JP2001354960A - Method for utilizing construction surplus soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, when poor soil such as soft soil is solidified with a slurry containing a setting material, the application range is extremely narrowed due the low strength of a solidified product to make practical applications difficult. SOLUTION: This method for utilizing construction surplus soil is shown for a case when it is applied to the earth to be refilled 14 for a sewer pipe 12 to be buried under the base course 10. Upon completion of placing the sewer pipe 12, the earth to be refilled 14 is filled in a ditch 16 so as to surround the periphery of the sewer pipe 12. The earth to be refilled 14 is prepared by adding a part of the construction surplus soil to the dug earth and sand generated at the execution site and agitating and mixing them with a slurry containing a setting material such as cement. The slurry has a water to cement ratio of less than 60% and is added with a retarded setting viscosity reducing agent and, at the same time, the setting material in an amount of >=4 KN per a unit volume.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for using construction excavated soil such as excavated earth and sand.

[0002]

2. Description of the Related Art Most of embankment materials used for building residential lands and roads, and embankment materials such as dams and embankments are soil materials. Such soil materials are usually procured at these construction sites. Have been.

[0003] In recent years, in the shield construction employed when constructing a subway tunnel in an urban area, excavated soil is generated when excavating the ground. Such excavated residual soil has various characteristics such as soft soil and good quality soil, and good quality soil is reused as landfill or embankment without improving its properties.

On the other hand, poor quality soil such as soft soil requires expensive disposal costs as industrial waste. Therefore, its properties are improved by adding and mixing a slurry containing a solidifying material such as cement or lime. It is considered that the soil may be reused as landfill or embankment. However, such a method of using construction residual soil has the following technical problems.

[0005]

That is, when solidified poor soil such as soft soil is solidified with a slurry containing a solidifying material, the strength of the solidified material is low, so its application range is very narrow, and practical use is difficult. There is a problem that the application becomes difficult.

In this case, in order to achieve high strength, for example, there is a method of increasing the amount of solidified material of the slurry. However, when the amount of solidified material is increased, the viscosity of the slurry increases, and when the pressure of the slurry is increased, In addition to the deterioration of the workability, other problems such as the non-uniformity of the properties of the solidified body arise.

[0007] The present invention has been made in view of such conventional problems, and an object of the present invention is to prevent construction work from deteriorating and expand the applicable range thereof. The purpose of this is to provide a method of use.

[0008]

In order to achieve the above object, the present invention relates to a method for mixing and stirring a construction waste soil such as excavated earth and sand and a slurry containing a solidifying material such as cement, and mixing the construction waste soil with the slurry. Solidified by the backfill, the backfill soil when constructing underground structures such as sewage pipes and box culverts, backfill soil behind retaining walls, invert filling materials for shield tunnels, foundation works for permanent structures such as tanks and buildings, dams In the method of using construction surplus soil as permanent landfill or embankment such as embankment materials for embankments or embankments, the slurry is set such that the water-cement ratio is set to less than 60% and a slow-setting viscosity reducing agent is added. did. According to the utilization method of the construction surplus soil configured in this way, a permanent landfill or embankment produced by mixing and stirring the construction surplus soil such as excavated earth and sand and a slurry containing cement, and solidifying the construction surplus soil with the slurry, The water-cement ratio of the slurry is set to less than 60%. In this case, when a solidifying material of 4 KN or more per unit volume is added at the same time, the strength per unit area is increased, and the applicable range is expanded. Further, when the water-cement ratio of the slurry is set to less than 60%, there is a concern that the viscosity of the slurry is increased, the workability is reduced, the mixing becomes uneven, and the properties of the solidified body are not stable. In this case, since the slow-hardening viscosity reducing agent is added to the slurry, it is possible to avoid a decrease in workability due to an increase in viscosity and an unevenness of the solidified body. More specifically, the water-cement ratio of the slurry can be set to 40%, which is less than 60%. The addition amount of the slow-hardening viscosity reducing agent can be set so that the viscosity of the slurry becomes 2000 CP or less. According to this configuration, it is possible to secure workability equivalent to that of the conventional method in which the water-cement ratio of the slurry is about 60%. From the above, in the present invention, a solidified body having higher strength and uniformity than before can be produced. Further, by adding reinforcing fibers, it is possible to impart toughness to the solidified body.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG.
1 shows a first embodiment of a method for utilizing construction surplus soil according to the present invention. The method of using the remaining construction soil shown in FIG. 1 is applied to a backfill soil 14 at the time of constructing an underground structure 12 such as a sewer pipe buried under a roadbed 10.

