JP2018021303A - Manufacturing method of fluidized soil cement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of fluidized soil cement that suppresses generation of excess water to an extent possible, while securing fluidity by a simple method.SOLUTION: A manufacturing method of fluidized soil cement includes: a first step in which water is added gradually while agitating local sediment placed in a container, to shift to turbid water from a paste-like state, and water is added further until a material separation state is reached that keeps the materials separated when agitation has stopped, and an added water amount for reaching the material separation state is confirmed immediately thereafter; and a second step in which cement is gradually added while agitating the mixture in the container that has reached the material separation state, until the mixture in the container resumes to the paste-like state that does not let a soil particle and water separate even after agitation has stopped, and confirming an added cement amount immediately after reaching the paste-like state. Cement milk is blended based on the added water amount for reaching the material separation state and the added cement amount, and the blended cement milk is mixed with the local sediment to manufacture the fluidized soil cement.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for producing fluidized soil cement for ground improvement or construction of civil engineering structures.

  Conventionally, in civil engineering and sabo work, the INSEM method has been used to agitate the locally generated earth and sand with a backhoe (power excavator) bucket and compact it with a rolling roller to construct a civil engineering structure for forestry and sabo. In addition, the ISM method is used to improve the ground by constructing civil engineering structures for forestry and erosion control by mixing and mixing locally generated soil and cement milk, etc., with heavy equipment equipped with a backhoe or twin head stirring device. Are known.

  Among them, in the ISM method, the soil of the foundation ground is rocked and mixed with cement milk to solidify it as soil cement to improve the ground, or the local soil and cement milk are mixed and poured into the formwork. Construction is being done by constructing structures for sabo.

  Soil cement for ground improvement or construction of civil engineering structures used for such ISM construction is required to have high fluidity from the viewpoint of workability due to the particle size and moisture content of the local earth and sand, and has a high water cement ratio. Currently, fluidized soil cement having a slump value of about 20 cm or more by mixing local soil with cement milk is used.

  However, if the slump value is high, there is a problem that in the severe winter season, surplus water freezes and expands and cracks occur in the structure made of soil cement. In addition, when the slump value is high, the soil cement causes drying shrinkage even in summer, and there is a problem that the structure is cracked.

  Thus, when there is much excess water in soil cement, there exists a possibility that a problem may arise in quality, and it has been a subject to reduce excess water from soil cement as much as possible, ensuring workability. However, in the construction sites of Sanjiyama and erosion control, priority is given to ensuring the workability, that is, the fluidity of the soil cement, and even the amount of surplus water is not known at present. is there.

  As a method for producing soil cement in consideration of the moisture content of the local soil, for example, in Patent Document 1, using a standard composition table in which the composition of cement milk is determined according to each soil quality, Obtain the basic composition for the average ground by weighted average of the layers, and distribute the total amount of cement milk obtained by this basic composition to each layer of the target ground using the cement milk injection rate of each soil in the standard composition table In addition, a soil cement body construction method is disclosed in which an optimum amount of cement milk is injected into each layer of the target ground obtained by distribution to construct a soil cement body of uniform quality in the depth direction (patent document) 1 paragraphs [0020] to [0028], FIG. 1 of the drawings, etc.).

  However, the soil cement body construction method described in Patent Document 1 is used as a soil cement wall used for a mountain retaining, etc., even if the same soil cement is used, unlike the fluidized soil cement used for mountain conservation and sabo work. The soil cement body to be produced is developed, and the development of desired strength is required as an absolute condition. For this reason, as described above, it is necessary to obtain an optimum amount of cement for each layer of the target ground, and there is a problem that it takes time and effort to determine the composition. In particular, the soil cement body construction method described in Patent Document 1 creates a standard composition table for each soil quality, but the soil cement used for a sabo dam or the like uses soil and sand close to the surface layer, and thus variation increases. Actually, the actual composition of the local soil is determined for each site, and there is a problem that it is not possible to create a standard composition for each soil type.

  Further, in Patent Document 2, high fluidized mortar having a water-cement ratio of 65 to 80% can be pumped into a cloth formwork, and the amount of cement used and material separation can be reduced while ensuring fluidity. A method for forming a highly fluidized mortar using a cloth formwork is disclosed.

