JP2022120638A - Filler for ground preparation - Google Patents

Abstract

To provide a filler for ground preparation that has sufficient flowability during its pouring with a pressure pump, but does not flow when no pressure is applied; and does not get separated in water and has high stability.SOLUTION: A filler for ground preparation contains at least sand particles, montmorillonite particles, a polymer compound having an anionic functional group in the chain, and water. In a texture test, it shows a deforming level of 0.700 or more and a damping level of 0.700 or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a filling material for cavities existing in the ground, between the ground and a structure, or between the ground in water or between the ground and a structure.

Filling materials used to fill cavities generated between existing structures and the ground that has subsided, cavities generated behind abutments and revetments, and cavities generated around sluice gates and sluice pipe structures are affected by injection pressure. It deforms and flows easily when shear force is applied by the action of , but it is necessary to have high workability and filling property due to the ability to retain its shape when there is no pressure action. Furthermore, it is also necessary that there is no run-down or dilution after filling, even in filling at the water's edge due to non-dilution performance.

As such a filling material, for example, in Patent Document 1, a flow cone is placed on a horizontally placed glass plate, and a grout material obtained by adding additives to the main raw materials of water and cement is added to the flow cone. The flow value, which is the average value of the maximum width of the grout material spread on the glass plate and its vertical width, is 100 to 200 mm, and is stored in a closed container. , The funnel with the outflow port at the tip exposed from the closed container is filled with the grout material, compressed air is sent into the closed container, and the grout in the funnel when a pressure of 0.1 MPa is applied from the atmospheric pressure state. A grouting material having thixotropic properties is disclosed, in which the time it takes for the material to completely flow down from the outlet of the funnel is 0.5 to 3.0 seconds.

JP 2004-284930 A

However, filling materials for ground preparation that fill cavities generated between existing structures and the ground that has subsided, cavities generated behind abutments and revetments, and cavities generated around sluice gates and sluice pipe structures It is necessary to have sufficient fluidity during casting, and to remain in place when pressure is not applied. In addition, it is necessary to be difficult to separate in water even if it is cast in water, and to have high stability in water.

However, most of the filling materials used in Patent Document 1 are grout materials in which cement and water are mixed, and there is a problem of high strength after filling. If the filling area has high strength, it may interfere with the post-construction process. A high-strength filled area may create a boundary with the original ground, form a new water path, and become a weak point. Additionally, the strength of these fill zones is difficult to control and difficult to consider as a structure.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a filling material for filling various cavities, which has sufficient fluidity when driving a pressure pump and does not flow when pressure is not applied. and does not separate in water and has high stability.

The above problems of the present invention are solved by the following present invention.
That is, the present invention (1) contains at least sand particles, montmorillonite particles, a polymer compound having an anionic functional group in its molecular chain, and water,
The deformability in the texture test is 0.700 or more,
The attenuation property in the texture test is 0.700 or more,
To provide a filling material for ground preparation characterized by

Further, the present invention (2) contains at least sand particles, montmorillonite particles, a polymer compound having an anionic functional group in its molecular chain, and water, and has a series elastic modulus E1 of 900 Pa or more. , the parallel modulus E2 is 1,000 Pa or more, the parallel portion viscosity η1 is 10,000 Pa s or more, and the serial portion viscosity η2 is 200,000 Pa s or more. Filling material for ground preparation of (1).

In addition, the present invention (3) contains at least sand particles, montmorillonite particles, a polymer compound having an anionic functional group in the molecular chain, and water, and the supernatant turbidity in a water drop test is The filling material for ground preparation according to (1) or (2), which is 50 or less.

Further, the present invention (4) is characterized in that the polymer compound having an anionic functional group in the molecular chain is a linear anionic polymer compound that is a copolymer of acrylic acid and acrylamide. (1) to (3) to provide a filling material for ground preparation.

Further, in the present invention (5), the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the montmorillonite particles (polymer compound having an anionic functional group in the molecular chain/montmorillonite particles) is The present invention provides a filling material for ground preparation according to any one of (1) to (4), characterized in that it is 0.020 to 0.50.