The underground structure 12 is formed by excavating a groove 16 having a predetermined width under the roadbed 10 by an open-cutting method or the like.
6 on the bottom surface. When the installation of the underground structure 12 is completed, the trench 16 is filled with backfill soil 14 so as to surround the outer periphery thereof. When the filled backfill soil 14 solidifies, the construction is completely completed.

In this case, the backfill soil 14 is produced by partially adding construction surplus soil, slag, and the like to excavated earth and sand generated at a construction site, and mixing and mixing these with a slurry containing a solidifying material such as cement. You.

[0012] As the construction surplus soil, for example, ground excavation surplus soil generated at another construction site, construction waste soil generated by dismantling a concrete structure, or the like can be used. When using construction waste soil, it is preferable to crush concrete lump and the like to adjust the particle size. In addition, as long as the excavated earth and sand generated at a construction site is sufficient by itself, for example, the excavated earth and sand may be used alone, or the construction waste earth may be used alone.

The slurry to be mixed with the surplus construction soil has a water-cement ratio of less than 60%, a slow-setting viscosity reducing agent added, and a solidified material of 4 KN or more per unit volume. ing.

When the slurry having such a structure is used, the water-cement ratio is set to less than 60%, and the solidified material is added at 4 KN or more per unit volume. Strength is high and uniform.

In this case, the water-cement ratio of the slurry is 60
%, There is a concern that the viscosity of the slurry is increased, the workability is reduced when the slurry is pumped, the mixing is not uniform, and the solidified body is not stable. In this case, since the slow-hardening viscosity reducing agent is added to the slurry, it is possible to avoid a decrease in workability due to an increase in viscosity and an unevenness of the solidified body.

For example, the amount of the slow-setting viscosity reducing agent can be set so that the viscosity of the solidified material becomes 2000 CP or less after about one hour of standing time. As is clear from a viscosity test described later, workability equivalent to that of the conventional method in which the water-cement ratio of the slurry is about 60% can be secured.

Also, as in this embodiment, the underground structure 12
When used as the backfill soil 14 above, the structure 12 is a lightweight, high-strength, and highly uniform backfill material for the structure 12, so that the number of members constituting the structure 12 can be reduced. This is possible, which is advantageous in terms of economy.

Conventional backfill materials, such as construction surplus soil,
In the case of mountain sand, it is uneven and requires compaction, and the unit weight is large. In the case of fluidized soil, compaction is not necessary, but the strength is inferior to the present invention.

In the case of the foam mortar, although it is lightweight, there is a problem peculiar to each material such as its workability, in particular, the problem with water. A similar use can achieve the required objectives while avoiding the problems of conventional backfill materials.

FIG. 2 shows a second embodiment of the method for utilizing construction surplus soil according to the present invention. The method of using the construction surplus soil shown in the figure is a case where the present invention is applied to the backfill soil 14a filled in the upper part of the tunnel 18.

In this case, the backfill soil 14 a
In the same manner as in the embodiment, a part of construction excavated soil slag is added to excavated soil generated at the construction site, and the mixture is stirred and mixed with a slurry containing a solidifying material such as cement.

The slurry mixed with the surplus soil and the like has a water-cement ratio of less than 60%, a slow-setting viscosity reducing agent is added, and a solidifying material is added at 4 KN or more per unit volume.

When the present invention is applied to such backfill soil 14a, in addition to the effect of the above embodiment, when the backfill soil 14a is solidified, the overload applied to the tunnel 18 can be reduced.

FIG. 3 shows a third embodiment of the method for utilizing construction surplus soil according to the present invention. The method of using the construction surplus soil shown in FIG.
2 is a case where the present invention is applied.

In this case, as in the first embodiment, the backfill soil 22 is obtained by adding a part of construction excavated soil and slag to the excavated soil generated at the construction site, and mixing them with a slurry containing a solidifying material such as cement. It is produced by stirring and mixing.