  However, the molding method of the highly fluidized mortar described in Patent Document 2 can maintain the fluidity of the conventional mortar by suppressing material separation and breathing, but it uses fine aggregate whose grain size is adjusted such as crushed stone and sand. The fluidized soil cement used for forestry and sabo work is not applicable because it is used for aggregates that do not have a limited particle size distribution, such as local sediment. In addition, it is also known that when mortar is placed on a cloth form, surplus water not related to the hydration reaction oozes out of the cloth, resulting in an improved water-cement ratio and increased expression strength. However, since the gravity of the mortar that has not yet hardened acts on the cloth formwork as pressure, the cloth formwork cannot have a large cross section, and the thickness is limited to about 30 cm, making it a tall structure. Has a problem that it cannot be used as it is. In particular, the molding method of the high fluidized mortar described in Patent Document 2 is intended for aggregates whose particle size is strictly adjusted, and in soil cement using locally generated soil, the mixture of fine-grained soil is natural and strict. There was a problem that the particle size could not be adjusted.

JP 2010-0777748 A JP-A 63-64950

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is a fluidized soil that can suppress the generation of excess water as much as possible while ensuring fluidity by a simple method. The object is to provide a method for producing cement.

  A method for producing a fluidized soil cement according to the first invention is a method for producing a fluidized soil cement for ground improvement or construction of a civil engineering structure, wherein a predetermined amount of local earth and sand at a construction site is placed in a container and stirred. Gradually add water and remove from the paste form to make suspended water in which the soil particles float in the water. Then, when the stirring is stopped, water is added until the soil particles are in a state of material separation that sinks into the water, followed by separation. A step of confirming the amount of water to be added and a step of confirming the amount of water to be added, and gradually adding cement to the mixture in the container in the material separation state in the step of confirming the amount of water to be separated while stirring. A cement addition amount confirmation step of adding cement until the soil particles and water return to a paste form that does not separate even when stopped, and confirming the cement addition amount immediately after the paste is formed. When, with the cement amount, to prepare a cement milk based on, characterized in that to produce a fluidized soil cement by mixing a local sediment in blended cement milk.

  The fluidized soil cement manufacturing method according to the second invention is a fluidized soil cement manufacturing method for ground improvement or construction of civil engineering structures, wherein a slump test of a mixture of local soil and water at a construction site is performed. And when the slump cone is lifted, the mixture separated and demolded collapses, and the decay water amount confirmation step for confirming the decay water amount, which is the minimum amount of water that makes slump measurement impossible, A slump test of the mixture of the above-mentioned decayed water and cement added to the local earth and sand, when the slump cone is lifted, the material does not separate and becomes a paste, and the minimum amount of cement that can be measured for slump. A slump formation cement addition amount confirmation step for confirming a slump formation cement addition amount, based on the decay water addition and the slump formation cement addition amount. There were blended cement milk, a mixture of local sediment in blended cement milk, characterized in that to produce a fluidized soil cement.

  A method for producing a fluidized soil cement according to the third invention is a method for producing a fluidized soil cement for ground improvement or construction of a civil engineering structure, wherein a target slump value is determined in a slump test, and a plurality of samples corresponding thereto are determined. And a step of determining a water cement ratio and a minimum cement amount from a plurality of samples to be created, and each water cement ratio and a minimum cement amount are obtained while gradually increasing a target slump value. The fluidized soil cement is manufactured based on the water cement ratio and the minimum cement amount at the minimum slump value in which fluidity was confirmed by tapping.

  A fluidized soil cement manufacturing method according to a fourth aspect of the present invention is the fluidized soil cement according to any one of the first to third aspects of the invention, wherein the fluidized soil cement is packed in a cloth mold, and excess water is discharged from the gap of the cloth mold. It is characterized by exuding excess water.

  According to 1st invention-4th invention, even if the particle size, moisture content, etc. of local earth and sand are unknown, the flow required for fluidized soil cement for ground improvement or civil engineering structure construction by a simple method It is possible to produce a fluidized soil cement that secures the properties and suppresses the generation of excess water as much as possible.

  In particular, according to the fourth aspect of the present invention, excess water is oozed out from the gaps in the cloth formwork to eliminate the excess water, so that the excess water is further excluded from the soil cement when cured, and the water cement ratio is reduced. This improves the strength when the soil cement is cured.