Further, the present invention (6) is characterized in that the mass ratio of the montmorillonite particles to the sand particles (montmorillonite particles/sand particles) is 0.010 to 0.20. It is to provide a filling material for ground preparation.

Further, in the present invention (7), the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the sand particle (polymer compound having an anionic functional group in the molecular chain/sand particle) is The present invention provides a filling material for ground preparation according to any one of (1) to (6), characterized in that it is 0.0050 to 0.020.

Further, in the present invention (8), the mass ratio of the montmorillonite particles to the water in the filler material for ground preparation (montmorillonite particles/water in the filler material for ground preparation) is 0.010 to 0.30. It provides a filling material for ground preparation according to any one of (1) to (7) characterized by

In addition, the present invention (9) is the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the water in the filling material for ground preparation (the polymer compound having an anionic functional group in the molecular chain /Water in the ground preparation filling material) is 0.0050 to 0.025.

According to the present invention, it is to provide a filling material for filling various cavities, which has sufficient fluidity when driving a pressure pump and does not flow when pressure is not applied. Moreover, it is possible to provide a ground construction filling material that does not separate in water and has high stability. In addition, since this filling material is mainly made of sand, it does not exhibit high strength.

1 is a SEM photograph (100 times) of a cross section of the filling material for ground preparation of Example 1. FIG. 1 is a SEM photograph (200 times) of a cross section of the filling material for ground preparation of Example 1. FIG.

The ground preparation filling material of the present invention contains at least sand particles, montmorillonite particles, a polymer compound having an anionic functional group in its molecular chain, and water,
The deformability in the texture test is 0.700 or more,
The attenuation property in the texture test is 0.700 or more,
It is a filling material for ground preparation characterized by
Further, the filling material for ground preparation of the present invention preferably has a series elastic modulus E1 of 900 Pa or more, a parallel elastic modulus E2 of 1,000 Pa or more, and a parallel section viscosity η1 of 10,000 Pa s or more, A series portion viscosity η2 is 200,000 Pa·s or more.
In addition, the ground preparation filling material of the present invention preferably has a supernatant turbidity of 50 or less in a water drop test.

The ground preparation filling material of the present invention contains at least sand particles, montmorillonite particles, a polymer compound having an anionic functional group in its molecular chain, and water.

The sand particles are not particularly limited, and may be, for example, sand, sand containing silt or gravel, crushed stone and slag, soil generated on site, and the like. The particle size of the sand particles is not particularly limited, and preferably the particle size is mainly about 0.074 to 2.0 mm, and the maximum particle size is preferably 9.5 mm or less.

A montmorillonite particle is a layered stack of a plurality of montmorillonite unit crystals. This montmorillonite unit crystal consists of a tetrahedral sheet in which tetrahedrons formed by silicon atoms and oxygen atoms are linked in a sheet form, and an octahedral sheet in which octahedrons of aluminum atoms and hydroxyl groups are linked in a sheet form. , has a sandwich structure in which one octahedral sheet is sandwiched between two tetrahedral sheets.

The montmorillonite particles have a tabular shape and a diameter of about 5 to 10 μm when saturated with water.

A montmorillonite unit crystal is a main component of bentonite, acid clay, and the like. Bentonite is a kind of tuff, and is a rock composed mainly of montmorillonite that has undergone chemical changes due to long-term thermal and stress changes. Bentonite is preferable as a raw material for the montmorillonite particles of the filling material for ground preparation of the present invention. As a raw material for the filling material for ground preparation of the present invention, bentonite pulverized into powder is preferably used.

The polymer compound having an anionic functional group in its molecular chain is not particularly limited as long as it has an anionic functional group in its molecular chain and can be electrostatically bonded to the side portions of the montmorillonite particles. Examples of polymer compounds having an anionic functional group in the molecular chain include homopolymers of acrylic acid, methacrylic acid, itaconic acid, maleic acid, acrylamido 2-methylpropanesulfonic acid, vinylsulfonic acid, styrenesulfonic acid, and the like. Alternatively, a copolymer of acrylamide with one or more of acrylic acid, methacrylic acid, itaconic acid, maleic acid, acrylamide 2-methylpropanesulfonic acid, vinylsulfonic acid and styrenesulfonic acid, and the like. For example, polymer compounds having an anionic functional group in the molecular chain include linear anionic polymer compounds that are copolymers of acrylic acid and acrylamide.

