JP2018168628A - Manufacturing method of granulated soil and method for granulating swelling portion using the same - Google Patents

Abstract

To make it easy to carry out chipping work and scraping work to cement improved soil even immediately after or even after a lapse of several months after manufacturing the cement improved soil without adding a retardant.SOLUTION: A granulating agent for granulating cement improved soil contains one or both of a water-absorbing polymer and lime. When the granulating agent is the water-absorbing polymer, at least 0.2 kg of the water-absorbing polymer is contained in 1 mof the cement improved soil for carrying out the granulating treatment. Also, when the granulating agent is the lime, at least 20 kg of the lime is contained in 1 mof the cement improved soil for carrying out the granulating treatment. Further, when the granulating agents are the water-absorbing polymer and the lime, at least 0.1 kg of the water-absorbing polymer and at least 10 kg of the lime are respectively contained in 1 mof the cement improved soil for carrying out the granulating treatment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for granulating a cement-improved soil with a granulating agent and producing a granulated soil, and a method for granulating a raised portion using this method.

  Conventionally, in the ground improvement method using cement or a cement-based solidifying material, particularly when a columnar cement improved body is produced, it is necessary to treat the head of the columnar cement improved body. Specifically, when cement slurry or cement powder is poured and mixed with soil, excess cement-improved soil rises above the columnar cement-improved body, so that it exceeds the predetermined height (planned height). The cement-improved soil (raised soil) needs to be removed by mechanical destruction or excavation. For example, it is necessary to lift or scrape it with a heavy machine such as a backhoe while it has low strength on the construction day or the next day.

  However, the depth from the ground surface of the finished surface of the columnar cement improvement body is about 2 m in normal ground improvement, but may be 4 to 5 m or more when a structure such as a basement is made. When the depth of the finished surface of the columnar cement improvement body is 3 m or more, the backhoe cannot reach and the back soil cannot be lifted or scraped off. In such a case, processing will be performed at the root excavation of the next process of ground improvement, but since the raised part has already hardened and becomes high strength, the operator can suspend using an excavator such as a breaker. Do work. This work is a heavy labor, has a problem that takes a lot of time, and uses an excavator such as a breaker, which is accompanied by vibration and noise, and is not preferable from the viewpoint of environmental consideration in the surrounding area.

  In order to eliminate these points, the rotating blade is fixed horizontally to the tip of the rotating shaft, and a plurality of jets are provided in the rotating blade and rotated while injecting the liquid agent to separate the excess ready-mixed concrete from the pile head, A pile head processing apparatus is disclosed in which unnecessary portions are scraped off after curing to facilitate crushing (see, for example, Patent Document 1).

  In the pile head treatment equipment configured in this way, the liquid agent is injected into the unnecessary portion of the ready-mixed concrete from the rotating blades at the tip of the rotating shaft while rotating the rotating shaft, and the cement in the ready-mixed concrete is diluted by stirring and mixing. As a result, the cement and the aggregate are not fixed. As a result, the cement and aggregate separate and precipitate, so that the strength after hardening becomes very weak and it becomes easy to remove unnecessary portions. In this way, with a relatively simple structure and principle, an unnecessary portion of the pile can be easily scraped off in a short time, and the pile head processing can be performed without generating noise or dust.

  Further, a pile head processing device is disclosed that is exchangeable with an excavating and stirring device that rotates in the ground by receiving a driving force from a base machine and forms a columnar ground improvement body made of soil cement in the ground. (For example, refer to Patent Document 2). In this pile head processing apparatus, a shaft that rotates in the ground is mounted on a base machine. Further, the surplus portion formed by raising the head of the ground improvement body from the specified depth is made of uncured soil cement, and a plurality of cutting blades for cutting the surplus portion extend in the radial direction at the bottom of the shaft body. Provided.

  In the pile head processing device configured in this way, the excavation and stirring device is attached to the base machine, the excavation and stirring device is rotated in the ground, the ground is excavated and stirred to a predetermined depth, and the ground improvement made of soil cement reaches the predetermined depth After forming the body, the excavator agitation device is pulled up to the ground, this excavator agitation device is replaced with a pile head treatment device, and the surplus portion made of unhardened soil cement on the head of the ground improvement body is removed from the pile head treatment device. Remove by cutting with multiple cutting edges. As a result, since the scraping work by the backhoe is not required, the work safety is improved, and the head of the ground improvement body can be finished with high quality.