It is explanatory drawing explaining the concept of the water required for soil cement. It is a flowchart which shows each process of the manufacturing method of the fluidized soil cement which concerns on 1st Embodiment of this invention. It is a flowchart which shows each process of the manufacturing method of the fluidized soil cement which concerns on 2nd Embodiment of this invention. It is a vertical sectional view which shows the state which cut | disconnected the slump cone which performs a slump test by the central axis. It is process explanatory drawing which shows the procedure of a slump test. It is a flowchart which shows each process of the manufacturing method of the fluidized soil cement which concerns on 3rd Embodiment of this invention. It is explanatory drawing which shows the outline of the manufacturing method of the fluidized soil cement which concerns on 3rd Embodiment of this invention.

  Hereinafter, the manufacturing method of the fluidized soil cement which concerns on embodiment of this invention is demonstrated in detail, referring drawings.

  First, the concept of excess water and water necessary for soil cement will be described in detail with reference to FIG. Drawing 1 is an explanatory view explaining the concept of water required for soil cement. As shown in FIG. 1, the water related to the soil cement includes the following plural types of water.

(Water used for hydration reaction)
The minimum required water is water used for cement hydration. From the experimental results, in the case of fluidized soil cement, it has been found that the water used for the hydration reaction of the cement is about 25% by weight with respect to the cement.

(Water absorbed by earth and sand)
In addition to water used for cement hydration, there is water that is absorbed by the earth and sand. The water absorbed by the earth and sand is water that is irrelevant to the hydration reaction, is water that is combined with the earth particles of the earth and sand and is taken into the earth and sand. When water is added beyond the water absorbed by the earth and sand, it becomes free water.

(Water required for compaction)
Water that affects the workability of soil cement is necessary for compaction. The water necessary for this compaction is water that is not related to the hydration reaction, and is not absorbed by the soil particles of the earth and sand, but is present in the soil particle gap to improve the compaction effect of the soil cement. It refers to the water required.

(Water required for fluidization)
In addition to the water required for compaction, water that affects the workability of soil cement includes water required for fluidization of sediment. The water required for fluidization of the earth and sand is water that is not related to the hydration reaction, and is necessary for fluidizing the soil cement that is present in the interstices of the soil particles and is not yet solidified by dispersing the soil particles. pointing.

  As shown in Fig. 1, in the case of a rolling compaction type soil cement that is rolled by heavy machinery or rammer during ground improvement, the required water is the water used for the hydration reaction + the water absorbed by the soil + This water is necessary for compaction. However, when the amount of fine particles of earth and sand increases, the earth and sand become balls (lumps), making it difficult for cement to reach the entire earth and sand. In other words, in order to further improve the workability of soil cement and make it a fluid-type soil cement that is easy to use for the construction of any civil engineering structure, more water is required than that required for compaction. It becomes. For this reason, water required for fluidization> water required for compaction.

(Surplus water)
There is surplus water as water related to soil cement other than the above. This surplus water is not only irrelevant to the hydration reaction, but also refers to water that does not contribute to improving workability such as compaction and fluidization of earth and sand. The more excess water has an adverse effect on the development of the strength of the soil cement, causing quality deterioration such as drying shrinkage and freezing and thawing.

[First Embodiment]
Next, the fluidized soil cement manufacturing method according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a flowchart showing each step of the fluidized soil cement manufacturing method according to the first embodiment of the present invention. The fluidized soil cement produced by the fluidized soil cement production method according to the first embodiment is water that hardens by a hydration reaction used for ground improvement or construction of civil engineering structures in forestry works or sabo works. Hard material.

(1) Hydrolysis step In the fluidized soil cement manufacturing method according to the first embodiment, first, the local earth and sand at the construction site is placed in a container having a certain volume, such as a steel bucket or a mixer, and a steel mixing rod. Add water gradually while stirring with a mixer.

  In this water addition process, the local earth and sand are kneaded with a mixer or a mixing rod so that they are mixed evenly at the beginning. In addition, the local sediment refers to the locally generated sediment generated by excavation or the like in the local sediment layer in a naturally deposited state, etc. at construction sites such as forestry works and sabo works. By effectively utilizing such local earth and sand for forestry works and sabo work, it is possible to reduce construction costs by reducing aggregate costs and disposal costs of generated earth and sand. This is because the time for carrying out can be reduced and the construction period can be shortened.