Although the molecular weight of the polymer compound having an anionic functional group in the molecular chain is not particularly limited, it is preferably 2,000,000 or more and 10,000,000 or less. The polymer compound having an anionic functional group in the molecular chain is in the form of a powdery acrylic polymer having an ionization degree of 0 to 100 mol % and a water-in-oil emulsion having a dispersed particle size of 100 μm or less. . Incidentally, the molecular weight of the polymer compound can be produced by a known method described in Japanese Patent Publication No. 34-10644.

The ground preparation filling material of the present invention contains water. Water exists in the gaps between the tabular aggregates of montmorillonite grains and is added to maintain the size of the gaps.

The deformability in the texture test of the filling material for ground preparation of the present invention is 0.700 or more, preferably 0.700 to 1.400, more preferably 0.800 to 1.350, particularly preferably 1.000 to 1. .350. When the deformability in the texture test of the filling material for ground preparation is within the above range, it has an elastic property of restoring its original shape without undergoing large deformation or breakage even when a load is applied. The ground preparation filling material of the present invention has high viscoelastic properties, so that it has sufficient fluidity at the time of placing, and when pressure does not act, it stays in place and has high filling properties. have. On the other hand, if the deformability in the texture test of the filling material for ground preparation is less than the above range, the material will deteriorate due to changes in pressure during construction, and the filling property will be impaired. There is a possibility that the reaction force against the pressure of time will be abnormally large and the workability will be lost.

The attenuation property in the texture test of the filling material for ground preparation of the present invention is 0.700 or more, preferably 0.700 to 1.200, more preferably 0.800 to 1.200, particularly preferably 1.000 to 1. .200. When the attenuation property in the texture test of the filling material for ground preparation is within the above range, it has an elastic property of restoring its original shape without undergoing large deformation or breakage even when a load is applied. The ground preparation filling material of the present invention has high viscoelastic properties, so that it has sufficient fluidity at the time of placing, and when pressure does not act, it stays in place and has high filling properties. have. On the other hand, if the attenuation property in the texture test of the filling material for ground preparation is less than the above range, the material will deteriorate due to changes in pressure during construction, and the filling property will be impaired. There is a possibility that the reaction force against the pressure of time will be abnormally large and the workability will be lost.

A texture test is a well-known test used for inspection of physical properties of foods and the like. At room temperature, fill the sample (filler) in a given container, set it in the test device, and then check the "deformability". (1st time), then, as in the first time, the cylinder is moved up and down at a constant speed, and the sample is penetrated and pulled out from the upper surface of the sample by 20 mm (2nd time), and the change curve of the test force is obtained. When confirming "damping property", first, the cylinder is moved up and down at a constant speed to penetrate and withdraw 4 mm from the upper surface of the sample (first time), and then this is repeated 9 times to measure the change in the test force. Ask. The "penetration stress" in the texture test is the penetration stress (Pa) obtained by converting the maximum load ha at the time of penetration into stress. In the texture test, each physical property value can be automatically displayed without drawing a change curve for each test.

In general, when a load (load) is applied to a sample, the sample is deformed or damaged. Regarding the "deformability" in the texture test, a load is applied twice in succession, and the ratio of the load area (energy) between the first time and the second time is defined as "deformability". Therefore, "deformability = 1" means that although the material is deformed the first time, it restores to its original shape and exhibits the same behavior the second time as well.
In addition, the "damping property" in the texture test is the ratio of the penetration stress (Pa) of each time to the penetration stress (Pa) of the first time (penetration stress 2nd / penetration stress 1 1st time, 3rd time penetration stress/1st time penetration stress, 4th time penetration stress/1st time penetration stress, . Therefore, "attenuation = 1" means that although it deforms at the first time, it restores to its original shape, and has an elastic property that exhibits the same behavior at the time of the ninth penetration.

