JP4574386B2 - Mixing method of solidifying material in improved soil and mixing method of solidifying material and auxiliary in improved soil - Google Patents

Description

  The present invention relates to “a method of blending solidified material in improved soil” and “a method of blending solidified material and auxiliary agent in improved soil” used in construction and other fields, and more specifically, the amount of solidified material and auxiliary agent added to the soil material The present invention relates to a method for obtaining an improved soil having an excellent property by appropriately adjusting.

“Soil” is generated by the weathering and fine-graining of rocks and the influence of living things. In civil engineering, “soil” refers to a combination of particulate matter (soil particles, etc.) that constitutes the surface of the earth and three phases (air, water, organic matter) that coexist therewith. Density (unit volume weight), porosity ratio, moisture content, saturation (ratio of water in the soil gap), consistency (soil condition depending on the moisture content), compaction characteristics, shear characteristics Is indispensable to know the mechanical properties of "soil". The term “soil” is sometimes used to describe the engineering properties, state, and type of “soil”. In addition, “soil” of various soil types used for construction and other purposes is sometimes referred to as “soil material”. In addition, gravel, coarse sand, fine sand, silt and clay belonging to “soil particles” are widely known to have the following properties (1) to (5).
(1) Gravel = more than 2mm in particle size. Weak activity. Holds little water.
(2) Coarse sand = particle size 0.425-2.0mm
Contributes to soil skeleton formation. Large interparticle pores. Promotes ventilation and drainage.
(3) Fine sand = particle size 0.075-0.425mm
Each particle separates. There is no stickiness or cohesion.
(4) Silt (fine sand) = particle size 0.005-0.075mm
The coarse part plays a skeletal role, and the fine part contributes to the physicochemical reaction. It is not sticky but has a slight cohesion.
(5) Clay = particle size less than 0.005 mm Large surface area. Contributes to physicochemical reactions such as water surface adsorption and ion exchange. High tackiness and cohesion.

As is generally the case in other fields, soil materials used in the construction field have different characteristics required for different uses. Referring to the embankment embankment material for this, in the case of blade soil (peeled soil), cone index 500 kN / m ² , air porosity 15%, permeability coefficient 1 × 10 ⁻⁵ cm / s or less, effective adhesive strength 20 kN / m ² and an effective internal friction angle of 28 ° are required. In the case of clay (plow soil), the cone index and the air porosity are the same as described above, the hydraulic conductivity is 1 × 10 ⁻⁵ to 1 × 10 ⁻⁴ cm / s, the effective adhesive force is 15 kN / m ² , and the effective internal friction angle. 30 ° is required. Further, in the case of sheath soil (soil soil), the cone index and the air porosity are the same as described above, the water permeability is 1 × 10 ⁻⁴ to 1 × 10 ⁻² cm / s, the effective adhesive force is 10 kN / m ² , and the effective internal friction. An angle of 35 ° is required. Therefore, for the levee body, a soil material suitable for each application is made by blending raw materials, and the object is built using the material.

  On the other hand, the characteristics of soil materials depend on the raw materials. By the way, low-quality soil used in the construction field not only has poor workability, but it is difficult to finish the work as designed. Therefore, bad soil is processed into improved soil. However, if the soil quality is inferior, the processing technology burden, labor burden, cost burden, etc. for soil improvement will increase, and it will not be possible to easily obtain a material that satisfies the requirements. In particular, recently, we have improved and used locally generated soil (on-site generated soil) from the viewpoint of environmental protection and economic efficiency. Effective measures are needed.