  Next, in this hydration process, water is gradually added to the container containing the empty ground soil and sand while stirring with a mixer or a mixing rod. At this time, the mixture of local soil and water in the container differs depending on the soil quality, such as gravel and clay, but the ingredients other than stones such as gravel are initially spread when the water reaches the entire local sediment. It becomes a paste. And after that, when the amount of water increases further, it becomes suspension water in which the soil particles escape from the paste and float in water.

  Here, the determination as to whether or not the mixture in the container has become turbid water, that is, the determination as to whether or not the mixture has become turbid is made as follows. For example, if the local earth and sand is gravel or sandy soil, even if only a small amount of water is added, the soil particles will immediately settle and separate even if stirred. That is, when the stirring is stopped, fine particles such as clay and silt are mixed with water and remain turbid, but coarse particles such as sand and gravel settle immediately.

  For this reason, when the local sediment is gravel or sandy soil, it is necessary to have a state where coarse particles are floating in the turbid water in order to judge that the mixture has become turbid. This is because when there is little water, sandy soil or the like will not become cloudy and sand particles will not float.

  In addition, the judgment of whether or not the local soil has become a turbid state when it is a clay, silt or other viscous soil, the state in which the viscous resistance when stirring is lost, that is, when the mixture stops stirring, the surface Whether or not it is in a liquid state with a viscosity below the level of smoothing immediately. This is because if the amount of water is small, soil particles such as clay and silt do not separate, or even if separated, the viscosity is so strong that if the stirring is stopped, the surface will not be smoothed immediately due to stickiness.

(2) Separation water amount confirmation process In the manufacturing method of the fluidized soil cement according to the first embodiment, water is added while stirring from such a suspended state, and when the stirring is stopped, the soil particles of the mixture in the container The material is separated into water. And the separation water amount confirmation process which confirms and determines the amount of water immediately after becoming the material separation state as a separation water amount is performed.

  Here, the judgment of whether or not the mixture in the container is in a separated state, when the local earth and sand is gravel or sandy soil, when stirring, soil particles once suspended, including coarse particles, Judgment is made based on whether or not the mixture has settled after a lapse of a certain period of time, including fine particles, when stirring is stopped.

  In addition, when the local soil is a viscous soil, the judgment of whether or not the mixture in the container is in a separated state is floating immediately after the mixture is stirred, but after a long time (certain time), soil particles Judgment is made based on whether or not the water has settled.

(3) Cement addition process Next, in the fluidized soil cement manufacturing method according to the first embodiment, a cement addition process is performed in which cement is added to the mixture in a material separation state while stirring. In the cement addition process according to the present embodiment, ordinary Portland cement powder is gradually added as a cement while stirring with a mixer or a mixing rod.

Of course, the cement to be added may be a hardly soluble and highly alkaline powder that elutes calcium hydroxide (Ca (OH) ₂ ) by hydration with water and hardens. For example, as cement, various portland cements such as normal, early strong, moderately hot, super early heat, and low heat, and various mixed cements such as fly ash and blast furnace slag mixed with these portland cements, fine particle cements, etc. are used. It is also possible.

  Further, in the method for producing a fluidized soil cement according to the first embodiment, the amount of cement added is increased, and the mixture is returned to a paste form in which soil particles and water are not separated even when stirring is stopped. A cement addition amount confirmation step is performed by confirming the cement addition amount immediately after becoming.

  Here, the judgment of whether or not the mixture has become a paste is determined by having fluidity and high viscosity in a state where the mixture is uniformly mixed without the soil particles and water separating even when mixing and stirring is stopped. Judgment based on whether or not.

(4) Cement milk blending step Next, in the method for producing a fluidized soil cement according to the first embodiment, the amount of separated water obtained in the previous separated water amount confirmation step and the amount of cement added obtained in the previous cement addition step. A cement cement milk blending process for blending cement milk based on the above is performed. Specifically, in this process, the amount proportional to the volume or weight of the local earth and sand to be mixed is determined by the water-cement ratio determined from the amount of separated water and the amount of cement added obtained in the previous process, and is necessary at the time of construction. Prepare a proper amount of cement milk.