The slurry mixed with the surplus construction soil has a water-cement ratio of less than 60%, a slow-setting viscosity reducing agent added, and a solidified material of 4 KN or more per unit volume.

When the present invention is applied to such backfill soil 22, in addition to the operation and effect of the above embodiment, when the backfill soil 22 is solidified, the side pressure applied to the retaining wall 20 can be reduced.

FIG. 4 shows a fourth embodiment of the method for utilizing construction surplus soil according to the present invention. The method of using the surplus construction soil shown in the figure is a case where the present invention is applied to the invert filling material 28 of the shield tunnel 26 defined by the segment 24.

In this case, as in the first embodiment, the invert filling material 28 is obtained by adding a part of the remaining construction soil and slag to the excavated soil generated at the construction site, and mixing them with a slurry containing a solidifying material such as cement. It is produced by stirring and mixing.

The slurry to be mixed with the construction waste soil and the like has a water-cement ratio of less than 60%, a slow-setting viscosity reducing agent is added, and a solidifying material is added at 4 KN or more per unit volume.

When the present invention is applied to such an invert filling material 28, the excavated soil generated in the shield work can be effectively used, and the amount of industrial waste can be greatly reduced.

FIG. 5 shows a fifth embodiment of the method for utilizing construction surplus soil according to the present invention. The method of using the remaining construction soil shown in FIG. 1 is a case where the present invention is applied to the foundation work 32 of the building 30.

The foundation work 32 is similar to the first embodiment,
It is manufactured by adding a part of construction residual soil and slag to excavated soil generated at the construction site, and stirring and mixing these with a slurry containing a solidifying material such as cement.

The slurry to be mixed with the surplus construction soil has a water-cement ratio of less than 60%, a slow-setting viscosity reducing agent added, and a solidifying material of 4 KN or more per unit volume. Even when applied to such a foundation work 32, the same operation and effect as the above embodiment can be obtained.

FIG. 6 shows a sixth embodiment of the method for utilizing construction surplus soil according to the present invention. The method of using the construction surplus soil shown in the figure is a case where the present invention is applied to the embankment material 36 such as a dam or an embankment.

The embankment material 36 is obtained by adding a part of construction excavated soil and slag to excavated soil generated at the construction site and stirring and mixing these with a slurry containing a solidifying material such as cement, as in the first embodiment. It is produced by

The slurry to be mixed with the construction waste soil and the like has a water-cement ratio of less than 60%, a slow-setting viscosity reducing agent is added, and a solidifying material is added at 4 KN or more per unit volume. Even when applied to such an embankment material 36, the same operation and effect as the above embodiment can be obtained.

FIG. 7 shows a seventh embodiment of the method for utilizing construction surplus soil according to the present invention. The method of using the construction surplus soil shown in the figure is a case where the present invention is applied to the embankment material 38 of the low embankment or the high embankment.

The embankment material 38 is obtained by adding a part of construction excavated soil and slag to excavated soil generated at the construction site and stirring and mixing these with a slurry containing a solidifying material such as cement, as in the first embodiment. It is produced by

The slurry to be mixed with the surplus construction soil has a water cement ratio of less than 60%, a slow-setting viscosity reducing agent added, and a solidifying material of 4 KN or more per unit volume. Even when applied to such embankment material 38, the same operation and effect as in the above embodiment can be obtained.

In this embodiment, the characteristics of the high-strength embankment material 38 are utilized to effectively utilize the land boundary without performing slope protection in the case of low embankment. Embankment becomes possible.

Further, in the case of high embankment, embankment utilizing the land boundary effectively can be performed by performing simple slope protection work. Further, since there is no need for compaction unlike the conventional embankment method, there is no ground subsidence due to compaction of the embankment portion, and high quality embankment can be achieved.

FIGS. 8 to 10 show the results of experiments conducted to confirm the effects of the present invention. 8 and 9 show the results of a strength test of the solidified body using a slurry having a water cement ratio of 40%. FIG. 8 shows a material age of 28 days, and FIG. 9 shows a uniaxial compression of a material age of 90 days. It is a measurement result of intensity.

