Method for reinforcing pressure plates and ground

Abstract

To provide a pressure plate capable of reinforcing the ground over a long term by densifying the installed location and its surroundings.SOLUTION: A disclosed pressure plate includes: a pressure plate body; and ion-releasing compounds capable of releasing cations or anions. The ion-releasing compounds are capable of generating poorly water-soluble salt.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pressure-bearing plate that can be used in ground. The present invention also relates to a ground reinforcement method using the above pressure-bearing plate.

Background Art

[0002] As a method for reinforcing ground to prevent the occurrence of rock slope failure and landslide, the ground anchor construction method is known. The ground anchor construction method is a construction method for stabilizing the slope by applying tension to a ground anchor anchored in stable ground, and transmitting this tension to a pressure-bearing plate (anchor panel) installed on the slope.

[0003] As a pressure-bearing plate, a pressure-bearing plate whose ground contact surface has a quadrilateral shape is known in order to increase the pressure-bearing area.

[0004] Patent Document 1 below discloses a pressure-bearing body that is attached to an anchor member erected on a slope and pressed against the slope. The pressure-bearing body has a main body layer composed of a thermosetting resin and a reinforcing layer including a fiber structure. In the pressure-bearing body, the powder of the thermosetting resin or another thermosetting resin is laminated on the fiber structure impregnated with the thermosetting resin, and the fiber structure and the thermosetting resin powder are compressed in a heated state, so that the main body layer and the reinforcing layer are integrated.

[0005] Further, Patent Document 2 below discloses a construction method for a slope frame using a pressure-bearing structure (pressure-bearing plate) including the following steps: a step of installing a plurality of pressure-bearing structures having hollow portions along the gradient direction and the lateral direction on the slope at predetermined intervals; a step of fixing each pressure-bearing structure to the slope with a ground anchor, and introducing tension to the ground anchor to introduce prestress to each pressure-bearing structure so as to press the slope; a step of integrally constructing a slope frame with the pressure-bearing structure between the respective pressure-bearing structures by cast-in-place concrete or precast concrete.

[0006] Furthermore, Patent Document 3 discloses a pressure-receiving plate for anchor construction, comprising a grounding base plate portion that can be made to contact with a slope, an anchor insertion portion formed in the grounding base plate portion for inserting an anchor member, an anchor locking portion formed in the anchor insertion portion for locking the anchor member, and a peripheral vertical reinforcing plate portion erected along the peripheral edge of the grounding base plate portion. In this pressure-receiving plate for anchor construction, the grounding base plate portion has drainage holes that form a passage for communication with the outside to the recess surrounded by the grounding base plate portion and the peripheral vertical reinforcing plate portion. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2006-328730 [Patent Document 2] Japanese Patent Application Publication No. 03-161615 [Patent Document 3] Japanese Patent Publication No. 2002-348866 [Overview of the project] [Problems that the invention aims to solve]

[0008] When conventional pressure plates are used to reinforce the ground, they can compress the ground, which can prevent, to some extent, the occurrence of slope failures and landslides.

[0009] However, with conventional pressure plates, if cracks or voids occur in the ground where the pressure plate is installed due to external stresses such as earthquakes, or changes in environmental conditions such as rainwater and groundwater, the pressure plate cannot adequately compress the ground, requiring further reinforcement.

[0010] Furthermore, in the anchoring method pressure plate described in Patent Document 3, by providing the drainage holes mentioned above, the planting function of vegetation is enhanced, which not only improves the landscape of the natural ground but is also expected to have the effect of strengthening the ground through planting. However, this effect is unstable because it depends on the plants.

[0011] Conventionally, no pressure-receiving plate capable of self-healing or strengthening the ground over a long period of time has been known.

[0012] The object of the present invention is to provide a pressure-receiving plate that can densify the ground at the installation site and its surroundings, thereby reinforcing the ground over the long term. Another object of the present invention is to provide a method for reinforcing the ground using the above-mentioned pressure-receiving plate. [Means for solving the problem]

[0013] This specification discloses the following pressure plate and ground reinforcement method.

[0014] Item 1. A pressure plate comprising a pressure plate body and an ion-releasing compound capable of releasing cations or anions, wherein the ion-releasing compound is capable of generating a poorly water-soluble salt.

[0015] Item 2. The pressure plate according to Item 1, wherein the poorly water-soluble salt is calcium carbonate, barium carbonate, calcium phosphate, or iron hydroxide.

[0016] Item 3. The pressure plate according to Item 1 or 2, wherein the ion-releasing compound comprises a compound capable of releasing cations, and the compound capable of releasing cations is calcium silicate, tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, barium lactate, calcium sulfate, calcium chloride, calcium nitrate, or calcium bicarbonate.

[0017] Item 4. The pressure plate according to any one of items 1 to 3, wherein the ion-releasing compound comprises a compound capable of releasing anions, and the compound capable of releasing anions is sodium hydrogen phosphate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, or calcium bicarbonate.

[0018] Item 5. The pressure receiving plate according to any one of Items 1 to 4, wherein a surface of the ion-releasing compound is coated with a coating agent.

[0019] Item 6. The pressure receiving plate according to any one of Items 1 to 5, wherein the pressure receiving plate main body includes a urethane resin body containing long fibers, fiber-reinforced plastic, a hardened product of cement milk, a hardened product of mortar, or a hardened product of concrete.

[0020] Item 7. A ground reinforcement method for reinforcing ground using a ground anchor and the pressure receiving plate according to any one of Items 1 to 6.