JP-A-06-212626 (Claim 1, paragraphs [0005] and [0008], FIG. 1) JP, 2006-108886, A (claims 1 and 3, paragraph [0014], FIG. 1, FIG. 2 and FIG. 6)

  However, in the above-mentioned conventional pile head processing apparatus disclosed in Patent Document 1, liquid agent is sparsely poured into the ready-mixed concrete and oozes out to the surrounding ground due to the overload pressure (the earth pressure in the vertical direction). There was a possibility that (stake head) would be hardened again. Moreover, in the pile head processing apparatus shown by the said conventional patent document 2, the pile head after excavation agitation by the excavation agitation apparatus is re-stirred by the excavation agitation apparatus, the top pressure (the earth pressure in the vertical direction), and the surrounding ground. There was a risk of re-curing under the influence of water supply. Hereinafter, the “pile head” is referred to as a “swelled portion” in this specification. Furthermore, immediately after the ground is improved, the raised portion (excess cement improved soil) is still relatively soft, so this raised portion can be easily removed from the columnar cement improved body. It may not be possible to process the climax part for a month. If the raised part is left as it is for several months, there is a problem that the raised part is solidified. As described above, when the raised portion is re-cured or solidified, the raised portion that has been re-cured or solidified has a problem that it takes a very long time to hang or scrape. Although there is a method of delaying solidification by adding and mixing a chemical solution such as a retarder to the swelled part, if the above agent is mixed into the planned columnar cement improvement body, the columnar cement improvement body becomes insufficient in strength. There was a problem.

  The first object of the present invention is to suspend the cement-improved soil immediately after producing the cement-improved soil without adding any agent such as a retarder or after several months. An object of the present invention is to provide a method for producing granulated soil, which can easily perform a scraping operation. The second object of the present invention is to granulate the swelled portion on the columnar cement improvement body, so that this swelled portion even immediately after the ground improvement or after several months have elapsed since the ground improvement. It is an object of the present invention to provide a method for granulating the swelled portion, which can be easily removed.

  In the columnar cement improvement body produced by the ground improvement method using cement or a cement-based solidifying material, the present inventors are able to absorb water when removing a bulging portion that exceeds a specified height (planned height). It is found that a swelled portion (excess cement-improved soil) can be easily removed by adding and mixing either one or both of a polymer substance and quicklime to produce a granulated treated soil. It came.

A first aspect of the present invention is a method for producing a granulated soil obtained by granulating cement-modified soil with a granulating agent, wherein the granulating agent is either a water-absorbing polymer substance or quicklime. Or both, and when the granulating agent is a water-absorbing polymer material, the water-absorbing polymer material is granulated by containing at least 0.2 kg of 1 m ^{3 of} cement-improved soil. When it is quicklime, quicklime is granulated by containing at least 20 kg of 1 m ^{3 of} cement-improved soil, and when the granulating agent is a water-absorbing polymer substance and quicklime, the water-absorbing polymer substance and quicklime are cement. It is characterized in that it is granulated by containing at least 0.1 kg and 10 kg respectively for 1 m ^{3 of the} improved soil.

  The 2nd viewpoint of this invention is the method of granulating a swelling part by the method as described in a 1st viewpoint, after forming a columnar cement improvement body in the ground.

According to a third aspect of the present invention, a columnar cement improvement body that increases in strength with the passage of time is formed in the ground, and the Procter needle penetration resistance value of the cement improvement body is 3.0 N / mm ² or less. In this method, the swelled portion is granulated by the method described in the first aspect.

  In the method for producing granulated soil according to the first aspect of the present invention, since the granulating agent contains either or both of a predetermined amount of the water-absorbing polymer material and quicklime, the cement-improved soil is treated with the granulated material. When granulated with granulating agent to produce granulated soil, the cement modified soil can be easily lifted and scraped even after the cement modified soil has been prepared or after several months have passed. Can be removed. This is because when the water-absorbing polymer substance is uniformly dispersed in the cement-improved soil, the water-absorbing polymer substance absorbs free water in the cement-improved soil, thereby expressing the strength of the cement-improved soil. This is probably because water necessary for hydration of the cement and solidified body is taken away, and a granulated treated soil that does not develop strength even after several months is obtained. Even when water such as rainwater or groundwater is supplied, the water-absorbing polymer does not chemically bond with the cement component, so it remains in a granulated state without re-hardening, forming a weakened portion. To do.

  In the method of granulating the swelled portion according to the second aspect of the present invention, when the swelled portion on the columnar cement improvement body is granulated by the method described in the first aspect, this swelled portion has passed several months. Even if it is just after the ground improvement or after a few months have passed since the ground improvement, it is easy to lift and scrape the raised part because it is formed with granulated treated soil that does not show strength even Can be removed.