  In addition, the cement milk contains various types of admixtures such as retarders, dispersants, retention agents, fluidizing agents, or water reducing agents, depending on the geology of the local soil and sand, construction work such as mountain conservation works and sabo works, and applications. An agent may be mixed.

(5) Fluidized soil cement manufacturing process Next, in the fluidized soil cement manufacturing method according to the first embodiment, the cement milk prepared in the previous process is mixed with the local earth and sand to manufacture the fluidized soil cement. Conducted chemical cement manufacturing process. Specifically, in this step, after the local earth and sand necessary for construction are stirred and kneaded, the cemented milk prepared in the previous step is gradually added little by little while stirring to produce a fluidized soil cement. This is because a uniform and uniform soil cement can be produced.

(6) Excess water removal step Finally, in the fluidized soil cement manufacturing method according to the first embodiment, the fluidized soil cement manufactured in the previous step is packed in a cloth formwork, and surplus water is discharged from the gap of the cloth formwork. Excess water removal step of exuding excess water is performed.

  Here, the cloth form frame refers to a cloth bag-like or box-like shape formed by weaving or knitting a fiber material, and is a concept including a non-woven fabric.

  By performing this step, surplus water is further excluded from the soil cement during curing, and the strength when the soil cement is cured by reducing the water cement ratio is improved. In addition, at the time of construction, since the soil cement is a fluidized soil cement having a high water cement ratio and high fluidity, the workability is good and the work efficiency is improved. For example, even if there is an inclined surface in the civil structure to be constructed and there are places where filling is difficult at the bottom or the like, it is possible to construct a civil structure without a defective part due to poor filling of the soil cement.

<Operational effect of the fluidized soil cement manufacturing method according to the first embodiment>
According to the method for producing a fluidized soil cement according to the first embodiment described above, an appropriate water cement ratio can be obtained by a simple method even if the particle size or moisture content of the local earth and sand is unknown. . Moreover, according to the manufacturing method of the fluidized soil cement which concerns on 1st Embodiment, since it can be used in a state with high fluidity | liquidity at the time of construction, while workability | operativity is very favorable, at the time of hardening, desired intensity | strength It is possible to manufacture a fluidized soil cement that suppresses the generation of excess water as much as possible while ensuring the above. For this reason, there is little quality deterioration by construction failure etc., and it becomes possible to give an extremely good ground improvement or to construct a civil engineering structure.

[Second Embodiment]
Next, the manufacturing method of the fluidized soil cement which concerns on 2nd Embodiment of this invention is demonstrated using FIGS. FIG. 3 is a flowchart showing each step of the fluidized soil cement manufacturing method according to the second embodiment of the present invention. In addition, the fluidized soil cement manufactured by the method of manufacturing the fluidized soil cement according to the second embodiment is also improved in ground treatment, sabo work, etc. in the same manner as the fluidized soil cement according to the first embodiment described above. Or it is the hydraulic material which hardens | cures by the hydration reaction used for civil engineering structure construction. In addition, the term same as the term used with the manufacturing method of the fluidized soil cement which concerns on the above-mentioned 1st Embodiment, such as local earth and sand and cement, points out the same thing.

(1) Disintegration water amount confirmation process As shown in FIG. 3, in the manufacturing method of the fluidized soil cement which concerns on 2nd Embodiment, first, the slump test of the mixture which mixed the local earth and sand of the construction site was performed. When the slump cone is lifted, the mixture is separated and demolded, and the mixture is disintegrated, and a decay water amount confirmation step is performed to determine and confirm the decay water amount, which is the minimum amount of water that makes slump measurement impossible. .

  The slump test performed in this step is performed according to the slump test of fresh concrete that has not yet hardened, that is, the “JIS A 1101 slump test method of concrete”. FIG. 4 is a vertical sectional view of the central axis showing the slump cone for performing the slump test, and FIG. 5 is a process explanatory view showing the procedure of the slump test.

  The slump cone used in this slump test is the same slump cone as the concrete slump test method. As shown in FIG. 4, the slump cone C1 includes a cone-shaped metal cone body C2 having an upper end inner diameter φ100 mm, a lower end inner diameter φ200 mm, and a height of 300 mm and a thickness of 5 mm or more. The cone body C2 has a presser C3 and a handle C4 at appropriate positions.