[0021] Item 8. The ground reinforcement method according to Item 7, wherein the pressure receiving plate main body includes a hardened product of cement milk or a hardened product of mortar. Effects of the Invention

[0022] The pressure receiving plate according to the present invention includes a pressure receiving plate main body and an ion-releasing compound capable of releasing cations or anions, and the ion-releasing compound is capable of generating a poorly water-soluble salt. Since the pressure receiving plate according to the present invention has the above configuration, it is possible to densify the installed location and its surroundings, and reinforce the ground over a long period of time. Brief Description of the Drawings

[0023] [Figure 1] Figures 1(a) and 1(b) are a plan view and a front view showing a pressure receiving plate according to a first embodiment of the present invention. [Figure 2] Figures 2(a) and 2(b) are a plan view and a front view showing a pressure receiving plate according to a second embodiment of the present invention. [Figure 3] Figures 3(a) and 3(b) are a plan view and a front view showing a pressure receiving plate according to a third embodiment of the present invention. Modes for Carrying Out the Invention

[0024] Hereinafter, the details of the present invention will be described.

[0025] (Pressure plate) The pressure plate according to the present invention comprises a pressure plate body and an ion-releasing compound (hereinafter sometimes referred to as "ion-releasing compound") capable of releasing cations or anions. In the pressure plate according to the present invention, the ion-releasing compound is capable of generating a poorly water-soluble salt.

[0026] In this specification, "poorly water-soluble salt" means a salt in which, when 1 g of the poorly water-soluble salt is placed in 100 g of water and kept at 20°C for 10 minutes, the weight of the poorly water-soluble salt that dissolves in water is 0.1 g or less.

[0027] The pressure plate according to the present invention has the above-described configuration, which allows for increased strength at the installation site and its surroundings, and enables the maintenance of high strength over a long period of time. More specifically, at the installation site and its surroundings of the pressure plate according to the present invention, the ion-releasing compound in the pressure plate releases ions, generating poorly water-soluble salts and forming concretion. As a result, the installation site and its surroundings are densified, and the ground can be reinforced over the long term. The present invention contributes to the preventive maintenance of the ground.

[0028] In the pressure plate according to the present invention, when the pressure plate comes into contact with moisture adhering to the ground or the like at the location where the pressure plate is installed, the ion-releasing compound in the pressure plate releases ions, thereby generating a poorly water-soluble salt at the contact surface between the moisture and the pressure plate. In other words, the pressure plate according to the present invention can generate a layer of poorly water-soluble salt on its surface. The generated poorly water-soluble salt further enhances the strength of the installation location and its surroundings. It is generally believed that the poorly water-soluble salt is generated over a period of several months to several years. Furthermore, the generated poorly water-soluble salt effectively suppresses further contact between the pressure plate and moisture, thereby effectively suppressing deterioration of the pressure plate and erosion of the ground.

[0029] Furthermore, the pressure plate according to the present invention can be used whether the installation location is dry or wet. Moreover, the pressure plate according to the present invention can be used even if water is flowing out from the installation location.

[0030] The above-mentioned pressure plate is suitably used to reinforce the ground. The above-mentioned pressure plate is particularly suitably used to reinforce slopes (embankments). The above-mentioned pressure plate is preferably a slope (embankment) pressure plate that reinforces slopes (embankments).

[0031] The inclination angle of the slope on which the above-mentioned pressure plate can be used is not particularly limited. The inclination angle of the slope may be greater than 0°, 30° or more, 45° or more, 90° or less, 75° or less, or 60° or less.

[0032] The shape of the pressure-receiving plate is not particularly limited. Examples of the shape of the pressure-receiving material include cross type, semi-square type, or square type. From the viewpoint of improving the density of the ground at the contact surface, the shape of the pressure-receiving material is preferably square type.

[0033] Figures 1(a) and 1(b) are a plan view and a front view showing a pressure receiving plate according to the first embodiment of the present invention.

[0034] The pressure plates shown in Figures 1(a) and (b) are cross-type pressure plates. The dimensions A, B, L, C, H, and H1 in Figure 1 can be set as appropriate according to the required size and specifications for the pressure plate.

[0035] Figures 2(a) and 2(b) are a plan view and a front view showing a pressure receiving plate according to a second embodiment of the present invention.

[0036] The pressure plates shown in Figures 2(a) and (b) are semi-square type pressure plates. The dimensions A, B, L, C, H, H1, and H2 in Figure 2 can be set as appropriate according to the required size and specifications for the pressure plate.

[0037] Figures 3(a) and 3(b) are a plan view and a front view showing a pressure receiving plate according to a third embodiment of the present invention.

[0038] The pressure plates shown in Figures 3(a) and (b) are square-type pressure plates. The dimensions A, B, L, C, H, H1, and H2 in Figure 3 can be set as appropriate according to the required size and specifications for the pressure plate.

[0039] From the viewpoint of improving workability and reaction force, the weight of one member of the above-mentioned pressure receiving plate is preferably 0.1t or more, more preferably 0.2t or more, even more preferably 0.5t or more, preferably 2t or less, more preferably 1.5t or less, and even more preferably 1t or less.

[0040] From the viewpoint of improving workability (reducing the number of units to be installed per unit area), the pressure-receiving area of ​​the above-mentioned pressure-receiving plate is preferably 1 m². 2 More than 2m 2 More preferably 3m 2 The above is preferable to 10m 2 More preferably 8m 2 Further preferably 6m 2 The following applies:

[0041] The pressure-receiving plate is fixed in combination with a ground anchor. Preferably, the pressure-receiving plate is anchored by the driven ground anchor. The pressure-receiving plate is preferably used to press and hold the ground with the tension force of the ground anchor. The ground anchor is not particularly limited. Known ground anchors can be used as the ground anchor.