Invention of the following patent document 1 is a technique of removing and removing the bottom mud deposited and accumulated in the basin so that it can be used as a banking material, and repairing or reinforcing the basin dam body using it. The steps of this literature technique are as follows. First, the solidified material is added to the bottom sediment of the pond and mixed with stirring to make a mixture. Next, the mixture is left for a predetermined curing period, and a solidified mixture is formed by this curing. After that, the solidified mixture is excavated with a backhoe or the like, and the excavated solidified mixture lump is crushed into a predetermined size (particle size) with a crusher to produce a crushed piece. The crushed pieces thus obtained are transported to the embankment embankment and used as embankment material.
JP 2000-248538 A Fill dam filling with mudstone (Sadahiro Shiromoto et al.) Mie Prefectural Government Office, Yamamura Dam Construction Technology Vol.10 No.3 pp.12-19 (1977) Strength characteristics of crushed treated soil (Osamu Kawanabe et al.) 17th Geotechnical Engineering Conference 262-16-224 (1982) Investigation on properties of construction sludge, Part 2 Results of solidification test (Yukio Tasaka et al.) 30th Geotechnical Engineering Conference, pp. 233-3234 (1995) Basic research on the use of construction sludge improved soil, part 1 Difference in strength characteristics by various solidifying materials (Kazushiki Seki et al.) 30th soil engineering research presentation, pages 221-2222 (1995) Fundamental study on the use of construction sludge improved soil-Part 2 Laboratory experiments assuming recycling process (Tatsuhiko Sato et al.) 30th Geotechnical Engineering Conference 222-22-2224 (1995) Basic research on the use of construction sludge improved soil-Part 3 Strength characteristics (Katsu Fujisaki et al.) 30th soil engineering research presentation, pages 225-2226 (1995) Basic research on the use of construction sludge improved soil, part 4 Correlation of strength indicators (Kyoyo Kuno et al.) 30th Geotechnical Engineering Conference, pp. 2227-2228 (1995) Basic research on utilization of construction sludge improved soil, Part 5 Compaction characteristics (Hiraki Saruwatari et al.) 30th Geotechnical Engineering Conference 2229-2230 (1995) Fundamental Study on Utilization of Construction Sludge Improved Soil, Part 6 Shear-Consolidation Characteristics (Akihiko Sato et al.) 31st Geotechnical Research Conference 199-200 (1996) Basic research on utilization of construction sludge improved soil, Part 7 Over compaction characteristics (Sayaka Shimizu et al.) 31st Geotechnical Research Conference 299-300 (1996) Fundamental study on utilization of soil improved with construction sludge Part 8 Swelling-strength characteristics under water immersion conditions (Katsufuji Fujisaki et al.) 31st Geotechnical Research Conference 301-302 (1996) Fundamental study on utilization of soil improved with construction sludge Part 9 Change in properties due to repeated drying and wetting (Katsuhiko Yokoyama et al.) 31st Geotechnical Research Conference 303-304 (1996) Fundamental Study on Recycling of Construction Sludge Improved Soil-Part 10 Strength Characteristics of Different Types of Construction Sludge Improved Soil (Yasuo Tasaka et al.) 31st Geotechnical Research Presentation 305-306 (1996) Fundamental study on utilization of construction sludge improved soil, Part 11 Strength characteristics by lime-based improved materials (Kyoyo Kuno et al.) 31st Geotechnical Research Conference 307-308 (1996) Basic study on utilization of construction sludge improved soil Part 12 Grasp of alkali elution from improved soil (Toshihiko Nakamura et al.) 31st Geotechnical Research Presentation 309-310 (1996) Fundamental study on the use of construction sludge improved soil Part 13 Study on soil alkali adsorption capacity (Fumihiro Baba et al.) 31st Geotechnical Research Conference 291-292 (1996) Fundamental Study on Utilization of Construction Sludge Improved Soil, Part 14 Effects on Planting (Yasuyuki Sakamoto et al.) 31st Geotechnical Research Presentation 293-294 (1996) Concept and technology development for recycling and recycling construction sludge (Nobuyoshi Ogawa et al.) 31st Geotechnical Engineering Conference 297-298 (1996) Fundamental study on utilization of construction sludge improved soil Part 15 Solidification characteristics of cement and lime based improved materials (Yukio Tasaka et al.) 32nd Geotechnical Research Conference 89-90 (1997) Fundamental Study on Recycling of Construction Sludge Improved Soil, Part 16 Strength Characteristics of Reconsolidated Construction Sludge Improved Soil (Takuya Honma et al.) The 32nd Geotechnical Research Conference 91-92 (1997) Fundamental study on utilization of construction sludge improved soil, Part 17 Uniaxial compressive strength-Evaluation of improved soil inundation degradation characteristics by continuous needle penetration test, 32nd Geotechnical Research Conference 93-94 (1997) Basic Study on Use of Construction Sludge Improved Soil, Part 19 pH Change over Time of Improved Soil Infiltrated Water (Kazuyuki Yoshikawa et al.) 32nd Geotechnical Research Conference 97-98 (1997) Strength characteristics of improved and compacted construction soil (Takahiro Otsuki et al.) The 32nd Geotechnical Research Conference 2417-2418 (1997) Consideration on compaction of improved construction soil (Katsu Fujisaki et al.) The 32nd Geotechnical Research Conference 2419-2420 (1997) Strength characteristics of solidified crushed soil (Atsuko Sato et al.) 32nd Geotechnical Research Conference 2423-2424 (1997) Strength characteristics of solidified crushed soil, part 2 (Atsuko Sato et al.) 33rd Geotechnical Research Conference, pages 2291-2292 (1998) Use of construction sludge for embankment (general professional from the Ministry of Construction) Foundation work (Hiroyuki Yamamoto) Vol.26 No.11 pp. 58-63 (1998) New irrigation pond rehabilitation method (Tanishige) Agricultural Civil Engineering Vol.68 No.12 90-91 (2000) Ministry of Agriculture, Forestry and Fisheries, Structural Improvement Bureau, Construction Department Design Section: Land Improvement Project Design Guidelines “Reservoir Maintenance” Agricultural Civil Society of Japan (2000) Study on applicability of pond bottom mud to embankment material after solidification treatment (Shinji Fukushima, Shigeru Tani et al.) Journal of Japan Society of Civil Engineers No.666 III-53 99-116 (2000) Field verification test for confirming applicability of pond bottom mud to embankment embankment material after solidification (Shinji Fukushima, Shigeru Tani et al.) No.680 III-55 pages 269-284 (2001) Rehabilitation method using solid mud in aged pond (Shinji Fukushima, Shigeru Tani et al.) Soil and foundation Vol.50 No.11 36-38 (2002) No.715 III-60 pp.165-178 (2002) No.715 III-60 pp.165-178 (2002) Target strength setting / mixing test method and construction management method for embankment soil obtained by crushing and rolling solidified bottom mud An example of repair of an old pond body using solid mud soil (Shinji Fukushima, Shigeru Tani et al.) Soil and foundation Vol.51 No.11 5-7 (2003) Rehabilitation method using bottom mud in old irrigation pond and its application (Tanishige, Shinji Fukushima et al.) Water and soil No.135 84-93 (2003) No.750 III-65 pages 205-221 (2003) No.750 III-65 205-221 (2003) Cement-based solidification material ground improvement manual, third edition Cement Association (2003) Soil compaction and management (Division of Geotechnical Engineering) Soil Basic Engineering Library 36 Compaction management Quality control method / Air porosity method 177-178 (1991) Phildam Technical Notes / Materials and Basics and Practice (Fumio Uto) Nikkan Kogyo Shimbun, p. 51 (1979) Research Committee on Physical and Mechanical Properties of Cement Stabilized Soil Symposium on Cement Stabilized Soil Japan Geotechnical Society (August 1996)

  When using the technique of Patent Document 1, the bottom mud deposited in the reservoir can be applied to the bank embankment material. This means that it is possible to recover the function of the pond by securing the bottom mud (to secure water storage capacity and to purify water quality) and to renovate and reinforce the dam body without acquiring land for the acquisition of embankment materials. . Therefore, the invention of Patent Document 1 is a technique that is useful for the construction of a basin where sediment is deposited, and also a technique that can simultaneously solve the problem of local use of the generated soil.

  However, although patent document 1 is disclosing about the solidification material addition rate of a padding embankment and a presser embankment, it does not disclose the solidification material addition rate regarding the whole embankment material including embankment and sheath soil. Therefore, a technique for optimally setting the solidifying material addition rate when making various improved soils is desired. In this kind of technical field, it is also important to establish such a technology early because it is necessary to produce an improved soil having a constant characteristic with no excess or deficiency in the amount of solidifying material added. In addition, the generated soil is not limited to bottom sediment mud. For example, construction generated soil (type 1 construction generated soil-type 4 construction generated soil) and construction sludge (such as mud-like excavated materials, mud and mud) resulting from excavation work can be added by adding solidification material without excess or deficiency. Solidification material addition technology is indispensable for making improved soil suitable for various uses.

  On the other hand, the technologies reported or disclosed in Non-Patent Documents 1 to 40 have many contents that can be referred to and can be referred to without being within the scope of the results. Further research and development are desired to provide promising technologies that can be used.

  The present invention has been made in view of such problems. In other words, the present invention relates to the compounding technology of the solidified material in the improved soil, such as the uniaxial compressive strength, the cone index, the air porosity, the water permeability, the effective adhesive force, and the effective internal friction angle in consideration of the compaction energy. It is intended to provide a method that can be set rationally in relation to the solidification material addition rate, and further to provide a blending method of a solidification material and an auxiliary agent that can achieve the same purpose more economically. .