In the method for granulating the swelled portion according to the third aspect of the present invention, while the Procter needle penetration resistance value of the cement-improved body is 3.0 N / mm ² or less, it is granulated by the method according to the first aspect. Since the resistance value of the cement-improved soil in the portion forming the bulging portion is small when the pulverizing treatment is performed, the granulating agent can be agitated and mixed with relatively small energy. As a result, the water-absorbing polymer material and the like are uniformly dispersed in the cement-improved soil of the portion that forms the raised portion, and the raised portion is formed by the granulated treated soil that does not exhibit strength even after several months. This raised portion can be easily removed by lifting or scraping.

It is a cross-sectional block diagram which shows the column-shaped cement improvement body in the ground, and its surrounding state. It is a section lineblock diagram showing the procedure which produces a columnar cement improvement object in the ground.

Next, an embodiment for carrying out the present invention will be described with reference to the drawings. The granulated soil is produced by granulating a cement-improved soil improved by cement or a cement-based solidifying material with a granulating agent. The cement-based solidifying material preferably contains cement or cement as one of its components, and further contains at least one substance selected from blast furnace slag, slaked lime or gypsum. Examples of the cement include Portland cement, C ₂ S special cement [2CaO · SiO ₂ (belite) cement clinker mineral name], super-hard cement, calcium sulfoaluminate special cement, and the like.

  The granulating agent contains one or both of a water-absorbing polymer substance and quicklime. As the water-absorbing polymer substance, at least one selected from natural polymers, synthetic polymers, or a mixture thereof is used. Examples of natural polymers include starch polymer materials, cellulose polymer materials, polyvinyl alcohol compounds, acrylic polymer materials, and condensation polymers. Specific examples of the starch-based polymer substance include starch-acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer, starch-acrylamide graft polymer, and the like. Specific examples of the cellulose-based polymer substance include And cellulose-acrylonitrile graft polymers, and specific examples of polyvinyl alcohol compounds include polyvinyl alcohol crosslinked polymers. Specific examples of the acrylic polymer material include sodium polyacrylate crosslinked product, saponified polyacrylonitrile polymer, hydroxyethyl methacrylate polymer and the like, and specific examples of the condensation polymer include maleic anhydride Polymers, polyether-based, ester-based polymers, etc. On the other hand, examples of the synthetic polymers include vinylon polymer materials and polyester polymer materials.

When the granulating agent is a water-absorbing polymer material, the water-absorbing polymer material is granulated by containing at least 0.2 kg, preferably 0.2 to 55 kg, of 1 m ^{3 of} cement-improved soil. When the granulating agent is quick lime, the quick lime is granulated by containing at least 20 kg, preferably 20 to 300 kg, with respect to 1 m ^{3 of} cement-improved soil. Further, when the particulate treatment agent is a water-absorbing polymeric substances and quicklime, at least 0.1kg and 10kg water-absorbing polymeric substances and quicklime on cement improved soil 1 m ^3, preferably 0.1~50kg and 10 ˜150 kg each is contained and granulated. Here, the content ratio of the water-absorbing polymer substance and quicklime to the 1 m ³ cement-improved soil is limited to the above range. If the content is less than the above range, the water-absorbing polymer substance does not reach the cement-improved soil and a few months have passed. This is because the strength of the cement-improved soil appears. The content ratio of the water-absorbing polymer substance and quicklime is a range obtained by setting the wet density of the cement-improved soil to 1.1 to 2.2 g / cm ³ and the moisture content of the cement-modified soil to 10 to 200%. .

  In the method for producing granulated soil thus configured, the granulating agent contains a predetermined amount of either one or both of the water-absorbing polymer material and quicklime. When uniformly dispersed in the improved soil, the water-absorbing polymer substance absorbs free water in the cement-modified soil, and is necessary for hydration of the cement and solidified body in order to develop the strength of the cement-modified soil. After the water is taken away, a granulated soil that does not develop strength even after several months is obtained. As a result, even immediately after the cement-improved soil is produced or after several months have passed, the cement-improved soil can be easily removed by a hanging operation or a scraping operation.