[0042] The details of the pressure plate according to the present invention will be described below.

[0043] <Pressure plate body> The pressure plate body may preferably contain a urethane resin body containing long fibers, fiber-reinforced plastic, hardened cement grout, hardened mortar, or hardened concrete, and more preferably contains hardened cement grout or hardened mortar. The pressure plate body may contain a urethane resin body containing long fibers, fiber-reinforced plastic, hardened cement grout, hardened mortar, or hardened concrete. The material of the pressure plate body may contain long fibers, polyol compounds, and isocyanate compounds, fibers, and plastic (resin), cement grout, mortar, or concrete. Furthermore, the hardened concrete may contain reinforcing bars or iron fibers.

[0044] [Urethane resin body containing long fibers] The pressure plate body preferably contains a urethane resin body containing long fibers (hereinafter sometimes referred to as "urethane resin body"). The material of the pressure plate body preferably contains long fibers, a polyol compound, and an isocyanate compound. When the pressure plate body contains a urethane resin body containing long fibers, that is, when the material of the pressure plate body contains long fibers, a polyol compound, and an isocyanate compound, corrosion resistance when used outdoors and processability (assembly) when manufacturing the pressure plate can be improved.

[0045] The above-mentioned urethane resin body can be obtained by molding the material of the pressure plate body. From the viewpoint of improving the rigidity and strength of the pressure plate, the above-mentioned urethane resin body is preferably a urethane foam resin body (a urethane foam resin body containing long fibers). From the viewpoint of improving workability (reducing weight), the above-mentioned urethane resin body is preferably a foam of urethane resin.

[0046] Examples of the long fibers mentioned above include carbon long fibers, glass long fibers, aramid long fibers, and long reinforced fibers. Only one type of long fiber may be used, or two or more types may be used in combination.

[0047] The long fibers described above are preferably reinforced long fibers. Reinforced long fibers are reinforcing fibers and long fibers. Reinforcing fibers are fibrous materials having a certain strength. Examples of reinforcing fibers include carbon fibers, glass fibers, and aramid fibers. The reinforced long fibers described above may also be reinforced long fiber sheets.

[0048] From the viewpoint of increasing the flexural modulus of the pressure plate, the reinforcing long fibers are preferably glass long fibers. The glass long fibers are fibrous materials obtained by melting and stretching glass.

[0049] From the viewpoint of further increasing strength, the fiber length of the long fibers is preferably 50 mm or more, and more preferably 70 mm or more. The long fibers can be cut to the desired size after pultrusion, and the fiber length of the long fibers can be appropriately changed depending on the length to be cut. Therefore, there is no particular upper limit to the fiber length of the long fibers. From the viewpoint of improving dimensional accuracy, the fiber length of the long fibers may be 10 m or less. Furthermore, even if the fiber length of the long fibers is long, impregnating the long fibers with a composition containing components other than long fibers can make it less likely for the long fibers to be cut or entangled. In addition, pultrusion allows for molding even with a high proportion of long fibers.

[0050] The above-mentioned long fibers are preferably fibers obtained by aligning and roving monofilaments. The fiber diameter of the above-mentioned monofilaments is preferably 1 μm or more, more preferably 2 μm or more, more preferably 50 μm or less, and more preferably 40 μm or less.

[0051] In 100% by volume of the above urethane resin body, the content (volume content) of the above long fibers is preferably 3% by volume or more, more preferably 5% by volume or more, preferably 80% by volume or less, and more preferably 50% by volume or less. When the content of the above long fibers is above the lower limit and below the upper limit, the bending modulus of the pressure plate can be increased.

[0052] The volume content of the above-mentioned long fibers can be determined in accordance with the firing method described in JIS K7052.

[0053] It is preferable that the long fibers described above are evenly dispersed in the urethane resin body.

[0054] A urethane resin body containing long fibers can be obtained by impregnating the long fibers with a composition of the pressure plate body (urethane resin body) material, excluding the long fibers, between the long fibers and then curing it.

[0055] When the pressure plate body includes a urethane resin body containing long fibers, the method for manufacturing the pressure plate is not particularly limited. The method for manufacturing the pressure plate may include (1) a step of mixing a polyol compound, an isocyanate compound, and the ion-releasing compound to obtain an impregnation liquid, (2) a step of impregnating the long fibers with the impregnation liquid, and (3) a step of curing the polyol compound and the isocyanate compound in the impregnation liquid.

[0056] In 100% by weight of the pressure-receiving plate body, the content of the long fibers is preferably 10% by weight or more, more preferably 20% by weight or more, preferably 80% by weight or less, more preferably 70% by weight or less, and even more preferably 60% by weight or less. If the content of the long fibers is above the lower limit, the bending modulus of the pressure-receiving plate becomes even higher. Also, if the content of the long fibers is below the upper limit, it becomes less likely that there will be parts of the composition of the pressure-receiving plate body that are not impregnated with long fibers, and defects that cause damage to the pressure-receiving plate become less likely to occur.

[0057] Examples of the above polyol compounds include polylactone polyols, aromatic polyols, alicyclic polyols, polyester polyols, and polyether polyols. The above polyol compounds may be used individually or in combination of two or more.

[0058] From the viewpoint of improving the moldability of the pressure plate shape, the polyol compound is preferably a polyester polyol or a polyether polyol, and more preferably a polyether polyol.

[0059] The viscosity of the above polyol compound at 23°C is preferably 100 mPa·s or more, more preferably 200 mPa·s or more, preferably 1500 mPa·s or less, and more preferably 1000 mPa·s or less. When the viscosity of the above polyol compound at 23°C is above the lower limit and below the upper limit, the flexural modulus of the pressure plate can be increased.