  The blending method of the solidified material in the improved soil described in claim 1 of the present invention is characterized by the following problem solving means in order to achieve the intended purpose. That is, the method for blending the solidifying material in the improved soil according to claim 1 is to prepare a plurality of specimens having different blending ratios of the soil material and the solidifying material for the specimen using the soil material and the solidifying material as main raw materials. Obtaining the correlation between the uniaxial compressive strength of the prepared specimen and the solidification material addition rate, and compacting each loosened specimen, and the cone index, air porosity, and hydraulic conductivity of the compacted specimen・ Determine one or more of effective adhesive strength and effective internal friction angle, obtain correlation between uniaxial compressive strength and compaction energy of the compacted specimen, and compact with the set compaction energy When creating an improved soil where one or more of the cone index, air porosity, hydraulic conductivity, effective adhesive strength, and effective internal friction angle are finished as intended, One axis corresponding to the set compaction energy with reference to one or more of the cone index, air porosity, hydraulic conductivity, effective adhesive force, and effective internal friction angle of the above compacted specimen equal to the target value of the selected item The compressive strength is selected from the correlation between the uniaxial compressive strength of the compacted specimen and the compaction energy, and the solidification material addition rate corresponding to the selected uniaxial compressive strength is determined as the uniaxial compressive strength of the specimen. The selection is based on the correlation with the solidification material addition rate, and a predetermined amount of solidification material is added to the soil material based on the selected solidification material addition rate.

  The method for blending solidified material in the improved soil according to claim 2 of the present invention is the method according to claim 1, wherein when the consistency index of the soil material is -0.46 or less, the powdered solidified material is used as the soil material. When the consistency index of the soil material is −0.46 or more, a slurry-like solidification material of [water / solidification material = 1] is added to the soil material.

  The blending method of the solidifying material and the auxiliary agent in the improved soil described in claim 3 of the present invention is characterized by the following problem solving means in order to achieve the intended purpose. That is, the blending method of the solidifying material and auxiliary agent in the improved soil according to claim 3 is characterized in that an auxiliary agent for improving strength is added to the improved soil obtained by the method according to claim 1 or 2.

The blending method of the solidifying material in the improved soil of the present invention is that the improved soil has at least one selected from a cone index, an air porosity, a water permeability coefficient, an effective adhesive force, and an effective internal friction angle and a uniaxial compressive strength. Since it is satisfactory, it has the following effects.
(1) Important data for satisfying the conditions for improved soil is obtained in advance using a specimen, and a predetermined amount of solidification material based on the data is added to the soil material to create improved soil with the required characteristics. The solidifying material for the soil material in this case is accurately added based on data obtained in advance in order to ensure the required improved soil characteristics. Therefore, improved soil with high reliability can be obtained in relation to the required properties.
(2) Since the required improved soil characteristics can be satisfied with the minimum amount of solidifying material added, there is no waste of solidifying material. Since this also reflects the cost, the improved soil can be manufactured inexpensively and reasonably.
(3) About various improved soils with two or more characteristics, those with different characteristics can be made depending on the amount of solidification material added. Accordingly, not only those satisfying the minimum requirements from the viewpoint of characteristics, but also improved soils with higher characteristics can be easily produced by preparing the solidified material. This also means that it is easy to obtain an improved soil having characteristics depending on the application.
(4) Since the solidified material in the form of powder or the solidified material in the form of slurry is used according to the consistency index of the soil material, various necessary soil materials with different properties and conditions are reasonably improved. Can be finished in soil.
(5) As long as the specifications of the improved soil are determined, it can be carried out at any site, including on-site production that can be adapted to the local site (on-site) and production that can be stocked in a yard. Therefore, the flexibility in producing improved soil is high.
(6) Defective soil, which had to be disposed of at a high cost, can be improved into high-quality useful materials, and such materials become valuable resources. This eliminates bad soil disposal on the one hand, and on the other hand gains valuable resources by switching from minus to plus, so it has great environmental impact reduction and economic value.
(7) Since only the solidification material is added to the soil material and mixed, the equipment burden for producing the improved soil is light and the operation energy is small. Therefore, both initial cost and running cost can be kept low.

The blending method of the solidifying material and the auxiliary agent in the improved soil of the present invention uses the method of the above invention, so that the same effect as described above can be obtained, but there are other effects as follows.
(8) It is difficult to improve strength and characteristics without excess and deficiency in a single treatment for a wide variety of soil materials. Incidentally, when the strength is insufficient, the soil material must be reprocessed while adding the solidifying material, and when the strength is excessive, the use amount of the solidifying material is increased. In particular, when unraveling with improved cutting soil using a cutting blade, the strength tends to be insufficient. In such a case, the strength deficiency is compensated by adding an auxiliary agent for improving the strength to the soil material (improved soil) that has been improved by the addition of the solidifying material. This is also an advantageous means for producing improved soil because it leads to the relaxation of strength setting in the prior treatment (addition of solidifying material) and simplification of the processing work associated therewith, and also prevents excessive use of the solidifying material. Become. Of course, a cost push factor can be avoided by using an auxiliary agent that is less expensive than the solidified material.

  An embodiment of the method for blending solidified material in the improved soil according to the present invention will be described below based on experimental results and attached drawings.

  In the method of the present invention, an improved soil is produced by adding a solidifying material to a soil material. The soil material in this case includes the above-mentioned “soil” in terms of civil engineering. Speaking of higher-level concepts, various materials such as natural (natural), artificial, or a mixture of them correspond to soil materials. Thus, among the soil materials, there are various soil "soils" that can be used in the construction and other fields. Specifically, some of the soil materials are sandy soil, clay, silt, cohesive volcanic ash, organic soil, sludge, sludge, and a mixture of two or more of these. For solidification materials, cement-based solidification materials, lime-based solidification materials, granulated slag fine powder, neutral solidification materials (solidification materials that do not elute high alkali), neutral solidification improvement materials (solidification components, agglomeration components, water content ratio adjustment) Components), neutralization and solidification improvers (solidification component, coagulation component, moisture content adjustment component, pH adjustment component). Typical examples of cement-based solidifying materials used for soil improvement include ordinary Portland cement, blast furnace cement, special soil cement (colloid cement and ultra-fast cement), and mixed cements thereof.

  First, a plurality of specimens, for example, three types of specimens having different blending ratios between the soil material and the solidifying material are prepared for the specimens mainly composed of the soil material and the solidifying material. A specific example in this case is as follows. Next, the physical properties and chemical properties of each specimen are measured as follows.