In the strength test of the solidified body, as a solidified material,
. JIS R5210 ordinary Portland cement (N
),. JIS R5211 blast furnace cement type B (referred to as BB),. Cement-based solidifying material 1 (manufactured by Sumitomo Osaka Cement Co., Ltd., Tough Lock B, trade name, referred to as TLB),. Cement-based solidifying material 2 (manufactured by Taiheiyo Cement Corporation, Geoset 23, trade name, referred to as GS23),. Cement-based solidifying material 3 (manufactured by Taiheiyo Cement Corporation, Geoset new, trade name, GS new),.
Cement-based solidifying material 4 (manufactured by Ube Mitsubishi Cement Co., Ltd., Eustavir 30, trade name, US30);
Cement-based solidifying material 5 (manufactured by Taiheiyo Cement Corporation, Geoset A, trade name, referred to as GSA); Cement-based solidifying material 6 (manufactured by Taiheiyo Cement Corporation, Geoset B,
Eight types were prepared.

In the present embodiment, what is referred to as a cement-based solidifying material is a general term for a mixture of cement, a pozzolanic substance such as slag and fly ash, and an inorganic compound such as sulfuric acid and calcium chloride. It is.

The soil material corresponding to the construction surplus soil is. sand,
. Silt,. clay,. Four types of ROHM were prepared.

The added amount of each solidifying material was 5.0 KN / m ³ , and the water cement ratio was 40%. Then, an 18N slow hardening viscosity reducing agent (proto powder, trade name, manufactured by Mitsubishi Rayon Co., Ltd.) was added to each slurry.

The preparation of the specimen is in accordance with JGS T821 "Method of preparing specimen without compaction of stabilized soil", and the strength test is based on JIS A1216 "Method of uniaxial compression test of soil".
Performed in accordance with

As is clear from the results of the strength tests shown in FIGS. 8 and 9, except for the loam,
It was confirmed that a uniaxial compressive strength of 10 N / mm ² or more was obtained by selecting a solidifying material for each of sand, silt, and clay.

The magnitude of the uniaxial compressive strength is 0.1 to 0.4 N / mm in the onshore construction in the conventional deep mixing method.
^2, a value of more than 2 times the design strength, which has been a 0.5~2.5N / mm ² at sea construction, also, the design strength criteria for high-pressure injection mixing method, the sandy soil 1.0 ~ 3.0 N / m
It was confirmed that both values were larger than m ² and 1.0 N / mm ² of the cohesive soil.

FIG. 10 shows the results of measuring the change over time in viscosity when a slow-setting viscosity reducing agent is added to a slurry containing a solidifying material such as cement used in the method of use of the present invention. .

In this viscosity test, proto powder (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) was used as a slow-setting viscosity reducing agent.

As a solidifying material of the slurry, ordinary Portland cement was used, and the water cement ratio was set to 40%. The addition amount of the slow setting viscosity reducing agent was set as shown in the following table. In this viscosity test, for comparison, the viscosity of the slurry to which the slow-setting viscosity reducing agent was not added was also measured.

[0054]

[Table 1]

Each slurry was prepared using a cement mixer with the composition shown in Table 1, and the stirring time was 3 minutes. Then, the viscosity was measured with a B-type viscometer over time.

FIG. 10 shows the results of the viscosity test. As is clear from the results shown in FIG. 10, when the proto powder was added within the range of 0.05 to 0.10 KN / m ³ , the water-cement ratio was reduced. It was found that even at 40%, the viscosity of the slurry was about 2000 CP after about 1 hour of standing time.

The viscosity of about 2000 CP is shown in FIG.
The water-cement ratio without addition of the slow-setting viscosity reducing agent is the same as that of a 60% slurry, and the water-cement ratio is set to 60 to 120% in the standard specification of the indoor mixing test of the conventional deep mixing method. Within the range
When the viscosity is about 2000 CP, the water cement ratio becomes 6
It was confirmed that the same workability as in the case of 0% can be secured.

It can be said from the above test results that when the slurry is mixed and stirred with various kinds of soil and the soil is solidified with the slurry, even if the water-cement ratio of the slurry is less than 60%, the slow-setting viscosity reducing agent is used. By adding an appropriate amount of, the strength per unit area when solidified can be increased without lowering the workability.

Accordingly, the backfill soil 14 of the underground structure 12 such as a sewer pipe or a box culvert, the backfill soil 22 on the back of the retaining wall 20, the invert filling material 28 of the shield tunnel 26, and the permanent structure such as a tank and a building. Foundation work 32,
It is possible to greatly expand the applicable range of the method of using construction residual soil as permanent landfill or embankment, such as embankment material 36 for dams and embankments.

