JP2001321759A - Method for determining compounding for improving physical properties of building surplus soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability in the determination of compounding when building surplus soil generated on a site of construction is recycled as physical property improved soil by compounding a hardening agent and water with the building surplus soil. SOLUTION: This method for determining compounding for improving physical properties of building surplus soil comprises a process (A) for preliminarily measuring both of the physical properties of plural kinds of building surplus soils and the physical properties of many kinds of treated soils for testing prepared by compounding a material such as the hardening agent, water or the like with the building surplus soils in various compounding ratios to accumulate data showing the relation of the characteristics of both of them and a process (B) for measuring the physical properties of building surplus soil to be improved and collating them with the accumulated data to determine the compounding for improving the physical properties of the building surplus soil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a soil with improved properties by blending a solidifying agent and water with construction waste soil generated at a construction site and recycling the construction waste soil, The present invention relates to a method for determining the composition of water.

[0002]

2. Description of the Related Art In order to reduce the amount of waste generated during construction at construction sites and to reuse it, the remaining soil is fluidized to produce soil with improved physical properties. The soil with improved physical properties is used as various types of backfill soil. Reuse has been done for some time. When determining the composition of the soil with improved physical properties, a part of the target soil after construction is sampled in advance for testing, its water content is measured, and a solidifying agent (mainly cement is used) ) And water, by changing the compounding amount in several stages, to produce several types of soil for property improvement for testing,
The specific gravity,
It is common to measure the flow value, breathing, and uniaxial compressive strength, and to use the basic composition of a test property-improved soil that satisfies the specified quality. If the value is not much different from the residual soil generated by the test construction, the basic composition is followed, and if there is a difference, the method is adjusted by the amount of water.

[0003]

By the way, even if the moisture content of the new construction waste soil is the same as the moisture content of the test construction waste soil, the other physical properties are different from those of the test construction waste soil (test construction waste soil). In some cases, the physical properties of the soil (including the case where several samples are sampled) are different from each other.

[0004] Therefore, when it is considered that there is a difference in the physical properties between the new construction waste soil and the test construction waste soil, it is necessary to start over from the first blending test and to examine the blending each time. The decision required a lot of time and effort.

[0005]

Means for Solving the Problems The present inventors have argued that the conventional daily method of blending control may be considered to reduce the simplicity, or that the test construction residual soil to be collected is collected from several places. It was also noted that there was only one kind of material having similar properties to the construction-generated residual soil to be improved, and that only the water content was the measurement item for the physical properties of the construction-generated residual soil to be improved.

[0006] A plurality of test soils with different physical properties having different properties are used to produce test soils of various compositions, and the relationship between the physical properties of the test soils and the physical properties of the test soil with improved physical properties is determined. It was thought that the number of tests would be increased if it was grasped, but that the overall time and labor required for determining the formulation would be reduced.

On the other hand, the development of the strength of a mixture of earth and sand, a solidifying agent and water is related to the content of fine earth particles in the earth and sand corresponding to fine aggregate, and the fluidity of the mixture is determined by the liquid of the earth and sand. It is known to be governed by sex limits. Based on this knowledge, we focused on the fact that the measurement items of the physical properties of the construction-generated residual soil at the time of determining the composition would not be sufficient with only the water content, and as a measurement item, the content ratio of fine soil particles in the soil, that is, We thought that adding the particle size distribution and the liquid property limit value of the earth and sand would determine the formulation that could be applied to the production of actual soil with improved physical properties. As a result of three items: water content, content ratio of fine soil particles, and liquid property limit value, there is almost no variation in the quality of the soil with improved physical properties when using construction-generated residual soil with the same physical properties, and this idea is correct. Has been established, and the present invention has been achieved.