[Preparation of specimen]
As the soil material, pond sedimentary mud collected from the field (pond bottom sedimentary mud) and / or imitated material is used. Cement-based “Blast Furnace Cement Type B” is used as the solidifying material. One reason for using this solidified material is that latent hydraulic properties due to blast furnace granulated slag can be expected, and the elution amount of hexavalent chromium is below the reference value.
(1) Prior to the blending test, the mud is thoroughly stirred in advance and the wet density and moisture content of the mud are measured. The following can be said from the results of physical and chemical property tests on pond bottom mud. From the result of the loss on ignition of 16.6%, it is judged that the organic substance is contained considerably. The reason why the natural water content ratio is as large as about 300% is considered to be attributed to the contained organic matter. The ground material is classified as organic clay. For other reasons, the natural water content of the pond mud is in the range of 12 to 240%, whereas the water content of the pond bottom mud is about 300%. The clay content is 65.9%, which is about twice as much as the silt content, and is all fine particles (0.074 mm or less). It is not easy to reduce the water content ratio from the natural water content ratio of about 300% to the plastic limit (53.7%). The elution of heavy metals is considered to be satisfactory because all items in the Environmental Agency Notification No. 46 (1991) satisfy the environmental standard values.
(2) Addition rate of solidifying material to soil material is 50-200%, and a predetermined amount of cement slurry with W / C = 1 is added to the dry weight of the mud, and stirred for about 5 minutes with a hand mixer. Mix. At this time, the turn-back is twice. This makes three types of initial improved soils for specimens with different solidification material addition rates.
(3) Put the improved soil for the specimen into an acrylic resin mold with a diameter of 5 cm and a height of 12.5 cm.
(4) Strike the mold 50 times against the concrete floor so that no air bubbles get in.
(5) The upper end surface of the mold is sealed with a synthetic resin wrapping film, and the initial improved soil is cured for 7 days in a temperature-controlled room at a temperature of 20 ° C. and a humidity of 95%.

[Uniaxial compression test of initial improved soil]
After the 7-day curing, the initial improved soil, that is, the 7th-age specimen, is removed from the mold, and subjected to a uniaxial compression test in accordance with JIS-A-1216.・ Measure dry density and uniaxial compressive strength.

[Setting of initial improvement strength as index]
An initial improvement strength (q _u7 ) _serving as an index is set with reference to known or well-known technical contents. Here for each _specimen, and ^{_{q u7 = 125kN / m 2,}} q u7 = 246kN / m 2, q u7 = 369kN / m 2.

[Determination of solidification material addition rate]
For each specimen, it determines a _{^{q u7 = 125kN / m 2,}} q u7 = 246kN / m 2, q u7 = 369kN / m 2 and solidified material addition rate corresponding to the relationship uniaxial compressive strength and solidifying material addition rate.

[Unraveling the initial improved soil]
Unravel each specimen with a straight edge and use it as a loose soil. Sometimes the maximum particle size of the loosening soil is set to 1/5 or less of the mold diameter so as not to cause significant variation in the compaction density and the strength characteristics of the prepared specimen. The particle size range is set as follows in consideration of the uniaxial compressive strength of the initial improved soil and the satisfactory hydraulic conductivity.
Initial improved soil of q _u7 = 125 kN / m ² → target particle size 0 to 9.5 mm (blade soil)
Initial improved soil with q _u7 = 246 kN / m ² → target particle size 4.75 to 9.5 mm (sheath soil)
Initial improved soil of q _u7 = 369 kN / m ² → target particle size 4.75 to 9.5 mm (burrow)

[Tokihashi soil compaction]
The initial improved soil which has been loosened is placed in two layers in an iron split mold having a diameter of 5 cm and a height of 10 cm, and then a 1.525 kg of rammer is dropped from a height of 20 cm to each layer and compacted. The number of compaction is 0 times / layer, 1 time / layer, 3 times / layer, 6 times / layer for each specimen (the compaction energy Ec is 0 kJ / m ³ , 31 kJ / m ³ , 92 kJ / m, respectively) ³ and 183 kJ / m ³ ), and measurement items are wet density, water content ratio, and dry density. The same compaction energy as the tamping method A in the standard compaction test (JIS-A-1210) is Ec = 550 kJ / m ³ (the number of compactions is 18 times / layer) when the mold is used.

[Cone index test of compacted soil]
The loosened initial improved soil is divided into two layers in an iron split mold similar to the above, and is tamped by means similar to the above compaction. The number of tamping (consolidation) and the tamping (consolidation) energy Ec are the same as the above-mentioned compaction. A corn index test is performed on each compacted improved soil according to JIS-A-1228. Since various tests must be performed in a limited sample, the mold size is 5 cm in diameter and 10 cm in height. For the 10cm diameter x 12.73cm mold and 5cm diameter x 10cm mold (iron split mold) used in JIS-A-1228, the correlation of the cone index (qc) is confirmed in advance. Correct. Measurement items are wet density, water content ratio, and dry density.

[Permeability test of tough and compacted soil]
The loose specimen (improved soil on the 7th day of material age) is divided into two layers in a mold having a diameter of 10 cm and a height of 12.73 cm, and this is statically compressed to a sample height of 5 cm. At this time, with respect to a specimen having a diameter of 10 cm and a height of 5 cm, the wet density at the time of compaction (0 times / layer, 1 / layer, 3 times / layer, 6 times / layer) is obtained. Adjust the compression force. The material age of the specimen is the above 7th day, but the material subjected to the water permeability test shall be after the material age 28th. The water permeability test method conforms to JIS-A-1218, and uses a constant water level and a variable water level depending on the assumed water permeability coefficient.

[Triaxial compression test for compacted clay (consolidation undrained, pore water pressure measurement)]
In the same manner as above, the loosening soil is compacted, and it is divided into two layers in an iron split mold having a diameter of 5 cm and a height of 10 cm in the same manner as the cone index test, and each layer has a 1.525 kg rammer. Is dropped from a height of 20 cm and hardened. Tamped number also similar to paragraphs 0022 and each specimen with zero / layers, once / layer, 3 times / layer, 6 times / layer (compaction energy Ec, respectively ^{0kJ / m 3, 31kJ / m} 3 92 kJ / m ³ , 183 kJ / m ³ ). Here, the material age of the specimen is 7 days, but the water permeability test is after the material age 28 days. The test is performed in accordance with JIS-0523, soil compaction undrained, pore water pressure measurement, triaxial compression test method. The test conditions are as follows.
(1) The specimen is saturated by the double negative pressure method, and further saturated by applying a back pressure of 100 kN / m ² . Drain paper is wrapped around the side of the specimen to improve drainage during compaction.
(2) Confirmation of the saturation state of the specimen shall be B value = 0.95 or more (B value = increase in pore water pressure / increase in restraint pressure).
(3) isotropic consolidation stress for ^specimens, to ^{25kN / m 2, 50N / m} 2, 100kN / m 2.
(4) After pore water pressure dissipation, the shear rate of the specimen shall be 0.1% / min.