[0060]

As described above in detail in the embodiments,
ADVANTAGE OF THE INVENTION According to the utilization method of the construction residual soil which concerns on this invention, a fall of workability and the nonuniformity of solidified body can be expanded, and an applicable range can be expanded.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a first embodiment of a method for utilizing construction surplus soil according to the present invention.

FIG. 2 is an explanatory cross-sectional view showing a second embodiment of the method of using construction surplus soil according to the present invention.

FIG. 3 is an explanatory sectional view showing a third embodiment of the method of using construction surplus soil according to the present invention.

FIG. 4 is an explanatory cross-sectional view showing a fourth embodiment of the method for utilizing construction surplus soil according to the present invention.

FIG. 5 is an explanatory cross-sectional view showing a fifth embodiment of the method for utilizing construction surplus soil according to the present invention.

FIG. 6 is an explanatory cross-sectional view showing a sixth embodiment of the method for utilizing construction surplus soil according to the present invention.

FIG. 7 is an explanatory sectional view showing a seventh embodiment of the method for using construction surplus soil according to the present invention.

FIG. 8 is a graph showing measured values of uniaxial compressive strength at a material age of 28 days when a slurry used in the method for utilizing construction residual soil according to the present invention is applied to various types of soil.

FIG. 9 is a graph showing measured values of uniaxial compressive strength at a material age of 90 days when a slurry used in the method for utilizing construction residual soil according to the present invention is applied to various types of soil.

FIG. 10 is a graph showing a measured value of a change over time in viscosity when a slow setting viscosity reducing agent is added to a slurry used in the method for utilizing construction residual soil according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Roadbed 12 Sewer pipe 14 Backfill soil 18 Tunnel 20 Retaining wall 22 Backfill soil 24 Segment 26 Shield tunnel 28 Invert filling soil

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) E21D 11/00 C09K 103: 00 // C09K 103: 00 B09B 3/00 ZAB (72) Inventor Hiroshi Wada Tokyo 2-15-2 Konan, Minato-ku, Tokyo Obayashi Gumi Main Office (72) Inventor Nobunaga Ino 2-1-2-2 Konan, Minato-ku, Tokyo Obayashi Gumi Main Office (72) Inventor Noriaki Tanaka Konan, Minato-ku, Tokyo 2-15-2 Obayashi Gumi Main Office (72) Inventor Fumiyuki Yokomizo 2-152-2 Konan, Minato-ku, Tokyo (72) Inventor Hiroyuki Nishigami 2-Chome Konan, Minato-ku, Tokyo 15-2 Obayashi Gumi Inc. (72) Inventor Yoshimi Hosoya 2-1-2 Konan, Minato-ku, Tokyo 2-15 Obayashi Gumi Inc. (72) Inventor Tatsuyuki Matsuo Kiyose, Tokyo Shimokiyoto 4-640 Co., Ltd. large forest sets Institute of Technology in the F-term (reference) 2D018 AA01 2D043 CA01 CA20 EA06 2D055 BA01 BB01 BB03 CA08 KA11 4D004 AA32 BA02 CA15 CA45 CB26 CC03 CC13 DA02 DA03 DA09 DA20 4H026 CA01 CC03 CC06

Claims (3)

[Claims] 1. An underground structure such as a sewer pipe or a box culvert is constructed by mixing and agitating construction residual soil such as excavated earth and sand and a slurry containing a solidifying material such as cement to solidify the construction residual soil with the slurry. Permanent landfill or embankment such as backfill soil at the time, backfill soil behind the retaining wall, invert filling material for shield tunnels, foundation works for permanent structures such as tanks and buildings, and embankment materials such as dams and embankments In the method for using construction surplus soil, the slurry includes setting a water-cement ratio to less than 60% and adding a slow-setting viscosity reducing agent. 2. The slurry has a water-cement ratio of 40%.
The method according to claim 1, wherein the method is set to: 3. The use of construction surplus soil according to claim 1, wherein the amount of the slow setting viscosity reducing agent is set so that the viscosity of the slurry is 2,000 CP or less after about one hour of standing time. Method.