  In this process, first, in order to make the local earth and sand uniform, the local earth and sand are put into a steel bucket, a mixer or the like, and the mixture is stirred and air-kneaded. Create a plurality of mixtures with different water-cement ratios near the limit where the soil particles are suspended and the soil particles float in the water.

  Here, the determination of the paste state and the suspended water state is the same as the manufacturing method of the fluidized soil cement according to the first embodiment described above, but the mixture at the time of measuring the slump flow by extracting the slump cone is a puddle-like shape. As a guideline, you can see how it spreads out. That is, when the slump flow is in a state where the soil particles and water are separated, it can be determined that the material is separated, and the slump flow is in a state where the soil particles and water are not separated. If it is, it can be determined as a paste.

  Therefore, in this step, a mixture in a state between the material separation state and the paste state is created visually as described above. Then, as shown in FIG. 5, on the smooth iron plate, the mixture created while pushing the slump cone with a stick is divided into a plurality of times (in the illustrated embodiment, three layers three times) as shown in FIG. Pack to be uniform. Thereafter, the slump cone is slowly pulled out, and the slump flow in which the mixture spreads in a puddle is visually observed.

  Such a slump test is repeated a plurality of times, and the slump flow causes material separation to be in a material separation state, and the decay water amount, which is the minimum water amount for which the slump value cannot be measured, is obtained.

(2) Slump Formation Cement Addition Confirmation Step Next, in the fluidized soil cement manufacturing method according to the second embodiment, as shown in FIG. 3, a slump test of a mixture obtained by adding disintegrated water and cement to the local earth and sand. Confirm the slump formation cement addition amount, which is the minimum cement addition amount that can be measured in the slump when the slump slump cone is lifted up and becomes a paste without material separation Perform the process.

  In this step, first, a mixture composed of local earth and water is prepared with the amount of disintegrated water determined in the previous step, and a certain amount of cement having a different weight is added to form a paste visually. Then, the slump test as described above is repeated a plurality of times on the mixture that is visually pasty to obtain the slump formation cement addition amount that is the minimum cement addition amount that enables slump measurement.

(3) Cement milk blending step Next, in the method for producing a fluidized soil cement according to the second embodiment, the amount of decay water obtained in the previous step of confirming the amount of decay water and the amount of slump-forming cement added in the previous step is confirmed. A cement cement milk blending step of blending cement milk based on the slump formation cement addition amount obtained in the process is performed. Specifically, in this process, the amount proportional to the volume or weight of the local earth and sand to be mixed is determined by the water cement ratio determined from the amount of decay water added and the amount of slump formation cement obtained in the previous process. Sometimes mix the required amount of cement milk.

  Similar to the method for producing fluidized soil cement according to the first embodiment, this cement milk includes a retarder, a dispersant, a geological property of the local earth and sand, a situation of construction work such as mountain conservation work and sabo work, and a use. You may mix various admixtures, such as a retention agent, a fluidizing agent, or a water reducing agent.

(4) Fluidized soil cement manufacturing process Next, in the fluidized soil cement manufacturing method according to the second embodiment, the cement milk prepared in the previous process is mixed with the local earth and sand to manufacture the fluidized soil cement. Conducted chemical cement manufacturing process. Specifically, in this step, after the local earth and sand necessary for construction are stirred and kneaded, the cemented milk prepared in the previous step is gradually added little by little while stirring to produce a fluidized soil cement. This is because a uniform and uniform soil cement can be produced.

(5) Excess water removal step Finally, in the fluidized soil cement manufacturing method according to the second embodiment, the fluidized soil cement manufactured in the previous step is packed in a cloth mold, and surplus water is discharged from the gap of the cloth mold. Excess water removal step of exuding excess water is performed. In addition, the cloth formwork is the same as the manufacturing method of the fluidized soil cement according to the first embodiment described above.

  By performing this step, surplus water is further excluded from the soil cement during curing, and the strength when the soil cement is cured by reducing the water cement ratio is improved. In addition, at the time of construction, since the soil cement is a fluidized soil cement having a high water cement ratio and high fluidity, the workability is good and the work efficiency is improved. For example, even if there is an inclined surface in the civil structure to be constructed and there are places where filling is difficult at the bottom or the like, it is possible to construct a civil structure without a defective part due to poor filling of the soil cement.