[When unraveling with a crusher]
The crusher shown in FIGS. 1 and 2 has a crushing chamber 21 having a diameter of about 1 m, crushing blades 41 having 1 to 6 stages, and crushing blades 41 having a number of (6 stages) × (8 / Stage) = 48 pieces / max, and the rotational speed of the crushing blade 41 is 0 to 1200 rpm. Each blade 41 is shaped like a double-edged sword, and has a straight knife edge 42 at the double-edged portion. 1 and 2, 11 is a support base, 12 is a base, 13 is a frame, 15 is an electric motor (motor), 16 is a transmission system, 17 is a driving pulley of the transmission system 16, and 18 is a transmission pulley 16. A driven pulley, 19 is a belt of the transmission system 16, 22 is an inlet of the crushing chamber 21, 23 is an outlet of the crushing chamber 21, 31 and 32 are a pair of upper and lower bearings, 33 is a stay, 35 is a rotating shaft, and 36 is a rotating shaft 35. , 37 is a mounting portion of the cutting blade 41, 38 is a pipe of a gas supply system for supplying hot air or hot air, 51 is a connector for attaching the cutting blade 41 to the rotary shaft 35, 61 Denotes a carry-in system (belt conveyor) for the object to be treated (improved soil), and 62 denotes a carry-out system (belt conveyor) for the loosening object.

  One of the specimens used for the occasional unraveling test consists of an early improvement soil on the 7th day of age, made from pond bottom sedimentary mud. One of the specimens to be subjected to the occasional unraveling test consists of an early improvement soil on the 7th day of the age, which was made using simulated mud soil (clay sand with a water content w = 100%) similar to the pond bottom sediment mud. . By the way, this clay sand is a clay product that is made by improving Kibushi clay used for porcelain for civil engineering.

In the crusher shown in FIGS. 1 and 2, when the belt conveyor type carrying-in system 61, the electric motor (motor) 15, the belt conveyor type carrying-out system 62, etc. are in an operating state, the specimen is loosened as follows. The carrying-in system 61 feeds the specimen into the crushing chamber 21 through the inlet 22 of the crushing chamber 21 while conveying the specimen. In the crushing chamber 21, the rotating shaft 35 and each of the plurality of radial blades 41 provided on the rotating shaft 35 are rotated at a high speed by receiving power transmitted from the electric motor 15. Specifically, when the soil material is a specimen made of pond bottom sedimentary mud, the _sample with q _u7 = 250 kN / m ² is set to 600 rpm, and the _sample with q _u7 = 350 kN / m ² is set to 750 rpm. When the soil material is a specimen made of clay sand, three samples of q _u7 = 150 kN / m ² are set to 450 rpm, 750 rpm, and 1050 rpm. However, since only the lower four blades 41 are used, the other blades are removed. The block-shaped specimen put into the crushing chamber 21 is unraveled by being cut by each blade 41 during high-speed horizontal rotation from the inlet 22 to the outlet 23. That is, about 70 to 90% of the whole is loosened to about 10 to 150 cm in diameter, and the rest is loosened to about 10 cm or less. FIG. 3 schematically shows this cutting situation. In the improved soil (specimen) 71 with reference to FIG. 3, a large number of soil particles 72 are bonded with a weak force through the solidifying material particles 73, and moisture 74 is held in the gaps between the soil particles 72. ing. The blade 41 during high-speed horizontal rotation exhibits a sharp sharpness with respect to the improved soil 71, and only the blade passing portion is cut and cut. Therefore, a situation does not occur in which each soil particle 72 is dispersed apart and a large amount of pore water flows out, or the outflow pore water and the dispersed soil particles are re-disturbed and softened. When the loosening soil reaches the outlet 23 of the crushing chamber 21 after the treatment, it falls onto the carry-out system 62. While being transported to a predetermined place through the carry-out system 62, the unraveling soil is dried by receiving warm or hot air (air-drying), and then screened and screened for particle size confirmation.

  Next, the test results of the initial improved soil using mud soil as the soil material and cement as the solidifying material will be described with reference to Table 1.

The symbols in Table 1 are as follows. P1 indicates the amount (unit kg / m ³ ) of the solidified material to be added on an external basis with respect to 1 m ³ of mud in a natural wet state. P2 is a percentage (unit%) of the ratio of the mass of solidified material added in an extra split to the wet mass of the mud to be improved. P3 is the percentage (unit%) of the ratio of the mass of solidified material added on a split basis to the dry mass of the mud to be improved. Wc indicates the amount of solidification material added per 1 m ³ of dried improved soil.

Expressions (01) to (03) in Table 1 relate to P1, P3, and Wc, respectively, and are as follows.
(01) Formula P1 = 10 × ρtn × P2 (kg / m ³ )
(02) Formula P3 = P2 × (1 + wn / 100)
= (1 + wn / 100) × P1 / (10 × ρtn)
(03) Formula Wc = 1000 × ρd × P3 / (100 + P3) (kg / m ³ )
In the above formula, ρtn is the wet density (g / cm ³ ) of the mud, wn is the moisture content (%) of the mud, and ρd is the dry density (g / cm ³ ) of the improved soil.

The mass of 1 m ³ of mud in the natural wet state is as follows.
1 m × 1 m × 1 m × ρtn (t / m ³ ) × 1000 = 1000 ρtn (kg)
From the definition of P1, the following equation can be derived.
P1 = 1000 × ρtn × (P2 / 100) = 10 × ρtn × P2
The following formula can be derived from the definition of P3.
P3 = P2 × (1 + wn / 100) = (1 + wn / 100) × P2
= (1 + wn / 100) × P1 / (10 × ρtn)
Therefore, P3 is expressed by the following equation (04).
(04) Formula P3 = 100 × Wc / Ws

The dry density ρd of the improved soil is as follows.
ρd = (Ws + Wc) / V = (Ws + Wc) / (1 × 1 × 1) = Ws + Wc
As for Ws, the following equation can be derived from equation (04).
Ws = 100 × Wc / P3
Further, Wc is expressed by the following equation (05) from the following equation regarding ρd.
ρd = (100 × Wc / P3) + Wc = Wc × (100 + P3) / P3
(05) Formula Wc = ρd × P3 × 1000 / (100 + P3) (kg)

FIG. 4 shows the relationship between the uniaxial compressive strength of the initial improved soil (material age 7 days) and the solidifying material addition rate P3 (%) based on the indoor blending test in Table 1 and the results thereof. The following contents could be considered from FIG.
(1) Although the uniaxial compressive strength increases as the solidification material addition rate increases, the uniaxial compressive strength is smaller than ordinary clay soil because mud contains a lot of organic matter.
(2) It is judged that the correlation is good although the uniaxial compressive strength slightly varies in the range of the solidification material addition rate of 150 to 200%.
(3) the intensity _q u7 ⁼ _{125kN /} m ² as an _{^{index, q u7 = 246kN / m 2}} , q u7 = 369kN / solidifying material addition rate P3 corresponding to ^{m 2,} P3 = 105%, respectively, P3 = 145%, P3 = 175%.

FIG. 5 shows the particle size distribution of the sample when the initial improved soil is loosened with a straight edge. The following matters were found from FIG.
(1) Each sample loosened with a straight edge has a bladed earth: a maximum particle size of 19.0 mm, a soil holding: a maximum particle size of 19.0 mm, and a sheath soil: a maximum particle size of 19.0 mm.
(2) For soil loosening when setting intensity is _q u7 = _125kN / ^{m 2,} for a target particle size range was _0～9.5Mm, unfolding of q u7 = 246kN / ^{m 2} and _q u7 = _369kN / ^{m 2} The passing mass percentage with a particle size of 4.75 mm or less is larger than that of the soil.

