coordinates of the International (Soil Society) method.

The soil in this range has a property that it is easily mixed with a hydraulic material and the compressive strength is easily increased when it is compacted.

However, when the soil to be used is soil containing 5% or more of soil particles of 105 μ or less, the soil and the hydraulic material are mixed and coagulated as a pretreatment, and the soil property is in the range of SL to LS. Adjust the particle size before use.

An example of this case will be described. The soil water content of 1 m ³ of CL to L is set to be 15 to 40%, and the cement 30 to
If you mix it with 50 kg and leave it for a whole day and night, the soil will become SL.
The particle size can be adjusted to the soil in the range of to LS.

Incidentally, the hydraulic material referred to in the present invention, other than cement, means a material that hardens with water, such as gypsophila, lime, etc., and an organic acid aqueous solution exhibiting weak acidity is an aqueous solution of citric acid, tartaric acid, oxalic acid, etc. Is.

Further, the synthetic resin emulsion means ethylene vinyl acetate emulsion, acrylic emulsion, vinyl acetate emulsion, latex, etc., and the polymeric soil aggregating agent includes polyethylene oxide, polyacrylic amide, polyolefin, polyvinyl acetate. That is.

(Example) The compaction optimum soil water content ratio of soil having a soil property in the range of SL to LS is about 6 to 15% on the LS side and about 15 to 25 on the SL side.
%.

To tamp optimum soil water content 14.5% of soil 1 m ³ of soil was mixed with cement 100 kg, soil water content ratio is 1.27 times the compaction optimum soil water content ratio of the soil 18.4%
The water content of the soil was adjusted to 54.3 by mixing 100 g of citric acid in 54.3 of water with an aqueous solution of citric acid and 15 kg of ethylene vinegar emulsion, and then adjusting the water content.
After stirring, leveling, leveling, etc., 6 hours later, 4t
Roller applied 3-4 rotations.

The water permeability in that case was 4 × 10 ⁻⁴ cm / sec.

In this case, it is important to note that when the hydraulic material and the soil are compacted by soil compaction and compacted at the optimum soil water content ratio, there is no compressive strength, but there is water permeability. When compacted below, the water permeability is good, but the compressive strength is significantly reduced.

Further, when the soil is compacted at a soil water content ratio of 1.5 times or more of the optimum soil water content ratio, both the water permeability and the compressive strength decrease.

Therefore, if the soil is compacted at a soil water content ratio of 1.2 to 1.5 times the optimum soil water content ratio, it is possible to obtain sufficient compressive strength while maintaining good water permeability.

Next, in order to increase the bending strength of the soil surface and prevent the destruction of the soil surface due to the cold, the sheet is cured for 1 to 21 days, preferably 1 to 5 days after the completion of the compaction while curing the sheet. Two
/ Flexural strength of watering performing the soil surface of m ² whereas wards without watering 28 days material age is 2.1 kg / cm ^2,
It could be significantly increased to 2.7 kg / cm ² .

If water is sprinkled within 1 to 5 days after the completion of the compaction, the soil and the cement may not be strongly solidified.
When 0.03% aqueous solution is sprinkled, muddy water is not generated and the effect is more remarkable.

Next, the method of preventing frost heave will be explained. Generally, it is said that soil has an effect of suppressing frost heave when the compressive strength is 20 kg / cm ² or more.

In order to increase the strength, it is sufficient to spray water on the compacted surface at a rate of 1.5 to 2 / cm ² at least once in 7 to 21 days after the compaction is completed. Although it does not change, the compressive strength can be increased to 22.0 kg / cm ^{2 at the} age of 28 days.

Therefore, even if 6 hours have passed after stirring by adding an organic acid aqueous solution showing weak acidity so that the soil water content is 1.2 to 1.5 times the optimum soil water content by compacting the soil, it is possible to roll it. Nevertheless, it was possible to obtain a constructed soil that was permeable, did not freeze, and did not damage the soil surface due to cold weather.

By the way, the soil water content is 1.2 to the optimum soil water content of the soil.
Water was added to 1.5 times and the mixture was compressed 6 hours after stirring, but the compressive strength was 10 kg / cm ² at 28-day age, and the water-reducing retarder plastiment (trade name ...・ Nippon Sika Co., Ltd.) gave 14 kg / cm ² at 28 days of age.

Next, a method for constructing a lower roadbed of a sports stadium using a clay clay court and an artificial lawn at a site will be described. First, it is determined whether the site is floor-covered or floor-digged. Explaining the internal flooring site, crushed stone or sand sand of 0 to 40 mm is spread on the local roadbed to a thickness of 15 cm, and is rolled by a roller.

Next, bring in a good quality soil with a soil property of SL to LS to the site, or if using local soil, investigate whether it contains 5% or more of soil particles of 105 μ or less, and soil containing 5% or more If so, adjust the particle size with cement.