A method for forming the raised portion with the granulated soil will be described with reference to FIGS. Here, the raised portion refers to the head of the columnar cement improvement body, that is, the excess cement improvement soil above the planned height H ₁ of the columnar cement improvement body. As shown in FIG. 1, when a columnar cement improvement body 11 is produced in the ground, an excessive cement-treated soil called a raised portion 14 is generated at the head of the columnar cement improvement body 11. It is necessary to remove the cement-treated soil. First, a columnar cement improvement body is formed in the ground. Specifically, first, as shown in FIG. 2 (a), after aligning the tip of the rod 13a of the mechanical stirring device 13 with the center of the columnar cement improvement body 11 to be constructed, the rod 13a is rotated, As shown in FIG.2 (b), it excavates to the predetermined | prescribed air digging depth as needed. Next, a slurry-like filler made of cement or a cement-based solidifying material is injected from the tip of the rod 13a, and the blade 13b, 13d is rotated while rotating. This stirs and mixes the filler and excavated soil. Furthermore, as shown in FIGS. 1 and 2 (c), to stop the infusion was reached a predetermined depth (the lower end of an H ₁ in FIG. 1), by reversing the rod 13a, and the filler and the excavated soil The rod 13a is pulled up while stirring. Then, when the tip of the rod 13a is pulled to plan the upper end of the height H ₁ (FIG. 1), to start the injection of particulate treatment agent, the blade 13b, while rotating the 13d, pulling the rod 13a. Here, reference numeral 13c in FIG. 2 is a co-rotation preventing wing for preventing the co-rotation phenomenon of soil.

The columnar cement improvement body formed in the ground becomes stronger with time. For this reason, the granulating agent has a planned height H of the cement improvement body while the Procter needle penetration resistance value of the cement improvement body is 3.0 N / mm ² or less, preferably 2.0 N / mm ² or less. It is poured into surplus cement improvement soil above the top of ₁ . Thus raised portion consisting of granulated treated soil above the planned upper end of the height H ₁ of the cement improved is formed. Here, the Proctor needle penetration of the resistance value is limited to 3.0 N / mm ² or less, the strength of the cement improved soil exceeds 3.0 N / mm ² cement improved body when injecting particulate treatment agent This is because it becomes too high and a large amount of energy is required to stir and mix the cement-improved soil when the granulating agent is injected, which is not economical and the cement-improved soil may not be sufficiently granulated. The Proctor needle penetration resistance value is the penetration resistance value of the granulated soil measured by the same method as the concrete setting test method (JIS A 1147).

In this embodiment, the solidifying material injection and the granulating process are performed in one step, but the solidifying material injection and the granulating process may be performed in two steps. Specifically, in this embodiment, the solidification material was injected when the rod was drilled and the granulation process was performed when the rod was pulled up, but after the solidification material was injected when the rod was drilled, the granulation process was not performed. The rod may be pulled up and granulated in another step. Further, in this embodiment, as a device for producing granulated soil, a mechanical stirring device for producing a columnar cement improvement body is used, and instead of injecting cement slurry or cement powder, granulation treatment is performed. Although the granulated treated soil was produced above the upper end of the planned height H ₁ by adding the agent and stirring, a dedicated device for producing the granulated treated soil with a portable type was produced. the granulation process soil above the planned upper end of the height H ₁ using may be produced. In this case, it is possible to produce granulated soil with a normal hand mixer. For example, by adjusting the length of the rod of the hand mixer, it is possible to produce the granulated soil even if the planned height of the cement improvement body is deep, for example, about 5 m from the ground surface.

Protuberances thus formed, i.e. above the excess cement improved soil from the upper end of the planned height H ₁ of the columnar cement improved body is formed by granulation process soil strength even after a few months does not express Therefore, even immediately after the ground improvement or after several months have passed since the ground improvement, the raised portion can be easily removed by the lifting work or the shaving work. In addition, while the improved procter needle penetration resistance value of the cement improved body is 3.0 N / mm ² or less, the raised portion is formed by the granulated treated soil prepared by the above method, so the cement of the portion forming the raised portion Since the resistance value of the improved soil is small, the granulating agent can be stirred and mixed with relatively small energy. As a result, the water-absorbing polymer material and the like are uniformly dispersed in the cement-improved soil of the portion that forms the raised portion, and the raised portion is formed by the granulated treated soil that does not exhibit strength even after several months. This raised portion can be easily removed by lifting or scraping.

  Next, examples of the present invention will be described in detail together with comparative examples.