  Table 2 shows the uniaxial compressive strength of the initial improved soil and the cone index test result of the loosely compacted soil (the cone index is a corrected value).

  FIG. 6 shows the correlation between the cone index of a [diameter 10 cm × height 12.73 cm] mold used in [JIS-A-1228] and a [diameter 5 cm × height 10 cm] mold. It is. Referring to FIG. 6, the cone index of a mold having a diameter of 5 cm and a height of 10 cm is affected by the side wall due to the small mold diameter, and the mold having a diameter of 10 cm and a height of 12.73 cm. It became larger than the corn index.

FIG. 7 shows a plot of the relationship between the uniaxial compressive strength of the initial improved soil and the cone index of the loosely compacted soil for each compaction energy. The following contents could be considered from FIG.
(1) As the uniaxial compressive strength of the initial improved soil increases, the cone index increases.
(2) As the compaction energy Ec increases as Ec = 0 kJ / m ³ , Ec = 31 kJ / m ³ , Ec = 92 kJ / m ³ , Ec = 183 kJ / m ³ , the slope of the straight line increases. When the energy reaches Ec = 550 kJ / m ³ , it becomes slightly smaller. Visual observation shows that the loosening soil is twisted at 550 kJ / m ³ .

Table 3 shows the results obtained for each compaction energy for the uniaxial compressive strength of the initial improved soil where the cone index q _{c7 of the} loosely compacted soil is 500 kN / m ² .

FIG. 8 shows the relationship between compaction energy and uniaxial compressive strength of the initial improved soil. Further referring to FIG. 8, the relationship between compaction energy and uniaxial compressive strength of the initial improved soil is depicted based on Table 3. In FIG. 8, the shaded area corresponds to a region where the cone index q _c7 > 500 kN / m ² . The following contents could be considered from FIG.
(1) If the strength of the initial improved soil is large, q _c7 = 500 kN / m ² can be satisfied even with a small compaction energy. However, when the strength is small, it is necessary to increase the compaction energy.
_{(2) q c7 = 500kN /} m 2 minimum intensity of the initial modified soil which satisfies is generally determined that _q u7 = _170kN / ^{m 2.}

FIG. 9 shows the relationship between compaction energy and air porosity. The following contents could be considered from FIG.
(1) The air porosity decreases as the compaction energy increases. Even with the same compaction energy, the air porosity varies depending on the uniaxial compressive strength of the initial improved soil.
(2) The air porosity is considered to be asymptotic to 2 to 3% in each sample because particle crushing occurs when the compaction energy increases.
(3) When considering the degree of compaction related to the stability of the embankment in the same manner as the mudstone embankment material for crushing particles, the air porosity is Va <15% (Non-patent Document 38). Therefore, when the uniaxial compressive strength of the initial improved soil is 125 KN / m ² , the compaction energy Ec becomes Ec = 30 kJ / m ³ or more, and when the uniaxial compressive strength of the initial improved soil is 246 KN / m ² When the energy Ec is Ec = 76 kJ / m ³ or more and the uniaxial compressive strength of the initial improved soil is 369 KN / m ² , the compaction energy Ec is required to be Ec = 110 kJ / m ³ or more. The results are shown in Table 4.

Table 5 shows the water permeability test results of the loosely compacted soil.

FIG. 10 shows the relationship between the compaction energy and the hydraulic conductivity of the loose compaction soil. The following contents could be considered from FIG.
(1) When the compaction energy is small, the hydraulic conductivity is 1-2 × 10 ⁻³ cm / s regardless of the magnitude of the initial improved soil uniaxial compressive strength. Becomes smaller and the water barrier is increased.
(2) The curve varies depending on the uniaxial compressive strength of the improved soil.
(3) When the compaction energy is increased, the water permeability coefficient tends to be asymptotic to about 4 × 10 ⁻⁶ cm / s. This phenomenon is thought to be caused by particle crushing
(4) For each of the curves in FIG. 10, the permeability coefficient k = 1 × 10 ⁻³ cm / s, the permeability coefficient k = 1 × 10 ⁻⁴ cm / s, and the permeability coefficient k = 1 × 10 ⁻⁵ cm / s are satisfied. Table 6 shows the compaction energy.

  Table 7 shows the results of the triaxial compression test. In other words, this is the result of a triaxial compression test on the compacted undrained soil. Incidentally, soil compaction non-drainage refers to shearing while measuring pore water pressure in a non-drainage state after consolidation.

FIG. 11 shows the relationship between the uniaxial compressive strength of the initial improved soil and the effective internal friction angle. The following contents could be considered from FIG.
(1) The effective internal friction angle φ ′ is in the range of φ ′ = 30 to 40 °, and a certain tendency is recognized as in the case of non-unraveling cement stabilized soil (Non-patent Document 40) and Non-Patent Document 2. It is done. (2) Regardless of the uniaxial compressive strength of the initial improved soil, it is judged that almost the required effective internal friction angle φ ′ is obtained.

FIG. 12 shows the relationship between the uniaxial compressive strength of the initial improved soil and the effective adhesive strength. The following contents could be considered from FIG.
(1) It is recognized that the effective adhesive strength c ′ tends to increase as the uniaxial compressive strength of the initial improved soil increases (Non-Patent Documents 2 and 40).
(2) _With regard to the uniaxial compressive strength q _u7 of the initial improved soil, the required effectiveness is required when Ec = 31 kJ / m ³ , Ec = 92 kJ / m ³ and Ec = 183 kJ / m ³ when q _u7 = 125 kN / m ² The adhesive strength c ′ is not obtained.
(3) Table 8 shows the uniaxial compressive strength at which the effective adhesive force c ′ = 20 kN / m ² and each compaction energy Ec (kJ / m ³ ) intersect.

  Table 14 shows the results of the unraveling test for the initial improved soil using the crusher shown in FIGS.

Further, FIG. 13 shows the particle size accumulation curve of the loosening soil, and FIG. 14 shows the relationship between the compaction energy and the Talbot-type index n (Non-patent Document 39) representing the particle size curve. The following contents could be considered from FIG.
(1) The Talbot equation for expressing the particle size accumulation curve is as shown in the following equation (06), and this is the particle size distribution that is most compacted when the index n is in the range of 0.25 to 0.5. It is said to show. In the Talbot formula, when the index n becomes smaller, the fine particle portion becomes larger, and when the index n becomes larger, the fine particle portion becomes smaller (Non-patent Document 39).
(06) Formula P = (d / Dmax) ⁿ × 100 (%)
In the above formula, P is the mass percentage (%) through which the material passes, d is the particle size (mm) of the material, Dmax is the maximum particle size (mm) of the material, and n is an index.
(2) The Talbot index n decreases with the increase in the rotation speed of the blade 41 in the crusher. Further, as the strength of the initial improved soil increases, the Talbot index n tends to decrease.
(3) The crusher is determined to be able to produce loosening soil at an arbitrary particle size distribution by changing the rotation speed, the number of blade stages, and the number of blades. Further, even if hard stones or gravel are contained in the improved soil, the blade 41 operates flexibly, so that it does not hinder the operation.
(4) The points to keep in mind when loosening the improved soil with a crusher are not to twist using an edge-type blade, to select the rotation speed within an appropriate range, and to reduce the maximum particle size, set the number of blade stages. It is good to increase.