[0060] The viscosity of the above polyol compound at 23°C can be measured, for example, using a Brookfield viscometer.

[0061] The above isocyanate compound is preferably a polyisocyanate compound. Examples of the above polyisocyanate compound include aromatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and aliphatic polyisocyanate compounds. The above polyisocyanate compound may be used alone or in combination of two or more.

[0062] Examples of the above aromatic polyisocyanate compounds include phenylenediisocyanate, tolylenediisocyanate, xylylenediisocyanate, diphenylmethanediisocyanate, dimethyldiphenylmethanediisocyanate, triphenylmethanetriisocyanate, naphthalenediisocyanate, and polymethylenepolyphenylpolyisocyanate.

[0063] Examples of the above-mentioned alicyclic polyisocyanate compounds include cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and dimethyldicyclohexylmethane diisocyanate.

[0064] Examples of the above-mentioned aliphatic polyisocyanate compounds include methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate.

[0065] Because it is readily available and offers excellent convenience, the above isocyanate compound is preferably diphenylmethane diisocyanate.

[0066] The above polyol compound and the above isocyanate compound can be used in appropriate proportions to efficiently form urethane bonds.

[0067] The isocyanate index is defined as the ratio of the total number of isocyanate groups in the isocyanate compound to the total number of active hydroxyl groups in the polyol compound (total number of isocyanate groups in the isocyanate compound × 100 / total number of active hydroxyl groups in the polyol compound). The isocyanate index is preferably 120 or higher, more preferably 200 or higher, preferably 1000 or lower, and more preferably 600 or lower. When the isocyanate index is above the lower limit, the isocyanurate ring, which is the framework exhibiting high flame retardancy, is formed more effectively, thereby increasing the flame retardancy of the pressure plate. When the isocyanate index is below the upper limit, the formation of the isocyanurate ring can be effectively stopped, thereby increasing the flexural modulus of the pressure plate. Furthermore, when the isocyanate index is above the lower limit and below the upper limit, the reaction efficiency between the polyol compound and the isocyanate compound can be increased. Furthermore, if the isocyanate index is above the lower limit, the amount of unreacted polyol compounds or unreacted isocyanate compounds decreases, making it easier to form a pressure-receiving plate with a good flexural modulus.

[0068] The material of the pressure plate body preferably contains a catalyst. Examples of catalysts include urethane catalysts and trimerizing catalysts. Only one type of catalyst may be used, or two or more types may be used in combination.

[0069] The material of the pressure plate body preferably contains a urethane catalyst. The urethane catalyst promotes the reaction between the hydroxyl group of the polyol compound and the isocyanate group of the isocyanate compound, thereby promoting the formation of urethane bonds.

[0070] Examples of the above urethane catalysts include organotin compounds such as dibutyltin dimalate, dibutyltin diurarate, and dibutylbis(oleoyloxy) stannan; tertiary amine compounds such as triethylamine, N-methylmorpholine bis(2-dimethylaminoethyl) ether, and N,N,N',N'',N''-pentamethyldiethylenetriamine; N,N,N'-trimethylaminoethyl-ethanolamine, bis(2-dimethylaminoethyl) ether, N-methyl,N'-dimethylaminoethylpiperazine; and imidazole compounds in which the secondary amine functional group in the imidazole ring is substituted with a cyanoethyl group. The above urethane catalysts may be used individually or in combination of two or more.

[0071] The above urethane catalyst can be used in an appropriate amount so that the polyol compound and the isocyanate compound react well. The content of the urethane catalyst per 100 parts by weight of the polyol compound is preferably 0.01 parts by weight or more, more preferably 0.02 parts by weight or more, preferably 1.0 part by weight or less, and more preferably 0.8 parts by weight or less. If the content of the urethane catalyst is above the lower limit, the urethane reaction proceeds effectively. If the content of the urethane catalyst is below the upper limit, the trimerization of the isocyanate group of the isocyanate compound is less likely to be inhibited.

[0072] The above trimerization catalyst promotes the trimerization reaction of the isocyanate group in isocyanate compounds, thereby facilitating the formation of isocyanurate rings. Furthermore, the above trimerization catalyst suppresses the expansion of the urethane resin during combustion.

[0073] Examples of the above-mentioned trimerization catalysts include aromatic compounds, alkali metal salts of carboxylic acids, quaternary ammonium salts of carboxylic acids, and quaternary ammonium salt / ethylene glycol mixtures. Examples of the above-mentioned aromatic compounds include tris(dimethylaminomethyl)phenol, 2,4-bis(dimethylaminomethyl)phenol, and 2,4,6-tris(dialkylaminoalkyl)hexahydro-S-triazine. Examples of the above-mentioned alkali metal salts of carboxylic acids include potassium acetate and potassium 2-ethylhexanoate. The above-mentioned trimerization catalysts may be used individually or in combination of two or more types.

[0074] The above trimerizing catalyst can be used in an appropriate amount so as to promote the trimerizing reaction well. The amount of the trimerizing catalyst per 100 parts by weight of the polyol compound is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, preferably 1.0 part by weight or less, and more preferably 0.8 parts by weight or less. If the amount of the trimerizing catalyst is above the lower limit, it is easier to suppress the expansion of the urethane resin during the formation of the urethane resin. If the amount of the trimerizing catalyst is below the upper limit, the formation of urethane bonds is less likely to be inhibited.

[0075] From the viewpoint of obtaining a urethane foam resin body, it is preferable that the material of the pressure plate body contains a foaming agent. By foaming the material of the pressure plate body with a foaming agent, a urethane foam resin body can be obtained. As a result, workability (reduced weight) can be improved.