That is, the invention according to claim 1 of the present application is based on the premise that "(A) physical properties of a plurality of types of construction-generated surplus soil,
By measuring both the physical properties of various types of test soils manufactured by mixing materials such as solidifying agents and water with this composition and the remaining soil in various combinations, data showing the relevance of the two properties can be obtained. Accumulating, and (B) measuring the physical properties of the construction-generated surplus soil to be improved, and determining the composition for improving the physical properties of the construction-generated surplus soil by comparing the physical properties with the accumulated data. A method for determining a composition for improving the physical properties of construction-generated surplus soil, characterized by comprising: The invention according to claim 2 is characterized in that the property measurement items of the construction-generated surplus soil to be improved include (1) water content, and (2) the content of fine soil particles under 75 μm obtained by measuring the specific gravity of the sedimenting soil slurry. Proportion, (3) 3 of liquid limit value by fall cone test
2. The physical properties of construction-generated surplus soil according to claim 1, wherein the measurement of (3) is omitted if the construction-generated surplus soil is determined to be sandy soil based on the measurement result of (2). To determine the formulation to improve ".

[0009] A large number of compounding tests with improved physical properties are performed by using various types of residual soil for test construction whose physical properties are measured, which is a feature of the invention according to claim 1, and a large amount of compounding test results are prepared and accumulated. In addition, the method of determining the composition of the soil with improved physical properties in comparison with the stored data on the physical properties of the target construction-generated surplus soil is based on a large amount of past data accumulated through numerous experiments. Although it may be common in the field of science (especially chemistry) as a method to solve various problems, it is a new method for construction waste soil.

[0010] The characteristics of the invention according to claim 2, that is, the measurement items of the physical properties of the construction residual soil are (1) water content, (2) the content ratio of fine soil particles under 75μm by measuring the specific gravity of the sedimentation soil slurry (3) There are three items of the liquid limit value by the fall cone test, and the measurement point (3) is omitted when the residual soil from construction is judged to be sandy soil based on the measurement result of (2). This is a particularly significant feature of the invention. Of course, the greater the number of measurement items, the more the accuracy of the blending test is improved. On the other hand, as the number of measurement items increases, the number of the blending tests increases exponentially, and the time and labor required for it increases. In the present invention, in order to improve the accuracy of the test with relatively few compounding tests,
The measurement items of the physical properties of the construction surplus soil were the above three items (1), (2) and (3).

This measurement item is increased by one item in the case of sandy soil and by two items in the case of cohesive soil as compared with the case where only the water content of the conventional method is used, and the measurement and the mixing test increase accordingly. . However, according to the conventional method, as described above, it is necessary to repeat from the first compounding test every time using construction-generated residual soil having different physical properties, and the time and labor required for the overall measurement and compounding test are rather reduced by the present invention. Is often smaller.

In the present invention, the following three methods are used to measure the water content ratio, the content ratio of fine soil particles under 75 μm by measuring the specific gravity of the settling soil slurry, and the liquid limit value by the fall cone test, as described below. A simple measuring method conforming thereto is adopted.

(A) Moisture content ratio JIS A 1203 (b) Content ratio of fine soil particles under 75 μm by measuring specific gravity of sedimenting soil slurry A simple measuring method described below (hereinafter referred to as a simple sedimentation method) is adopted. You.

Outline of the simple sedimentation method. (1) Construction of the sample The remaining soil generated is measured, put into a container containing an appropriate amount of water, and stirred to sufficiently disperse the remaining soil in water.

(2) Place the remaining soil water slurry in a graduated cylinder filled with water, and shake the graduated cylinder back and forth and around the bottom of the graduated cylinder, taking care not to spill it with the lid. . A measuring cylinder with a capacity of about 1 liter is used. The mixing ratio of water (total with water for dispersion) and residual soil is determined by preliminary experiments.
A certain value is selected within the range of ~ 980cc and the remaining soil of 60 ~ 200g.