<Operational effects of the fluidized soil cement manufacturing method according to the second embodiment>
According to the fluidized soil cement manufacturing method according to the second embodiment described above, an appropriate water cement ratio can be obtained by a simple method even if the particle size or moisture content of the local earth and sand is unknown. . In addition, according to the method for producing a fluidized soil cement according to the second embodiment, since it can be used in a highly fluid state at the time of construction, workability is extremely good, and at the time of curing, a desired strength is obtained. It is possible to manufacture a fluidized soil cement that suppresses the generation of excess water as much as possible while ensuring the above. For this reason, there is little quality deterioration by construction failure etc., and it becomes possible to give an extremely good ground improvement or to construct a civil engineering structure.

[Third Embodiment]
Next, the manufacturing method of the fluidized soil cement which concerns on 3rd Embodiment of this invention is demonstrated using FIG. 6, FIG. FIG. 6 is a flowchart showing the steps of the fluidized soil cement manufacturing method according to the third embodiment of the present invention, and FIG. 7 shows the outline of the fluidized soil cement manufacturing method according to the third embodiment. It is explanatory drawing. In addition, the fluidized soil cement manufactured by the method of manufacturing the fluidized soil cement according to the third embodiment is also improved in ground treatment, sabo work, etc. in the same manner as the fluidized soil cement according to the first embodiment described above. Or it is the hydraulic material which hardens | cures by the hydration reaction used for civil engineering structure construction. In addition, the term same as the term used with the manufacturing method of the fluidized soil cement which concerns on the above-mentioned 1st Embodiment, such as local earth and sand and cement, points out the same thing.

(1) 1st sample preparation process First, in the manufacturing method of the fluidized soil cement which concerns on 3rd Embodiment, the 1st sample preparation process which produces the sample 1 is performed. Specifically, 2 kg of water is added to 5 kg of earth and sand and stirred until the soil particles are separated. Then, cement is put into the liquefied sample 1 with a target of 5 cm slump. The amount of cement (kg) input at this time is defined as “cement amount X1”.

(2) Second Sample Preparation Step Next, in the fluidized soil cement manufacturing method according to the third embodiment, a second sample preparation step for preparing the sample 2 is performed. Specifically, 3 kg of water is added to 5 kg of earth and sand and stirred until the soil particles are separated. Then, cement is poured into the liquefied sample 2 with a target of 5 cm slump. The amount of cement (kg) input at this time is defined as “cement amount X2”.

(3) Water Cement Ratio (W / C) Determination Step Next, in the fluidized soil cement manufacturing method according to the third embodiment, the water cement ratio “W / C 5 cm” of the slump 5 cm is set to “cement amount X1” and “ A water cement ratio (W / C) determination step determined from “cement amount X2” is performed. Specifically, “W / C5 cm” = cement (3 kg−2 kg) / (X2−X3), that is, the amount of cement X1 charged into the sample 1 is multiplied by “W / C5 cm” to obtain “necessary for cement If you subtract from the total amount of water, you will find “water required for sediment” + “water required for fluidization”.

(4) Minimum Cement Amount Determination Step Next, in the fluidized soil cement manufacturing method according to the third embodiment, a minimum cement amount determination step is performed. Specifically, 0.5 kg, 1 kg, 2 kg, and 3 kg of water are added to 5 kg of earth and sand and stirred until the soil particles are separated. Based on the "water required for cement", "water required for earth and sand", "water required for fluidization", and "W / C5cm" obtained in the previous process, the amount of cement corresponding to the amount of water was determined. throw into. Here, “water necessary for cement” = {“water amount” − “water necessary for earth and sand” − “water necessary for fluidization”}, and “cement amount” = “water necessary for cement” / “W / C 5 cm”.

  In addition, a specimen is prepared for each amount of water added and the compressive strength is obtained. The minimum value that shows a proportional relationship between the compressive strength and the cement amount is the minimum value that stably develops strength without material separation, and the cement amount at this time is defined as the minimum cement amount.