[0076] Examples of the foaming agents mentioned above include water and organic halogen compounds. Water is preferred as the foaming agent because it is readily available and convenient. Water acts as a foaming agent by reacting with isocyanate compounds to generate CO2. Only one type of foaming agent may be used, or two or more types may be used in combination.

[0077] Examples of the above-mentioned organic halogen compounds include organic chlorine compounds, organic fluorine compounds, organic bromine compounds, and organic iodine compounds. The above-mentioned organic halogen compounds may be organic halogen compounds in which all hydrogen atoms are replaced by halogen atoms, or organic halogen compounds in which some of the hydrogen atoms are replaced by halogen atoms. From the viewpoint of improving foaming properties and maintaining a low thermal conductivity of the pressure plate over a long period of time, the above-mentioned organic halogen compounds are preferably organic chlorine compounds or organic fluorine compounds.

[0078] Examples of the above-mentioned organochlorine compounds include saturated organochlorine compounds and unsaturated organochlorine compounds. Examples of the above-mentioned saturated organochlorine compounds include dichloroethane, propyl chloride, isopropyl chloride, butyl chloride, isobutyl chloride, pentyl chloride, and isopentyl chloride. From the viewpoint of improving foaming properties and maintaining a low thermal conductivity of the pressure plate over a long period of time, the above-mentioned organochlorine compounds are preferably saturated organochlorine compounds, and more preferably saturated organochlorine compounds having 2 to 5 carbon atoms.

[0079] Examples of the above-mentioned organofluorine compounds include saturated organofluorine compounds and unsaturated organofluorine compounds.

[0080] From the viewpoint of improving foaming properties and maintaining a low thermal conductivity of the pressure plate over a long period of time, the above-mentioned organic halogen compound is preferably a hydrochlorofluoroolefin, a hydrofluorocarbon, or a hydrofluoroolefin.

[0081] The foaming ratio is preferably 1.5 or higher, and preferably less than 3.0. If the foaming ratio is above the lower limit, the weight of the urethane foam resin body will be reduced, making it easier to handle. If the foaming ratio is below the upper limit, the decrease in strength of the urethane foam resin body will be suppressed.

[0082] Furthermore, the material of the pressure plate body may contain foam stabilizers and the like, to the extent that it does not hinder the purpose of the present invention. Only one type of foam stabilizer may be used, or two or more types may be used in combination.

[0083] The foam stabilizer mentioned above is a substance that prevents the coarsening and uneven formation of bubbles, and enables the stable and effective formation of bubbles.

[0084] Examples of the foam stabilizers mentioned above include polyoxyalkylene foam stabilizers such as polyoxyalkylene alkyl ethers, and silicone foam stabilizers such as organopolysiloxanes.

[0085] The foam stabilizer described above can be used in an appropriate amount to ensure stable and good bubble formation. From the viewpoint of stable and good bubble formation, the amount of the foam stabilizer described above per 100 parts by weight of the polyol compound is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, even more preferably 0.2 parts by weight or more, preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and even more preferably 1 part by weight or less.

[0086] [Fiber-reinforced plastic (FRP)] The pressure plate body preferably contains fiber-reinforced plastic (FRP). In the fiber-reinforced plastic, resin is impregnated into the fibers. When the pressure plate body contains fiber-reinforced plastic, its rigidity, strength, and corrosion resistance can be improved.

[0087] From the viewpoint of improving workability, it is preferable that the fiber-reinforced plastic described above be in the shape of a single pressure-receiving plate.

[0088] Examples of the fiber-reinforced plastics mentioned above include glass fiber reinforced plastics (GFRP), carbon fiber reinforced plastics (CFRP), aramid fiber reinforced plastics (AFRP), and natural fiber reinforced plastics (NFRP).

[0089] From the viewpoint of improving cost-effectiveness, the fiber-reinforced plastic is preferably glass fiber-reinforced plastic. From the viewpoint of improving surface strength, it is preferable that the glass fiber base material of the fiber-reinforced plastic is impregnated with resin.

[0090] Examples of the above-mentioned fibers include glass fibers, carbon fibers, aramid fibers, and natural fibers.

[0091] From the viewpoint of improving cost-effectiveness, the above-mentioned fibers are preferably glass fibers. From the viewpoint of increasing the strength of the pressure plate, the above-mentioned glass fibers are preferably glass roving cloth or glass roving mat. The pressure plate body is preferably made of glass roving cloth or glass roving mat.

[0092] From the viewpoint of reducing manufacturing costs, the above fibers are preferably in the form of fiber bundles. The above fiber bundle is a bundle of multiple fibers. The above fiber bundle is, for example, a reinforcing fiber bundle. The elastic modulus of the fiber bundle, especially the elastic modulus of the reinforcing fiber bundle, is relatively high. The form of the above fiber bundle is not particularly limited. The above fiber bundle may be a fiber sheet formed by stitching or the like.

[0093] The number of fibers in the fiber bundle described above is not particularly limited. From the viewpoint of increasing the strength of the pressure plate, in the case of glass fibers, the number of fibers in the fiber bundle is preferably 100 or more, more preferably 200 or more, preferably 1000 or less, and more preferably 500 or less. In the case of carbon fibers, 1000 to 50000 fibers is preferred.

[0094] The above resin may be a thermoplastic resin or a cured product of a thermosetting resin. Only one type of resin may be used, or two or more types may be used in combination.

[0095] Examples of the thermoplastic resins mentioned above include polyolefin resins, polyamide resins, polycarbonate resins, polystyrene resins, and polyester resins.

[0096] Examples of the thermosetting resins mentioned above include unsaturated polyester resins, vinyl ester resins, epoxy resins, and phenolic resins.