Among the matters described so far, the relationship between the uniaxial compressive strength of the initial improved soil and the cone index of the loosely compacted soil (Fig. 7), the relationship between the compaction energy and the uniaxial compressive strength of the initial improved soil (Fig. 8) Relationship between compaction energy and air gap curve (Fig. 9), relationship between compaction energy and permeability of tough compaction soil (Fig. 10), uniaxial compressive strength of initial improved soil and effective internal friction angle 15 (FIG. 11), the relationship between the uniaxial compressive strength of the initial improved soil and the effective adhesive force (FIG. 12), the results of the compaction energy and the uniaxial compressive strength of the initial improved soil shown in FIG. Organized into a relationship. Incidentally, the hatched portion in FIG. 15 is a region satisfying the cone index q _u7 = 500 kN / m ² . In FIG. 15, the boundary lines satisfying the design values (water permeability coefficient [k], strength constant [c ′, φ ′]) of each embankment material are indicated by alternate long and short dash lines, and the air porosity is used as the embankment compaction management reference value. A boundary line satisfying Va is indicated by a broken line. The following contents could be considered from FIG.
(1) As for the uniaxial compressive strength of the initial improved soil that satisfies the design values required for each embankment material, the range in which the cone index q _u7 = 500 kN / m ² or more of the loosely compacted soil is obtained in FIG. And the water permeability coefficient k and the air porosity Va from a range that satisfies the three requirements.
(2) As for the shear strength constant, both the effective adhesive force c ′ and the effective internal friction angle φ ′ should be satisfied as long as the cone index of the _loosely compacted soil satisfies q _u7 = 500 kN / m ² or more. Can do. That is, as long as the cone index is satisfied, the shear strength constant can be satisfied.
(3) Cone index q _u7 = 500 kN / m ² , uniaxial compressive strength q _{u7 of} initial improved soil satisfying water permeability coefficient k, shear strength constants c ′, φ ′, air porosity Va and compaction energy at that time The results obtained for Ec are as follows.
In the case of bladed earth → q _u7 = 170 kN / m ² Ec = 183 kJ / m ³
In the case of embedment → q _u7 = 210 kN / m ² Ec = 105 kJ / m ³
In the case of sheath soil: q _u7 = 250 kN / m ² Ec = 80 kJ / m ³
(4) From the relationship between the solidification material (cement) addition rate and the uniaxial compressive strength of the initial improved soil in FIG. 4, the solidification material addition rate P3 (%) required for each embankment material is as follows.
In the case of bladed earth → P3 = 120%
In case of embedment → P3 = 135%
In case of sheath soil → P3 = 148%
(5) Table 10 shows the results of obtaining P1 (unit kg / m ³ ), P2 (unit percentage%), and Wc (unit kg / m ³ ). These P1, P2, and Wc are as described above, P1 is the mass of the solidified material (cement) added in an external ratio to 1 m ³ of wet natural mud, and P2 is external to the wet mass of improved mud. The ratio of the mass of solidified material (cement) added by splitting, Wc is the amount of solidified material (cement) added per 1 m ³ of the dried improved soil. Incidentally, Wc dry density of the initial modified soil which was used to obtain the (kg / ^{m 3),} the blade Fri Sat 0.50 T / ^{m 3,}抱土0.51t / ^{m 3,} the sheath earth 0.52t / ^{m 3} It is.

The above-mentioned contents are based on past literature surveys on the applicability of improving mud soil deposited on the pond bottom with a solidification material (cement), unraveling the improved soil, and using it as a dam body embankment material. This was confirmed by a blending test. Based on this, the results shown in Table 11 were obtained. The following contents were considered from the above results.
(1) Due to the test mud sampled from the surface layer, the amount of solidified material (cement) added to it is extremely large. Since the mud deposited in the pond has different water content and particle size composition both in terms of position and depth (Non-Patent Document 31), it is important to investigate the average water content and particle size composition and conduct an indoor blending test. It is.
(2) In order to reduce the amount of solidifying material (for example, cement) added, it is necessary to reduce the addition of powder or the ratio [W / C] of “water: cement” or q _u28 / q _u7 ≒ 1.5 It is desirable to take a long curing period using (e.g., improve with a cement-based solidified material each time in the previous year, and then unload and fill in every two years).

表１１において、泥土は有機質粘土で自然含水比が約３００％と高いものである。これは粉体混合が困難なため、セメント添加はＷ／Ｃ＝１のスラリーで添加している。さらにセメントとしては、材料コストが最も安価で、六価クロムの溶出量が少なく、長期強度増加が期待できる高炉Ｂを用いている。

In Table 11, mud is organic clay and has a high natural water content of about 300%. Since it is difficult to mix the powder, cement is added as a slurry of W / C = 1. Further, as the cement, a blast furnace B is used which has the lowest material cost, has a small amount of hexavalent chromium elution, and can be expected to increase in long-term strength.

  The method of the present invention is clear from the above description. That is, the method of the present invention satisfies one or more selected from a cone index, an air porosity, and a water permeability and uniaxial compressive strength when making an improved soil using a solidified material and a soil material as raw materials. When making the improved soil, the matter to satisfy the condition is obtained in the specimen, and a predetermined amount of solidification material is added to the soil material based on the solidification material addition rate selected with reference to it. . Therefore, the method of the present invention can be applied to various applications as long as the solidified material is added to the soil material to produce improved soil satisfying the above two predetermined conditions.

  By the way, when the sedimentary mud in the basin is improved by the method of the present invention and the dam body is repaired or reinforced using the improved soil, the water falling in the pond (falling step) → in-situ mixing (mixing step) → in-situ Curing of improved soil (curing step) → Excavation and transport (excavation-transport step) → Unraveling when improving soil (toki unraveling step) → Transporting to embankment (transporting step) → Spreading and leveling (spreading and leveling) Step) → consolidation (consolidation step) and the like.