After crushing the above soil with crushed stone, spread it for about 15 cm, spray 100 kg / m ^{3 of} cement, and mix the soil and cement with a tractor or the like. The soil water content of this mixed soil was investigated, and 54.3 citric acid aqueous solution and 5% ethylene vinyl acetate were added to 1 m ^{3 of} soil so that the soil would be 1.2 to 1.5 times the optimum soil water content for compacting the soil. A mixture of 15 kg of emulsion is sprinkled with water, and the soil is stirred again with a tractor or the like. After this, temporary rolling with a 4t roller is performed two or three times, then the land is corrected, and then the final rolling is completed. When completed, in order to increase the bending strength of the soil surface, apply a sheet on it for 1 to 5 days while curing, and apply a 0.04% aqueous solution of polyethylene oxide at least once, 1-2 times.
/ M ^{2 was} sprayed, and in order to enhance the compressive strength between 7 and 21 days after the completion of construction, 1.5 to 2 / m ² of water was sprayed once or twice to complete the work.

(Function) When the test construction on site was carried out in the early November of 1987 by prohibiting outsiders from entering the ground owned by the applicant, and the wintering condition was investigated in the middle of February 1988, there was no freezing and compression. The strength is 22.5 kg / cm ² , and the bending strength is 3.
The water permeability was 1 kg / cm ² , and the hydraulic conductivity was 4 × 10 ⁻⁴ cm / sec, which was almost the same as that of the 28th day.

In addition, the general clay coat formed in the ground had completely frozen up and was so weak that it could not be used due to rainwater.

(Effect of the invention) As described above, the soil cement constructed by the construction method for constructing a water-permeable soil according to the present invention is added with an organic acid aqueous solution exhibiting a weak acidity to change the soil water content to that of the soil. Since it is adjusted to 1.2 to 1.5 times the optimum soil moisture content,
Even if it takes a long time to spread the soil and level it after adjusting the soil compaction ratio to 1.2 to 1.5 times the optimum soil water content ratio, the initial purpose is Compressive strength is obtained.

Therefore, the soil compaction optimum soil water content ratio of 1.2 to 1.
Even if the soil cement is simply adjusted to 5 times, or the soil cement that is mixed with an expensive commercially available water-reducing retardant and is adjusted to 1.2 to 1.5 times the optimum soil water content for compacting the soil When a long time was required afterward, the initial desired compressive strength could not be obtained, but such problems in construction disappeared.

Moreover, at least 1 is applied to the rolling surface within 1 to 21 days after the rolling is completed.
Since water is sprinkled once or twice / m ² times, it has the effect that the soil surface has bending strength and water permeability.

Furthermore, even if the soil used is soil containing 5% or more of soil particles of 105 μ or less, as a pretreatment, the soil and the hydraulic material are mixed and coagulated to change the soil to a soil in the SL to LS range. Since the particle size is adjusted before use, the soil used is not limited.

Therefore, the conventional soil cement method has never been thought of as water permeability, but the construction method of the constructed soil of the present invention not only has water permeability, but also has compressive strength, bending strength, and ideally does not freeze. Since it can provide a structured soil and is as economical as the soil cement method, the construction method of the constructed soil of the present invention can be applied to sports surfaces of various athletic stadiums, of which tennis is said to be the most difficult. Clay court, sidewalk, jogging course,
Or if it is used for the lower roadbed of an artificial lawn sports stadium, it is optimal because it has compressive strength, water permeability, good drainage, and it does not freeze up even in a place below freezing. Since it does not suffer surface damage due to cold, it has special effects such as being applicable to uses that could not be applied by the conventional soil cement method.

Claims (3)

[Claims] 1. When constructing soil, the soil is SL.
To LS, the soil and the hydraulic material are mixed, and the soil water content is compacted to squeeze the soil to an optimum soil water content of 1.2 to 1.5.
A method for constructing a constructed soil having water permeability, which comprises adding an organic acid aqueous solution showing weak acidity so as to double the amount, and stirring and then rolling. 2. When constructing soil, the soil is SL
~ LS soil and hydraulic material are mixed, and the organic acid aqueous solution showing weak acidity is added so that the soil water content ratio is 1.2 to 1.5 times the optimal soil water content ratio for compacting the soil. A method for constructing a constructed soil having water permeability, which comprises: after agitation and after compaction, water is sprayed onto the compacted surface at least once within 1 to 21 days. 3. 5% of soil particles of 105μ or less as pretreatment
The soil having a water content ratio of 10 to 40% contained above is mixed with a hydraulic material to adjust the particle size of the soil property in the range of SL to LS, and the particle size adjusted soil and the hydraulic material are mixed, The soil water content ratio is tamped with the soil to add 1.2 to 1.5 times the optimum soil water content ratio, and an aqueous solution of an organic acid that exhibits weak acidity and an aqueous solution of a synthetic resin emulsion are added, and the mixture is stirred and then compacted. ~ 5
A method for constructing a constructed soil having water permeability, which comprises spraying an aqueous solution of a soil aggregating agent at least once during a day, and further spraying at least once during 7 to 21 days after completion of compaction.