<Example 1>
In the indoor formulations tested, as the target soil, cohesive soil (collected at Saitama Niiza, wet density 1.65 g / cm ^3, water content ratio 67.5%) using a cement-based solidifying material Yusutabira 50 (manufactured by Ube-Mitsubishi Cement Corp. , Symbol: US50), the cement-improved soil with W / C = 100% was prepared at 300 kg / m ³ . Here, W / C = 100% means that the mass ratio of water (W) to cement (C) is 1: 1. Then, 1 kg of the above cement-improved soil was added with ³ kg of soil hard (Mitsubishi Chemical Co., Ltd., symbol: SH, water-absorbing polymer substance) as a granulating agent after 1 hour had elapsed since the cement-improved soil was produced. Added. This granulated soil was designated as Example 1.

<Examples 2 to 4 and Comparative Example 1>
The time from the preparation of the cement-improved soil to the addition of the granulating agent (Soil Hard (Mitsubishi Chemical Co., Ltd., symbol: SH, water-absorbing polymer)) and the amount of granulating agent added to the cement-improving soil The granulated soil was produced in the same manner as in Example 1 except that the changes were made as shown in Table 1. These granulated soils were designated as Examples 2 to 4 and Comparative Example 1.

<Comparative test 1 and evaluation>
For the granulated treated soils of Examples 1 to 4 and Comparative Example 1, the granulation determination was performed visually and the Proctor needle penetration resistance value was measured. The results are shown in Table 1. In addition, in the granulation determination in Table 1, “excellent” means that the entire granulated soil has been granulated, “good” means that a portion of the granulated soil has been granulated, “impossible” "Means a state in which the granulated soil is not granulated. Further, the Proctor needle penetration resistance values in Table 1 are penetration resistance values of the granulated soil measured by the same method as the concrete setting test method (JIS A 1147).

As is clear from Table 1, in Comparative Example 1 in which the time from the preparation of cement-treated soil to the addition of the granulating agent was as long as 24 hours, the Proctor needle penetration resistance value was increased to 5.5 N / mm ² , Judgment determination was impossible because it was not granulated. On the other hand, in Examples 1 to 4 in which the time from the preparation of the cement-treated soil to the addition of the granulating agent is 1 to 8 hours, the Proctor needle penetration resistance value is 0.4 to 2.8 N / Mm ² , and the granulation determination was excellent in a state where the whole was granulated and partly granulated.

<Example 5>
In the indoor blending test, Kanto Loam (collected in Kawasaki City, Kanagawa Prefecture, wet density 1.31 g / cm ³ , moisture content 131.7%) was used as the target soil, and cement-based solidified material youth tabiler 50 (manufactured by Ube Mitsubishi Cement Co. , Symbol: US50) was added to 350 kg / m ^3, and cement improved soil with W / C = 60% was prepared. Here, W / C = 100% means that the mass ratio of water (W) to cement (C) is 1: 1. Then, 0.2 kg of soil hard (manufactured by Mitsubishi Chemical Corporation, symbol: SH, water-absorbing polymer substance) was added as a granulating agent to 1 m ³ of the cement-improved soil. This granulated soil was designated as Example 5.

<Examples 6-15 and Comparative Examples 2-6>
Granulation treatment in the same manner as in Example 5 except that the type and amount of granulation treatment agent and the time from preparation of cement-improved soil to addition of granulation treatment agent were changed as shown in Table 2. Each soil was made. These granulated soils were designated as Examples 6 to 15 and Comparative Examples 2 to 6.

<Comparative test 2 and evaluation>
For the granulated treated soils of Examples 5 to 15 and Comparative Examples 2 to 6, in the same manner as in Comparative Test 1, the granulation determination was performed visually and the Proctor needle penetration resistance value was measured. The results are shown in Table 2. In the granulation determination in Table 2, “excellent” means that the entire granulated soil has been granulated, “good” means that a portion of the granulated soil has been granulated, "" Means that the granulated treated soil is granulated, but it is sticky or cramped and difficult to handle as treated soil. "No" means that the granulated treated soil is not granulated. Further, the Proctor needle penetration resistance values in Table 1 are penetration resistance values of the granulated soil measured by the same method as the concrete setting test method (JIS A 1147).

As is apparent from Table 2, in Comparative Example 2 where no granulating agent was added, the Proctor needle penetration resistance value was as small as 0.3 N / mm ² , but the granulation determination was not possible because it was not granulated. Met. In Comparative Example 3 in which soil hard (Mitsubishi Chemical Co., Ltd., symbol: SH, water-absorbing polymer substance) as a granulating agent was added as little as 0.1 kg to 1 m ³ of cement-improved soil, Proctor needle penetration resistance was Although it was as small as 0.3 N / mm ² , the granulation determination was impossible because it was not granulated. In contrast to these examples, soil hard (Mitsubishi Chemical Co., Ltd., symbol: SH, water-absorbing polymer substance) as a granulating agent was added in an appropriate amount of 0.2 to 55 kg to 1 m ³ of cement-improved soil. in 5-8, Proctor needle penetration resistance value is as small as 0.3 N / mm ^2, yet do granulation judgment is good in a state of partially granulated, in a state in which the whole was granulated Yu Or it was difficult to handle as treated soil, but it was possible to be in a granular state.