[0097] The above-mentioned thermosetting resin may be used in combination with a thermosetting agent. From the viewpoint of increasing the strength of the pressure plate, it is preferable that the above-mentioned thermosetting resin be used in combination with a thermosetting agent.

[0098] From the viewpoint of increasing the strength of the pressure plate, the resin is preferably a cured product of a thermosetting resin. From the viewpoint of increasing the strength of the pressure plate, the thermosetting resin is more preferably an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, or a phenolic resin, even more preferably an unsaturated polyester resin or an epoxy resin, and particularly preferably an unsaturated polyester resin.

[0099] When the pressure plate body contains fiber-reinforced plastic, the method for manufacturing the pressure plate is not particularly limited. The method for manufacturing the pressure plate may include (1) a step of mixing the resin and the ion-releasing compound to obtain an impregnation liquid, (2) a step of impregnating the fibers in the fiber substrate with the impregnation liquid, and (3) a step of curing the resin in the impregnation liquid.

[0100] From the viewpoint of improving rigidity and strength, the fiber content in 100 volume percent of the pressure-receiving plate body is preferably 10 volume percent or more, more preferably 20 volume percent or more, preferably 65 volume percent or less, and more preferably 60 volume percent or less.

[0101] [Hardened cement milk, hardened mortar, and hardened concrete] The pressure plate body preferably contains a hardened cement grout, a hardened mortar, or a hardened concrete. The material of the pressure plate body preferably contains cement grout, mortar, or concrete.

[0102] When the pressure plate body contains hardened cement grout, that is, when the material of the pressure plate body contains cement grout, the viscosity when filling the pressure plate material into the installation area (frame) can be improved, and the pourability of the pressure plate material can be enhanced. When the pressure plate body contains hardened mortar or hardened concrete, that is, when the material of the pressure plate body contains mortar or concrete, shrinkage due to cement hardening (auto-shrinkage) and shrinkage due to drying after hardening (drying shrinkage) can be suppressed.

[0103] In this specification, "cement milk" means a mixture of cement and water (mixing water). In this specification, "cement milk" does not contain fine aggregate or coarse aggregate. In this specification, "mortar" means a mixture of cement, fine aggregate and water (mixing water). In this specification, "mortar" does not contain coarse aggregate. In this specification, "concrete" means a mixture of cement, fine aggregate, coarse aggregate and water (mixing water). In this specification, "cement" means a powder that can harden through a chemical reaction with water, mainly composed of limestone, clay, silica, and iron oxide raw materials.

[0104] The cement contained in the cement milk, mortar, and concrete is not particularly limited. Examples of cement contained in the cement milk, mortar, and concrete include Portland cement, blast furnace cement, silica cement, and fly ash cement. The cement may also be fiber-reinforced cement. The Portland cement may be ordinary Portland cement or special Portland cement (rapid-hardening Portland cement).

[0105] Examples of coarse aggregate include artificial aggregate and natural aggregate. Examples of artificial aggregate include blast furnace slag and fly ash. Examples of natural aggregate include gravel and crushed stone. Examples of gravel include river gravel, mountain gravel, sea gravel and volcanic gravel. From the viewpoint of improving material costs, it is preferable that the coarse aggregate is gravel.

[0106] The average particle size of the above-mentioned coarse aggregate is preferably 5 mm or more, more preferably 10 mm or more, preferably 2000 mm or less, and more preferably 100 mm or less. If the average particle size of the above-mentioned coarse aggregate is above the lower limit, the strength of the pressure plate can be increased. If the average particle size of the above-mentioned coarse aggregate is below the upper limit, the settling of the above-mentioned coarse aggregate can be suppressed, the viscosity when filling the material for the pressure plate into the installation area (within the frame) can be improved, and the injectability of the material for the pressure plate can be increased.

[0107] Examples of the fine aggregate mentioned above include artificial aggregates and natural aggregates. Examples of the artificial aggregates include blast furnace slag and fly ash. Examples of the natural aggregates include sand. From the viewpoint of improving material costs, it is preferable that the fine aggregate is sand.

[0108] The average particle size of the fine aggregate is preferably 0.01 mm or more, more preferably 0.1 mm or more, preferably 5 mm or less, and more preferably 4 mm or less. If the average particle size of the fine aggregate is above the lower limit, the strength of the pressure plate can be increased. If the average particle size of the fine aggregate is below the upper limit, the settling of the fine aggregate can be suppressed, the viscosity when filling the pressure plate material into the installation area (frame) can be improved, and the injectability of the pressure plate material can be increased.

[0109] When the pressure plate body contains a hardened cement milk, a hardened mortar, or a hardened concrete, the method for manufacturing the pressure plate is not particularly limited. The method for manufacturing the pressure plate may include (1) a step of mixing the cement milk, mortar, or concrete with the ion-releasing compound to obtain a mixture, and (2) a step of hardening the cement milk, mortar, or concrete.

[0110] From the viewpoint of exhibiting the effects of the present invention more effectively, the cement content in 100% by weight of the above cement milk is preferably 10% by weight or more, more preferably 20% by weight or more, even more preferably 30% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, and even more preferably 70% by weight or less.

[0111] In the above cement milk, the water (mixing water) content per 100 parts by weight of cement is preferably 11 parts by weight or more, more preferably 25 parts by weight or more, even more preferably 35 parts by weight or more, preferably 125 parts by weight or less, more preferably 100 parts by weight or less, and even more preferably 66 parts by weight or less. If the water (mixing water) content is above the lower limit, the cement and water (mixing water) can react well, and the strength of the pressure plate can be increased. If the water (mixing water) content is below the upper limit, the cement and water (mixing water) can be mixed uniformly, and the strength of the pressure plate can be increased.