The ground preparation filling material of the present invention has a series elastic modulus E1 of 900 Pa or more, preferably 1,500 Pa or more, and particularly preferably 2,000 Pa or more, and a parallel elastic modulus E2 of 1,000 Pa or more, preferably 1,000 Pa or more. It is 300 Pa or more, and particularly preferably 1,500 Pa or more. The parallel portion viscosity η1 of the ground preparation filling material of the present invention is 10,000 Pa s or more, preferably 50,000 Pa s or more, and particularly preferably 60,000 Pa s or more, and the series portion viscosity η2 is 200. ,000 Pa·s or more, preferably 500,000 Pa·s or more, and particularly preferably 600,000 Pa·s or more.
Since the series elastic modulus E1, the parallel elastic modulus E2, the parallel section viscosity η1, and the series section viscosity η2 of the filling material for ground preparation are within the above ranges, even if a load is applied, the material will not be greatly deformed or damaged, and will not be damaged. It has the property of elasticity to restore its shape. The ground preparation filling material of the present invention has high viscoelastic properties, so that it has sufficient fluidity at the time of placing, and when pressure does not act, it stays in place and has high filling properties. have. On the other hand, if the series elastic modulus E1, the parallel elastic modulus E2, the parallel section viscosity η1, or the series section viscosity η2 of the filling material for ground preparation are less than the above ranges, the material deteriorates due to the increase or decrease in pressure during construction, and the filling property may be damaged.

In the present invention, the elastic modulus E (Pa) and viscosity η (Pa s) of the filling material for ground preparation are measured using a viscoelasticity measuring device ARES-G2 manufactured by TA Instruments (JISK7132: 1999 “Rigid foam plastic specified load and temperature conditions The compression creep compliance J(t) in the compression creep test according to "Method for Measuring Compression Creep" in Section 4.3 Loading Apparatus) is determined from the Burgers model approximation.

The supernatant turbidity in the water drop test of the filling material for ground preparation of the present invention is 50 or less, preferably 20 or less. When the filler material for ground preparation has a supernatant turbidity in the water drop test, it is highly stable in water and does not easily separate in water even if dropped directly into water. On the other hand, if the supernatant turbidity in the water drop test of the filling material for ground preparation exceeds the above range, the stability against water is low, and if it is dropped directly into water, it will separate, or it will be separated due to the flow of water after filling. , diluted or lost.

In the present invention, the supernatant turbidity in the water drop test of the filling material for ground preparation is measured by putting 700 ml of tap water into a 1000 ml graduated cylinder at room temperature and setting a funnel with a minimum diameter of 40 mm at the opening. A mass of 12 ml (X) of Filler A1 is gravity-fed through a funnel into tap water. After dropping, the lump falls through the water, settles to the bottom and fills. After the filler is allowed to stand still, the volume (Y) of the lump is read to measure the fillability ((Y)/(X)). After that, 300 ml of the supernatant is collected, and the color tone of the turbid water is visually observed, and the turbidity is measured and confirmed by a turbidity meter (manufactured by Kyoritsu Rikagaku Kenkyusho; Model No. DPM2-TB500).

The filling property ((Y)/(X)) of the ground preparation filling material of the present invention is 1.00 to 1.20, preferably 1.00 to 1.10, and particularly preferably 1.00 to 1.05. is. When the filling property ((Y)/(X)) of the ground preparation filling material is within the above range, the filling materials are bonded to each other during filling, and the gaps between the filling materials can be filled by their own weight. , to obtain high fillability. On the other hand, if the filling property ((Y)/(X)) of the filling material for ground preparation is less than the above range, the volume after filling becomes smaller than the volume filled at the time of filling the cavity, so reliable filling is possible. Moreover, when the above range is exceeded, the gap formed during filling cannot be filled.

In the ground preparation filling material of the present invention, the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the montmorillonite particles (polymer compound having an anionic functional group in the molecular chain/montmorillonite particles) is preferably is 0.020 to 0.50, particularly preferably 0.17 to 0.19. When the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the montmorillonite particles (the polymer compound having an anionic functional group in the molecular chain/montmorillonite particles) is within the above range, the tabular shape of the montmorillonite particles is obtained. Bonds can be made and high elastic properties and stability in water can be obtained.