(3) Hold the graduated cylinder for a certain time (usually 1
Minutes) After standing still, gently insert the hydrometer into the graduated cylinder, read the hydrometer after a certain period of time (usually 5 minutes) after inserting the hydrometer, read the value and the calibration curve prepared in advance. Thus, the content ratio of fine soil particles under 75 μm in the soil is determined. (The particle size distribution has been determined by a test based on the soil particle size test method of JIS A 1204, and the same operation was performed on several types of samples that differed in the content ratio of fine soil particles under 75 μm. Prepare a calibration curve in advance for the relationship between the content ratio of fine soil particles under 75 μm.) The specific gravity is measured under the same conditions for both the construction residual soil and the target construction residual soil for the blending test. Is natural. The value of the specific gravity is used as an index instead of the precise particle size distribution of the soil particles in the remaining soil. Although not quantitative, qualitatively the higher the value of the measured specific gravity, the greater the content of fine particles in the soil particles. As usual, those with a content ratio of fine soil particles below 75 μm of 15 to 50% are considered to be sandy soil, and those with 50% or more are considered to be cohesive soil. By adopting this simple sedimentation method, the measurement of the particle size distribution of the soil particles, which took a long time, can be completed in a short time of 10 minutes or less, and then it is possible to immediately proceed to the production of the soil with improved physical properties.

(C) Liquid limit value by fall cone test Geotechnical Society of Japan JSF T 141-1990 In measuring the liquid limit value by the fall cone test, the water content often changes during sample preparation.
And the measured liquid property limit value naturally has a correlation with the water content ratio. Therefore, in order to accurately measure the liquid limit value, it is necessary to minimize the change in the water content during sample preparation, but it is extremely difficult to completely avoid the change in the water content during sample preparation on site. Yes, not realistic. Therefore, at the time of sample preparation on site, water is added to the target soil to obtain a constant moisture content (for example, 100%), and the liquid limit value of this sample is measured, and the correlation between the known liquid limit value and the water content is determined. It is realistic and convenient to estimate the liquid property limit value of the soil with the actual water content by using it.

In the present invention, various soils of various physical properties are collected and used for a blending test.
There are few types of soil that are collected naturally, and in many cases, it is not possible to cover the remaining soil from construction that is expected to occur in the future. To address this, naturally collected soils, for example, those that are naturally collected by mixing a sandy soil with a small percentage of fine particles and a sandy soil with a high percentage of fine particles It is necessary to artificially synthesize soil having a different particle size distribution of soil particles, and to subject the synthesized soil to a compounding test.

In the case where the remaining soil is determined to be sandy soil by the measurement of the physical properties of the target construction residual soil, the accumulated mixing test results are immediately obtained without waiting for the measurement of the liquid limit value by the fall cone test. The composition of the soil with improved physical properties is determined, but if the target construction residual soil is determined to be cohesive soil, wait for the measurement of the liquid property limit value by the fall cone test and refer to the accumulated composition test results. The composition of the property improving soil is determined.

When the physical properties of the target construction residual soil completely match the physical properties of the soil subjected to the test, the composition of the soil with improved physical properties is immediately determined from the accumulated mixing test results. In many cases, the physical properties of the generated residual soil do not completely match the physical properties of the soil subjected to the compounding test. In this case, the blending ratio is determined by referring to the blending test results using test soils that are the same or similar in the order of the content ratio of the fine soil particles and the liquid property limit value. To adjust.

When waste mud is used as the compounding water, it has been confirmed that the dispersing agent contained in the mud does not adversely affect the quality of the soil with improved physical properties.
It is necessary to measure pH, viscosity (funnel viscosity), specific gravity, etc., to confirm that they match the muddy water used in the compounding test and that there is no limit on the amount of compounding.

In the present invention, it is preferable that the data accumulated by a large number of compounding tests be managed by a computer, and the necessary information be output immediately upon input of the measurement result of the target construction residual soil. Needless to say. In addition, a method of graphing the composition test results and determining the composition on the graph from the measurement result of the target construction residual soil is a preferable method that can be performed simply and in a short time.

[0023]

Embodiments of the present invention will be described below.

FIG. 1 is a flow chart for determining the composition of the soil with improved physical properties according to the present invention, and FIG. 2 is a diagram showing the physical properties of the residual soil generated from the test construction and the additives which can be used to produce soil with improved quality. (Accumulated material and water) was added to the data collected in the past.
3 is a graph summarizing the content ratio of the fine soil particles under m, and FIG. 3 is a graph similarly summarizing the data accumulated in the past with respect to the liquid limit value of the remaining soil after construction.