[0112] From the viewpoint of exhibiting the effects of the present invention more effectively, the cement content in 100% by weight of the above mortar is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, preferably 60% by weight or less, more preferably 50% by weight or less, and even more preferably 40% by weight or less.

[0113] From the viewpoint of exhibiting the effects of the present invention more effectively, the content of fine aggregate in 100% by weight of the above mortar is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, preferably 90% by weight or less, more preferably 85% by weight or less, and even more preferably 80% by weight or less.

[0114] From the viewpoint of exhibiting the effects of the present invention more effectively, in the above mortar, the content of fine aggregate per 100 parts by weight of cement is preferably 11 parts by weight or more, more preferably 25 parts by weight or more, even more preferably 40 parts by weight or more, preferably 900 parts by weight or less, more preferably 400 parts by weight or less, and even more preferably 250 parts by weight or less.

[0115] In the above mortar, the water (mixing water) content per 100 parts by weight of cement is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, even more preferably 40 parts by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, and even more preferably 60 parts by weight or less. If the water (mixing water) content is above the lower limit, the cement and water (mixing water) can react well, and the strength of the pressure plate can be increased. If the water (mixing water) content is below the upper limit, the cement and water (mixing water) can be mixed uniformly, and the strength of the pressure plate can be increased.

[0116] From the viewpoint of exhibiting the effects of the present invention more effectively, the content of coarse aggregate in 100% by weight of the above concrete is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less.

[0117] From the viewpoint of exhibiting the effects of the present invention more effectively, the content of fine aggregate in 100% by weight of the above concrete is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, preferably 50% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less.

[0118] From the viewpoint of exhibiting the effects of the present invention more effectively, in the above concrete, the content of coarse aggregate per 100 parts by weight of cement is preferably 50 parts by weight or more, more preferably 100 parts by weight or more, even more preferably 200 parts by weight or more, preferably 500 parts by weight or less, more preferably 400 parts by weight or less, and even more preferably 300 parts by weight or less.

[0119] From the viewpoint of exhibiting the effects of the present invention more effectively, in the above concrete, the content of fine aggregate per 100 parts by weight of cement is preferably 50 parts by weight or more, more preferably 100 parts by weight or more, even more preferably 200 parts by weight or more, preferably 500 parts by weight or less, more preferably 400 parts by weight or less, and even more preferably 300 parts by weight or less.

[0120] From the viewpoint of exhibiting the effects of the present invention more effectively, in the above concrete, the water (mixing water) content per 100 parts by weight of cement is preferably 75 parts by weight or more, more preferably 100 parts by weight or more, even more preferably 125 parts by weight or more, preferably 200 parts by weight or less, more preferably 180 parts by weight or less, and even more preferably 160 parts by weight or less.

[0121] The content of the cement milk, mortar, or concrete in 100% by weight of the material of the pressure plate is preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, preferably 99.9% by weight or less, more preferably 99.5% by weight or less, and even more preferably 99% by weight or less. When the content of the cement milk, mortar, or concrete is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0122] The content of the cement milk, mortar, or concrete in 100% by weight of the material of the pressure plate body is preferably 85% by weight or more, more preferably 93% by weight or more, even more preferably 95% by weight or more, preferably 99.9% by weight or less, more preferably 99.5% by weight or less, and even more preferably 99% by weight or less. When the content of the cement milk, mortar, or concrete is above the lower limit and below the upper limit, the effects of the present invention can be exhibited even more effectively.

[0123] <Ion-releasing compounds> The pressure plate described above contains an ion-releasing compound (ion-releasing compound) capable of releasing cations or anions. The ion-releasing compound is capable of producing poorly water-soluble salts.

[0124] The above-mentioned ion-releasing compound may be a compound capable of releasing cations, a compound capable of releasing anions, a compound capable of releasing both cations and anions, or a mixture of a compound capable of releasing cations and a compound capable of releasing anions. The above-mentioned ion-releasing compound may contain a compound capable of releasing cations, a compound capable of releasing anions, or a compound capable of releasing cations and a compound capable of releasing anions. The above-mentioned ion-releasing compound may be used alone, or two or more may be used in combination.

[0125] It is preferable that the above-mentioned ion-releasing compound generates a poorly water-soluble salt upon contact with moisture adhering to the ground, etc. It is preferable that cations or anions are released from the above-mentioned ion-releasing compound by water or moisture reaching the location where the pressure plate is installed. Specifically, if the above-mentioned ion-releasing compound is a compound capable of releasing cations, it is preferable that the cations released from the above-mentioned ion-releasing compound react chemically with anions dissolved in moisture, etc., to form a poorly water-soluble salt. If the above-mentioned ion-releasing compound is a compound capable of releasing anions, it is preferable that the anions released from the above-mentioned ion-releasing compound react chemically with cations dissolved in moisture, etc., to form a poorly water-soluble salt. Furthermore, if the above-mentioned ion-releasing compound is a compound capable of releasing both cations and anions, or a mixture of a compound capable of releasing cations and a compound capable of releasing anions, it is preferable that the cations and anions released from the above-mentioned ion-releasing compound move through moisture, etc., as a medium, and a poorly water-soluble salt is formed at the point where they meet.

[0126] The ion-releasing compound described above may be an inorganic salt, an ion-exchange resin, or an ion complex.

[0127] Examples of the ion-releasing compounds mentioned above include calcium silicate, tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, barium lactate, calcium sulfate, calcium chloride, calcium nitrate, calcium bicarbonate, sodium hydrogen phosphate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate. It is preferable that the ion-releasing compound is one of these compounds. These ion-releasing compounds can more effectively produce poorly water-soluble salts.