In the ground preparation filling material of the present invention, the mass ratio of montmorillonite particles to sand particles (montmorillonite particles/sand particles) is preferably 0.010 to 0.20, particularly preferably 0.060 to 0.080. When the mass ratio of montmorillonite to sand particles (montmorillonite particles/sand particles) is within the above range, the sand particles can be included in the layered structure composed of the tabular combination of montmorillonite particles, and the integral filler material can be obtained. becomes.

In the ground preparation filling material of the present invention, the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the sand particles (polymer compound having an anionic functional group in the molecular chain/sand particles) is preferably is 0.0050 to 0.020, particularly preferably 0.010 to 0.015. When the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the sand particles (polymer compound having an anionic functional group in the molecular chain/sand particle) is within the above range, the montmorillonite particles Sand grains can be included in the laminated structure of the flat plate-shaped composites, forming an integrated filler material.

In the filling material for ground preparation of the present invention, the mass ratio of montmorillonite particles to water (moisture in the filling material for ground preparation) (montmorillonite particles/water) is preferably 0.010 to 0.30, particularly preferably 0.30. 070 to 0.10. When the mass ratio of montmorillonite particles to water (montmorillonite particles/water) is within the above range, the filling material has a hardness that allows it to be applied.

In the filling material for ground preparation of the present invention, the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the water (moisture content in the filling material for ground preparation) (high (molecular compound/water) is preferably 0.0050 to 0.025, particularly preferably 0.013 to 0.019. When the mass ratio of the polymer compound having an anionic functional group in the molecular chain to water (the polymer compound having an anionic functional group in the molecular chain/water) is within the above range, the filling material can be applied. becomes hardness.

In addition to the above, the ground preparation filling material of the present invention can appropriately contain other components used in the ground preparation filling material. Other components appropriately contained in the ground preparation filler material of the present invention include, for example, dispersants such as polycarboxylate anionic surfactants.

The ground preparation filling material of the present invention has a tabular bond of montmorillonite grains formed by bonding montmorillonite grains. The tabular combination of montmorillonite grains has a tabular shape and is connected in a three-dimensional direction. It should be noted that connecting in a three-dimensional direction does not mean a structure in which flat plates spreading in two-dimensional directions are stacked in layers, but the sides of the flat-plate-shaped bonds spreading in two-dimensional directions are connected in other two-dimensional directions. It refers to a structure connected to the flat part of an expanding flat plate-like bond.

Further, in the ground preparation filling material of the present invention, the flat plate-shaped composite of montmorillonite grains covers the sand grains. In the ground preparation filling material of the present invention, the sand particles are covered with the flat plate-like combination of the montmorillonite particles that spread in the three-dimensional direction, so that the sand particles are held in the ground preparation filling material of the present invention. It is

In the ground preparation filling material of the present invention, the tabular combination of montmorillonite particles consists of montmorillonite particles and a polymer compound having an anionic functional group in the molecular chain. The side portions of the montmorillonite particles are reinforced by the positive charges existing on the side portions of the montmorillonite particles and the negative charges scattered on the molecular chains of the polymer compound having an anionic functional group in the molecular chains. Electrostatically binds to molecular chains of polymer compounds having anionic functional groups therein. As a result, a plurality of montmorillonite particles are bound via a polymer compound having an anionic functional group in the molecular chain to form a tabular combination of montmorillonite particles.

The ground preparation filling material of the present invention has high thixotropy and is excellent in placement into cavities. In addition, the ground preparation filling material of the present invention has high stability against water and excellent water impermeability. In addition, since this filling material is mainly made of sand, it does not exhibit high strength.

The method for producing the ground preparation filling material of the present invention is not particularly limited, and any production method may be used. An example of the method for producing the ground preparation filling material of the present invention is shown below, but the present invention is not limited to those produced by this method.