Further, in Comparative Example 3 in which quick lime (manufactured by Ryoko Lime Industry Co., Ltd., symbol: CaO) as a granulating agent was added as little as 0.1 kg with respect to 1 m ³ of cement-improved soil, the Proctor needle penetration resistance value was 0.3 N. Although it was as small as / mm ² , the granulation determination was impossible because it was not granulated. In contrast, in Examples 9 to 11 in which quick lime (manufactured by Ryoko Lime Industry Co., Ltd., symbol: CaO) as a granulating agent was added in an appropriate amount of 20 to 310 kg to 1 m ³ of cement-improved soil, a proctor needle The penetration resistance value is as small as 0.3 N / mm ² , and the granulation judgment is good in a partly granulated state, the whole part is granulated, or is excellent, or treated soil As it was difficult to handle, it was possible to be in a granular state.

Also, quick lime (made by Ryoko Lime Industry Co., Ltd., symbol: CaO) as a granulating agent was added in an appropriate amount of 50 kg to 1 m ³ of cement-improved soil. In Comparative Example 5 where the time until the addition was as long as 7 hours, the Procter needle penetration resistance value was as large as 3.1 N / mm ² , and the granulation determination was not possible due to the non-granulated state. On the other hand, quick lime (manufactured by Ryoko Lime Industry Co., Ltd., symbol: CaO) as a granulating agent is added in an appropriate amount of 50 kg to 1 m ³ of cement-improved soil. In Example 12, in which the time until the addition of 6 is appropriate, the Proctor needle penetration resistance value was as small as 3.1 N / mm ² , and the granulation judgment was good with a partly granulated state. It was.

Furthermore, as a granulating agent, soil hard (Mitsubishi Chemical Co., Ltd., symbol: SH, water-absorbing polymer substance) is added as small as 0.05 kg to 1 m ³ of cement-improved soil, and quicklime (Ryokko Lime Industry Co., Ltd.) is added. In Comparative Example 6 in which a small amount of 45 kg was added to 1 m ³ of cement-improved soil, the Proctor needle penetration resistance value was 0 N / mm ² and there was no resistance. It was impossible. On the other hand, soil hard (Mitsubishi Chemical Co., Ltd., symbol: SH, water-absorbing polymer substance) as a granulating agent was added in an appropriate amount of 0.1-50 kg to 1 m ³ of cement-improved soil, and quicklime was added. In Examples 13 to 15 in which an appropriate amount of 10 to 300 kg was added to 1 m ³ of cement-improved soil (manufactured by Ryoko Lime Industry Co., Ltd., symbol: CaO), the proctor needle penetration resistance value was 0.3 to 0.00. 5N / mm ² , and the granulation determination was good in a partly granulated state, or in a state of being difficult to handle as treated soil but in a granulated state.

  The method for producing a granulated treated soil of the present invention can be suitably used, for example, in the field of ground improvement.

11 Cement improvement body 14 Swelling part

Claims (3)

A method for producing a granulated soil obtained by granulating cement improved soil with a granulating agent,
The granulating agent contains one or both of a water-absorbing polymer substance and quicklime,
When the granulating agent is the water-absorbing polymer material, the water-absorbing polymer material is granulated by containing at least 0.2 kg of 1 m ^{3 of the} cement-improved soil,
When the granulating agent is the quicklime, the quicklime is granulated by containing at least 20 kg with respect to 1 m ^{3 of the} cement-improved soil,
When the granulating agent is the water-absorbing polymer substance and the quicklime, the water-absorbing polymer substance and the quicklime are granulated by containing at least 0.1 kg and 10 kg, respectively, with respect to 1 m ^{3 of the} cement-improved soil. A method for producing granulated soil characterized by being treated.   A method for granulating a raised portion by the method according to claim 1, after forming a columnar cement improvement body in the ground. The columnar cement improvement body which becomes high in strength with the passage of time is formed in the ground, and the Procter needle penetration resistance value of the cement improvement body is 3.0 N / mm ² or less. A method of granulating the raised part.

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