  Each step in the above is as follows. In the falling water step, pond water is extracted by a known means. In the mixing step, for example, cement-based solidified material is added to the sedimentary mud in the pond, and the mixture is uniformly mixed with a trencher type stirring machine or the like. The solidification material addition rate with respect to the mud at this time differs depending on what the improved soil is used for and what values the uniaxial compressive strength and compaction energy are. In the case of the improved soil for the sheath soil, the sheath soil region of FIG. 15 is used. In the case of the improved soil for the holding soil, the soil region of FIG. 15 is used. The region may be referred to, and the solidification material addition rate corresponding to the uniaxial compressive strength at that time may be read from FIG. 4 to add a predetermined amount of the solidification material to the sedimentary mud. During the curing step, the state after the addition of the solidifying material is maintained, and waiting for a predetermined date and time to elapse. As an example, the curing period is 7 days. The excavation-transport step is carried out using a backhoe or rubber crawler carrier. At the time of the unraveling step, the crushing machine described with reference to FIGS. 1 and 2 is used. The transporting step is carried out using a dump truck, the spreading-laying step is carried out using a wetland bulldozer or the like, and the compacting step is carried out using a wetland bulldozer, a normal bulldozer, a tire roller or the like.

What is necessary is just to select the aspect of the solidification material used in the above according to the consistency index Ic of the soil material shown to a following formula. Incidentally, when the Ic of the soil material is −0.46 or less, it is preferable to use a powdered solidified material. Conversely, when the Ic of the soil material is −0.46 or more, [water (w) / solidified material]. It is preferable to use a slurry-like solidified material of (c) = 1]. With respect to the relative relationship between the powdery solidified material and the slurry-like solidified material, a greater strength can be obtained with the powdery solidified material if the addition ratio is the same.
Ic = (W _L −W) / (W _L −W _P ) = (W _L −W) / I _P
W _L : Liquid limit W _P : Plastic limit W: Natural water content or given water content I _P : Plasticity index

  When the strength of the improved soil obtained by the above-mentioned solidifying material combination is lower than the target value or when the strength of the improved soil is increased in accordance with the change of the strength setting value, the strength of the improved soil is increased. You can loosen this by adding the auxiliary. In such a case, the means shown in FIG. 1 and FIG.

  The above-mentioned auxiliary agents include gravelly soil, paper sludge incinerated ash, natural polymer polymer, synthetic polymer polymer, coal ash, porous material, concrete crushed fine particles, gypsum-based solidified material, cement-based solidified material, and lime-based solidified material. -Shells, natural minerals, iron powder, activated carbon, etc. Therefore, the auxiliary agent may be used alone or in combination of any two or more. The amount of the auxiliary agent added to the improved soil is selected within the range of 0.001 to 20% with respect to the wet soil weight.

  One of the soil materials mentioned in the above embodiment is pond bottom sedimentary mud, but it is clear from the above description that the pond bottom sedimentary mud is only an example of soil material. As another example of mud-based soil materials, mud-like excavated materials, mud water, mud and the like resulting from excavation work are also within the scope of application of the method of the present invention. Therefore, these are also finished into a promising improved soil by adding a solidifying material and / or an auxiliary agent according to the above-described contents.

  The method of the present invention is based on the improved soil that depends on the solidifying material and auxiliary agent, and the uniaxial compressive strength, the cone index, the air porosity, the water permeability, the effective adhesive force, the effective internal friction angle, taking into account the compaction energy. It is highly useful in construction and other fields because it can be reasonably obtained to satisfy the requirements as required.

It is the longitudinal cross-sectional view which showed schematically an example of the crushing means used by one Embodiment of this invention method. FIG. 2 is a cross-sectional view schematically showing the crushing means of FIG. 1. It is sectional drawing which showed typically the cutting condition of the improved soil in the method of this invention. It is the graph which showed the relationship between the solidification material addition rate in the method of this invention, and the uniaxial compressive strength of initial improvement soil. It is the graph which showed the particle size distribution when initial improvement soil is loosened with a straight edge in one Embodiment of this invention method. It is the graph which showed the result of having drawn the cone index correlation of two molds from which specification differs in one Embodiment of this invention method. It is the graph which showed the relationship between the uniaxial compressive strength of initial improvement soil, and the cone index of a loose compaction soil in one Embodiment of this invention method. It is the graph which showed the relationship between compaction energy and uniaxial compressive strength of initial improvement soil in one Embodiment of this invention method. It is the graph which showed the relationship between compaction energy and air porosity in one Embodiment of this invention method. It is the graph which showed the relationship between the compaction energy in one embodiment of this invention method, and the hydraulic conductivity of the loosening compaction soil. It is the graph which showed the relationship between the uniaxial compressive strength of initial improvement soil, and an effective internal friction angle in one Embodiment of this invention method. It is the graph which showed the relationship between the uniaxial compressive strength of initial improvement soil, and effective adhesive force in one Embodiment of this invention method. It is the graph which showed the particle size accumulation curve of the loosening clay in one Embodiment of this invention method. It is the graph which showed the relationship between the compaction energy and the Talbot type | formula index | exponent showing a particle size curve in one Embodiment of this invention method. It is the graph which showed the relationship between compaction energy and uniaxial compressive strength of initial improvement soil in one Embodiment of this invention method.

Explanation of symbols

41 Crushing blade 71 Improved soil 72 Soil particles 73 Solidification material particles

Claims (3)

  For specimens mainly composed of soil material and solidification material, several specimens with different mixing ratios of soil material and solidification material were prepared, and the correlation between the uniaxial compressive strength of the prepared specimen and the solidification material addition rate Obtaining the relationship and compacting each loose specimen, and one or more of the cone index, air porosity, hydraulic conductivity, effective adhesive force, and effective internal friction angle of the compacted specimen In addition to obtaining the correlation between the uniaxial compressive strength and the compaction energy of the compacted specimen, and by compacting with the set compaction energy, the cone index, air porosity, hydraulic conductivity, effective adhesive strength, and effective When creating an improved soil where one or more of the internal friction angles are finished as intended, the cone index of the compacted specimen equal to the target value of the selected item Referring to one or more of air porosity, hydraulic conductivity, effective adhesive force, and effective internal friction angle, the uniaxial compressive strength corresponding to the set compaction energy is determined according to the uniaxial compressive strength and compaction of the compacted specimen. Select from the correlation with energy, and select the solidification material addition rate corresponding to the selected uniaxial compression strength from the correlation between the uniaxial compression strength of the specimen and the solidification material addition rate, and selection A method for blending solidifying material in improved soil, wherein a predetermined amount of solidifying material is added to the soil material based on the solidified material addition rate.   When the consistency index of the soil material is -0.46 or less, the powdery solidified material is added to the soil material, and when the consistency index of the soil material is -0.46 or more, the slurry of [water / solidification material = 1] The method for blending solidified material in improved soil according to claim 1, wherein the solidified material is added to the soil material.   A method for blending a solidifying material and an auxiliary agent in the improved soil, comprising adding an auxiliary agent for improving strength to the improved soil obtained by the method according to claim 1 or 2.

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