The method for producing the ground preparation filling material of the present invention includes, for example, a first step of mixing and stirring sand particles, bentonite powder (montmorillonite particles), and optionally water, and a first step. In the mixture (1) obtained by performing the second step of mixing and stirring adjusted water in which a dispersant is dissolved, and in the mixture (2) obtained by performing the second step, an anionic functional group in the molecular chain and a third step of mixing and stirring a polymer compound solution in which a polymer compound having is dissolved is mentioned.

Generally, sand particles are often wet, and such wet sand particles can be used as the sand particles in the first step. Further, in the first step, sand particles in a dry state or wet sand particles may be mixed with water in advance to be appropriately moistened, and used as the sand particles. Then, in the first step, sand particles moistened with water, bentonite powder, and optionally water are mixed and stirred for, for example, 60 to 120 seconds to diffuse the bentonite powder in the sand particles. . As for the mixing ratio of sand particles and bentonite powder, the mass ratio of bentonite powder to sand particles (excluding water) (bentonite powder/sand particles) is preferably 0.010 to 0.20, more preferably 0.050 to The mixing ratio is 0.090, particularly preferably 0.060 to 0.080.

The dispersant used in the second step is the same as the dispersant used in the ground construction filling material of the present invention. In the second step, a dispersant is dissolved in conditioned water in advance to prepare conditioned water in which the dispersant is dissolved, and the conditioned water in which the dispersant is dissolved in the mixture (1) obtained by performing the first step and agitated, for example, for 60-240 seconds. The content of the dispersant in the conditioned water in which the dispersant is dissolved is appropriately selected, but the content of the dispersant is preferably 0.1 to 1.5% by mass. In the second step, the mixed amount of the mixture (1) and the adjustment water in which the dispersant is dissolved is the mass ratio of the bentonite powder to the adjustment water (excluding the dispersant) (bentonite powder/water in the filler material for ground preparation ) is preferably 0.010 to 0.30, more preferably 0.030 to 0.12, and particularly preferably 0.070 to 0.10.

The polymer compound having an anionic functional group in the molecular chain for the third step is the same as the polymer compound having an anionic functional group in the molecular chain for the filling material for ground construction of the present invention. The content of the polymer compound having an anionic functional group in the molecular chain in the polymer compound solution relating to the third step is appropriately selected, but is preferably 0.5 to 15.0% by mass. In the third step, the polymer compound solution is mixed with the mixture (2) obtained by performing the second step, and stirred for 60 to 360 seconds, for example. In the third step, the mixing amount of the polymer compound is determined by dissolving the amount of water mixed in the first step (including the water contained in the sand particles before mixing) and the dispersant mixed in the second step. The mass ratio of the polymer compound to the sum of the water content in the adjusted water and the water content in the polymer compound solution (polymer compound / total water content used in the first step, second step and third step) However, the mixing amount is preferably 0.0050 to 0.025, more preferably 0.011 to 0.021, and particularly preferably 0.013 to 0.019. In addition, the amount of the polymer compound mixed is such that the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the bentonite powder (polymer compound/montmorillonite particles) is preferably 0.020 to 0.50, or more. The mixing amount is preferably 0.13 to 0.24, particularly preferably 0.17 to 0.19. In addition, regarding the amount of the polymer compound mixed, the mass ratio of the polymer compound having an anionic functional group in the molecular chain to the sand particles (polymer compound/sand particle) is preferably 0.0050 to 0.020, or more. The mixing amount is preferably 0.0070 to 0.018, particularly preferably 0.010 to 0.015.

Then, the filling material for ground preparation of the present invention is obtained by performing the method for producing the filling material for ground preparation of the present invention.

The ground preparation filling material of the present invention may be prepared by an appropriate method and then placed directly into the ground to be ground preparation, or it may be obtained after mixing and stirring a cement solution. The mixture may be poured into the ground to be prepared.

The cement solution is obtained by dissolving a powdery cement solidifying material in water. In the present invention, the mixing ratio of the cement solidification material and the sand particles in the ground preparation filling material is not particularly limited and may be appropriately selected, but is usually 50:1000 to 150:1000.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited thereto.