(5) Fluidized soil cement minimum cement amount determining step Next, in the fluidized soil cement manufacturing method according to the third embodiment, a fluidized soil cement minimum cement amount determining step is performed. Specifically, if tapping is performed at a slump of 5 cm in the above-described slump test and it does not flow visually, it is determined to be non-flowing, and the amount of water is increased to 10 cm until the fluidity can be confirmed by tapping. Go up 15cm and 20cm. Then, the water cement ratio (W / C) and the minimum cement amount at the minimum slump value of the slump value whose fluidity has been confirmed by the above procedure are obtained, and the fluidized soil cement is manufactured according to these values.

(6) Excess water removal process Finally, in the manufacturing method of the fluidized soil cement according to the third embodiment, the fluidized soil cement manufactured in the previous process is packed in a cloth formwork, and surplus water is discharged from the gap of the cloth formwork. Excess water removal step of exuding excess water is performed. In addition, the cloth formwork is the same as the manufacturing method of the fluidized soil cement according to the first embodiment described above.

<The effect of the manufacturing method of the fluidized soil cement which concerns on 3rd Embodiment>
According to the method for producing a fluidized soil cement according to the third embodiment described above, an appropriate water cement ratio can be obtained by a simple method even if the particle size or moisture content of the local earth and sand is unknown. . In addition, according to the method for producing a fluidized soil cement according to the third embodiment, since it can be used in a highly fluid state at the time of construction, workability is extremely good, and at the time of curing, a desired strength is obtained. It is possible to manufacture a fluidized soil cement that suppresses the generation of excess water as much as possible while ensuring the above. For this reason, there is little quality deterioration by construction failure etc., and it becomes possible to give an extremely good ground improvement or to construct a civil engineering structure.

  As mentioned above, although the manufacturing method of the fluidized soil cement which concerns on 1st-3rd embodiment was demonstrated in detail, all the embodiment mentioned above or illustrated shows one embodiment in implementing this invention. These are merely examples, and the technical scope of the present invention should not be construed in a limited manner.

C1: Slump cone C2: Cone body C3: Presser C4: Handle

Claims (4)

A method for producing a fluidized soil cement for ground improvement or construction of civil engineering structures,
Put a predetermined amount of local soil at the construction site into the container and gradually add water while stirring. Remove from the paste to form suspended water in which the soil particles are suspended in the water. Water separation until the material is in a separated state, and a separation water amount confirmation step for confirming the separation water amount immediately after that,
The paste in which the cement particles are gradually added to the mixture in the container in the material separation state in the separation water amount confirmation step while stirring, and the soil particles and water do not separate even if the mixture in the container stops stirring. A cement addition amount confirmation step for adding cement until it returns to the shape and confirming the cement addition amount immediately after the paste is formed,
Cement milk is prepared based on the amount of separated water added and the amount of cement added, and fluidized soil cement is manufactured by mixing local soil with the prepared cement milk to produce fluidized soil cement. Method. A method for producing a fluidized soil cement for ground improvement or construction of civil engineering structures,
A slump test is performed on the mixture of soil and water at the construction site, and when the slump cone is lifted, the material is separated and the demolded mixture collapses. A decay hydrolysis amount confirmation step for confirming the decay hydrolysis amount which is the amount of water;
A slump test of the mixture of the above-mentioned decayed water and cement added to the local earth and sand, when the slump cone is lifted, the material does not separate and becomes a paste, and the minimum amount of cement that can be measured for slump. A slump formation cement addition amount confirmation step of confirming a certain slump formation cement addition amount,
Cement milk is prepared based on the amount of decay water and the amount of slump formation cement, and fluidized soil cement is produced by mixing local soil with the prepared cement milk. Manufacturing method. A method for producing a fluidized soil cement for ground improvement or construction of civil engineering structures,
Defining a target slump value in the slump test and creating a plurality of samples according to the target slump value;
Determining a water cement ratio and a minimum cement amount from a plurality of samples to be prepared, and
While gradually increasing the target slump value, obtain the water cement ratio and the minimum cement amount for each, and fluidize based on the water cement ratio and the minimum cement amount at the minimum slump value whose fluidity was confirmed by tapping. A method for producing a fluidized soil cement, characterized by producing a soil cement. The fluidized soil according to any one of claims 1 to 3, wherein the fluidized soil cement is packed in a cloth mold and the excess water is oozed out from the gap between the cloth molds to remove the surplus water. Cement manufacturing method.