The suitability of the method for determining the composition of the soil with improved physical properties according to the present invention was tested on the three types of construction residual soil shown in Table 1 below. Since it is a compatibility test, various types of tests that are not adopted in actual on-site work are performed on three types of surplus soil generated during construction.

[0026]

[Table 1] The specific gravity of each residual soil measured by the simple sedimentation method was 1.010, 1.038 and 1.037, respectively, and the content ratio of fine soil particles under 75 μm was 28%, 86% and 98%, respectively.
%, The first sample was determined to be sandy soil, and the second and third samples were determined to be clayey soil.

The first sample, which was determined to be sandy soil, was inserted into a position where the content of fine soil particles under 75 μm in the graph of FIG. 2 was 28%, and the remaining soil, cement,
The amount of water was determined as shown in Table 2.

Since the second and third samples were determined to be clayey soils, the liquid limit values were further measured by a fall cone test, and the measured values were 65.5% and 103.0%, respectively. The measured values were fitted to the respective liquid property limit values in the graph of FIG. 3, and the amounts of generated residual soil, cement, and water were determined as shown in Table 2.

[0029]

[Table 2] The physical properties of the compounded physical properties improved soil are as shown in Table 2,
All of the flow, breathing, and uniaxial compressive strengths achieved the expected target values.

[0030]

According to the present invention, the types of surplus soil generated for the test are increased, and the measurement items of the surplus soil generated for the construction are 1 to 2 compared to the conventional method.
Although the number of items increases, it is not necessary to repeat from the first compounding test every time using construction waste soil having different physical properties as in the conventional method, and a highly reliable compounding can be determined. In addition, since the content ratio of fine soil particles under 75μm can be grasped by the simple sedimentation method without having to measure the particle size distribution of the generated residual soil by a strict test method, the formulation of the soil with improved physical properties can be determined in a short time as on-site work. can do.

[Brief description of the drawings]

FIG. 1 is a flowchart for determining the composition of a physical property improving soil of the present invention.

FIG. 2 shows the relationship between the physical properties of test-constructed surplus soil and the amounts of additives (solidification material and water) that can be used to produce good quality physical properties-improved soil. It is the graph which summarized the data about the content ratio of the fine soil particle of 75 micrometers or less of the residual soil generated by the test construction.

FIG. 3 shows the accumulated relationship between the physical properties of test-constructed surplus soil and the amounts of additives (solidification material and water) that can be used to produce good quality property-improved soil. It is the graph which put together the data about the liquid property limit value of construction residual soil.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) G01N 33/24 C09K 103: 00 // C09K 17/10 B09B 5/00 ZABF C09K 103: 00 M (72) Inventor Hidekazu Anai Kashima Construction Co., Ltd. 1-2-7 Moto Akasaka, Minato-ku, Tokyo (72) Inventor Satoshi Manabe Kashima Construction Co., Ltd. F-term (1-2-7 Moto-Akasaka, Minato-ku, Tokyo) Reference) 2D043 CA01 EA06 4D004 AA32 BA02 CA45 CC11 CC13 DA01 DA02 DA09 DA10 DA16 DA20 4H026 CA01 CC06

Claims (2)

[Claims] (A) The properties of a plurality of types of construction residual soil, and various types of test soils prepared by mixing materials such as a solidifying agent and water in various combinations with the construction residual soil in advance. And (B) measuring the physical properties of the construction-generated surplus soil to be improved and measuring the physical properties as described above. Determining the composition that improves the physical properties of the construction-generated surplus soil by comparing the data with the data. 2. The measurement items of the properties of the construction-generated surplus soil to be improved are (1) water content, (2) content ratio of fine soil particles under 75 μm obtained by measuring specific gravity of sedimentation slurry, and (3) fall cone. There are three items of the liquid limit value by the test, and the measurement of the above (3) is omitted when the construction residual soil is determined to be sandy soil based on the measurement result of the above (2). 2. A method for determining a composition for improving physical properties of construction-generated surplus soil according to 1.