(Example 1)
(First step)
Aso sand (water content: 10.8% by mass, mountain sand from Ibaraki Prefecture, soil particle density ρs: 2.692 g/cm ³ , fine particle content: 4.0%) was added to 1000 g of bentonite powder (manufactured by Hojun Co., Ltd., 70 g of dry sieve residue (10.0%/53 μm or less) were mixed and stirred for 60 seconds to obtain a mixture (1).
(Second step)
Next, 5.0 g of a dispersant (polycarboxylate anionic surfactant) was dissolved in 492 g of water to prepare adjusted water in which the dispersant was dissolved. Next, the mixture (1) obtained above was mixed with the adjusted water in which the dispersant was dissolved, and the mixture was stirred for 120 seconds to obtain a mixture (2).
(Third step)
Next, 12.8 g of a copolymer of acrylic acid and acrylamide (manufactured by Hymo Co., Ltd., product name SAVE-SP construction method additive L1) was dissolved in 200 g of water to prepare a polymer compound solution. Next, the mixture (2) obtained above was mixed with the total amount of the polymer compound solution and stirred for 300 seconds to obtain a filling material for ground preparation.
Next, SEM observation of the obtained filling material for ground preparation was performed, and SEM photographs were obtained. The results are shown in FIG. 1 (100 times) and FIG. 2 (200 times). In addition, viscoelastic modulus measurement, texture test, and water drop test were conducted. Table 1 shows the results.
Next, the following performance evaluations of the obtained filling materials for ground preparation were performed. Table 1 shows the results.

<Evaluation method>
(Scanning electron microscope observation (SEM))
Samples were pretreated with a procedure of 1 flash freezing, 2 freeze-drying, 3 sectioning of dried samples.
Then, using a scanning electron microscope (JSM-IT500HR, manufactured by JEOL Ltd.), measurement was performed under the conditions of signal SED, incident voltage of 3.0 kV, WD of 50.0 mm, and magnifications of 100 and 200 times.

(Elastic modulus E (Pa) and viscosity η (Pa s))
Compression creep compliance in compression creep test by TA Instruments' viscoelasticity measuring device ARES-G2 (JISK7132: 1999 "Method for measuring compression creep under specified load and temperature conditions" 4.3 load device) J ( The elastic modulus E (Pa) and the viscosity η (Pa·s) were obtained from Burgers model approximation of t).

(Texture test "deformability")
Using a texture testing device (manufactured by Yamaden Co., Ltd., desktop physical property measuring device), fill the sample (filler) in a predetermined container at room temperature, set it in the testing device, and then first move the cylinder up and down at a constant speed. Then, the cylinder is moved up and down at a constant speed in the same manner as the first time, and the penetration and withdrawal of 20 mm from the top surface of the sample are performed (second time), and the penetration stress (Pa), penetration energy (J/m ³ ), and deformability (A2/A1) were determined. The deformability (A2/A1) refers to the ratio of the load area (energy) between the first time and the second time.

(Texture test "Attenuation")
Using a texture testing device (manufactured by Yamaden Co., Ltd., desktop physical property measuring device), fill the sample (filler) in a predetermined container at room temperature, set it in the testing device, and then first move the cylinder up and down at a constant speed. Then, the cylinder is moved up and down at a constant speed in the same way as the first time, and the penetration and withdrawal of 4 mm from the top surface of the sample are performed (second time), and the penetration stress (Pa), penetration energy (J/m ³ ), and penetration stress ratio (second penetration stress/first penetration stress) were obtained. This operation was repeated 9 times. Next, the ratio of the penetration stress (Pa) for each time to the penetration stress (Pa) for the first time (2nd penetration stress / 1st penetration stress, 3rd penetration stress / 1st penetration stress, 4th penetration stress / 1 penetration stress 9th time, .

(Water drop test)
At room temperature, put 700 ml of tap water in a 1000 ml graduated cylinder, set a funnel with a minimum diameter (40 mm) at the opening, and put 402.12 ml (X) of filler A1 lumps through the funnel into the tap water. Gravity dropped. After dropping, the mass fell through the water and settled and filled the bottom. After the filler was allowed to stand still, the volume (Y) of the lump was read to measure the fillability ((Y)/(X)). In addition, 300 ml of the supernatant was sampled, and the color tone of the turbid water was visually observed, and the turbidity was measured with a turbidity meter (model number DPM2-TB500 manufactured by Kyoritsu Rikagaku Kenkyusho Co., Ltd.).

<Performance evaluation>
(Evaluation of casting performance into cavities)
The deformability in the texture test is 0.700 or more, the damping property in the texture test is 0.700 or more, the series elastic modulus E1 is 900 Pa or more, and the parallel elastic modulus E2 is 1,000 or more and Pa, In addition, when the parallel portion viscosity η1 is 10,000 Pa s or more and the serial portion viscosity η2 is 200,000 Pa s or more, the performance of casting into the cavity is evaluated as "good", and the deformation in the texture test If any one of the properties, damping property in the texture test, series elastic modulus E1, and parallel elastic modulus E2 does not satisfy the above range, the casting performance into the cavity was evaluated as "poor".
(Underwater stability evaluation)
When the supernatant turbidity in the water dropping test was 50 or less, the stability in water was evaluated as "good", and when the supernatant turbidity in the water dropping test exceeded 50, the stability in water was evaluated as "poor".

(Examples 2-3, Comparative Examples 1-2)
The same procedure as in Example 1 was carried out, except that the mixing amount of each compounding material was as shown in Table 1. A stability evaluation was performed. Table 1 shows the results.

As shown in FIG. 1, the ground preparation filler material of Example 1 has a tabular bond of montmorillonite grains formed by bonding montmorillonite grains. The tabular combination of montmorillonite grains has a tabular shape and is connected in a three-dimensional direction. Also, tabular aggregates of montmorillonite grains cover the sand grains. The sand particles are held in the ground preparation filling material of the present invention by covering the sand particles with the flat plate-like aggregates of the montmorillonite particles that spread in the three-dimensional direction.

Claims (9)

containing at least sand particles, montmorillonite particles, a polymer compound having an anionic functional group in its molecular chain, and water,
The deformability in the texture test is 0.700 or more,
The attenuation property in the texture test is 0.700 or more,
A filling material for ground preparation, characterized by: The series elastic modulus E1 is 900 Pa or more, the parallel elastic modulus E2 is 1,000 Pa or more, the parallel portion viscosity η1 is 10,000 Pa s or more, and the series portion viscosity η2 is 200,000 Pa s or more. The filling material for ground preparation according to claim 1, characterized in that: 3. The filling material for ground preparation according to claim 1 or 2, having a supernatant turbidity of 50 or less in a water dropping test. Any one of claims 1 to 3, wherein the polymer compound having an anionic functional group in the molecular chain is a linear anionic polymer compound that is a copolymer of acrylic acid and acrylamide. Filling material for ground preparation according to paragraph. The mass ratio of the polymer compound having an anionic functional group in the molecular chain to the montmorillonite particles (polymer compound having an anionic functional group in the molecular chain/montmorillonite particles) is 0.020 to 0.50. The filling material for ground preparation according to any one of claims 1 to 4, characterized in that: The filling material for ground preparation according to any one of claims 1 to 5, wherein a mass ratio of the montmorillonite particles to the sand particles (montmorillonite particles/sand particles) is 0.010 to 0.20. The mass ratio of the polymer compound having an anionic functional group in the molecular chain to the sand particles (polymer compound having an anionic functional group in the molecular chain/sand particle) is 0.0050 to 0.020. The filling material for ground preparation according to any one of claims 1 to 6, characterized in that: Claims 1 to 7, characterized in that the mass ratio of the montmorillonite particles to the water in the filling material for ground preparation (montmorillonite particles/water in the filling material for ground preparation) is 0.010 to 0.30. The filling material for ground preparation according to any one of claims 1 to 3. Mass ratio of the polymer compound having an anionic functional group in the molecular chain to the water in the filling material for ground preparation (polymer compound having an anionic functional group in the molecular chain/water in the filling material for ground preparation ) is from 0.0050 to 0.025.

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