[0128] Examples of compounds capable of releasing the above-mentioned cations include calcium silicate, tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, barium lactate, calcium sulfate, calcium chloride, calcium nitrate, and calcium bicarbonate. Only one of these cation-releasing compounds may be used, or two or more may be used in combination.

[0129] The compound capable of releasing the above cations is preferably calcium silicate, tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, barium lactate, calcium sulfate, calcium chloride, calcium nitrate, or calcium bicarbonate. If the compound capable of releasing the above cations is one of the above preferred compounds, the effects of the present invention can be exhibited more effectively. From the viewpoint of exhibiting the effects of the present invention more effectively, the compound capable of releasing the above cations is more preferably calcium oxide, calcium chloride, calcium nitrate, calcium acetate, calcium lactate, or barium lactate, and even more preferably calcium lactate. From the viewpoint of exhibiting the effects of the present invention more effectively, the compound capable of releasing the above cations is preferably a compound capable of releasing calcium ions, and even more preferably an organic calcium acid salt. Examples of the above organic calcium acid salts include calcium acetate and calcium lactate.

[0130] Examples of compounds capable of releasing the above-mentioned anions include sodium hydrogen phosphate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, and calcium bicarbonate. Only one of these anion-releasing compounds may be used, or two or more may be used in combination.

[0131] From the viewpoint of exhibiting the effects of the present invention more effectively, the compound capable of releasing the above anions is preferably sodium hydrogen phosphate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, or calcium bicarbonate. From the viewpoint of exhibiting the effects of the present invention more effectively, the compound capable of releasing the above anions is more preferably sodium hydrogen phosphate, sodium carbonate, or sodium bicarbonate, and even more preferably sodium bicarbonate. From the viewpoint of exhibiting the effects of the present invention more effectively, the compound capable of releasing the above anions is preferably a compound capable of releasing bicarbonate ions (bicarbonate ions) or carbonate ions.

[0132] Examples of compounds capable of releasing both the cations and anions mentioned above include calcium bicarbonate.

[0133] From the viewpoint of producing poorly water-soluble salts more effectively, the ion-releasing compound is preferably a mixture of a compound capable of releasing cations and a compound capable of releasing anions, and more preferably a mixture of a compound capable of releasing calcium ions and a compound capable of releasing bicarbonate ions or carbonate ions.

[0134] Examples of poorly water-soluble salts include calcium carbonate, barium carbonate, calcium phosphate, calcium sulfate, calcium silicate, and iron hydroxide.

[0135] From the viewpoint of exhibiting the effects of the present invention more effectively, the poorly water-soluble salt is preferably calcium carbonate, barium carbonate, calcium phosphate, or iron hydroxide, and more preferably calcium carbonate. From the viewpoint of exhibiting the effects of the present invention more effectively, the ion-releasing compound is preferably capable of producing calcium carbonate, barium carbonate, calcium phosphate, or iron hydroxide as a poorly water-soluble salt, and more preferably capable of producing calcium carbonate.

[0136] The ion-releasing compound may be in particulate form. The ion-releasing compound may be spherical, or have other shapes, or be flattened. The ion-releasing compound is preferably spherical.

[0137] The particle size of the ion-releasing compound is preferably 1.0 μm or larger, more preferably 5.0 μm or larger, even more preferably 10 μm or larger, preferably 200 μm or smaller, more preferably 150 μm or smaller, and even more preferably 120 μm or smaller. If the particle size of the ion-releasing compound is above the lower limit, the dispersibility in the pressure plate can be improved. Also, if the particle size of the ion-releasing compound is above the lower limit, the ion-releasing compound can be well coated by the coating agent described later, thereby improving the dispersibility in the pressure plate. If the particle size of the ion-releasing compound is below the upper limit, the viscosity when filling the pressure plate material into the installation area (frame) can be improved, and the injectionability of the pressure plate material can be enhanced.

[0138] The particle size of the ion-releasing compound described above is preferably the average particle size. The average particle size described above refers to the number-average particle size. The average particle size of the ion-releasing compound described above can be determined by observing 50 arbitrary ion-releasing compounds with an electron microscope or optical microscope and calculating the average value.

[0139] In the above-mentioned pressure plate, the surface of the ion-releasing compound may be coated with a coating agent. The ion-releasing compound may also be contained within microcapsules. When the ion-releasing compound is an inorganic salt, it is preferable that the surface of the ion-releasing compound in the pressure plate is coated with a coating agent. In particular, when the pressure plate body contains hardened cement milk, hardened mortar, or hardened concrete, it is preferable that the surface of the ion-releasing compound in the pressure plate is coated with a coating agent. Furthermore, when the ion-releasing compound is an inorganic salt, it is preferable that the pressure plate contains microcapsules containing the ion-releasing compound as an encapsulation. When the surface of the ion-releasing compound is coated with a coating agent, or when the ion-releasing compound is contained within microcapsules, the timing and amount of cations or anions released from the ion-releasing compound can be controlled.

[0140] It is preferable that the ion-releasing compound coated with the above coating agent is capable of releasing cations or anions when moisture such as water or humidity comes into contact with the pressure plate and the moisture diffuses into the interior of the coating agent. The ion-releasing compound coated with the above coating agent may also be capable of releasing cations or anions from voids in the coating agent. The ion-releasing compound coated with the above coating agent may also be capable of diffusing into the interior of the coating agent and releasing cations or anions. In these cases, the timing and amount of cations or anions released from the ion-releasing compound can be controlled even more effectively.

[0141] Preferably, the microcapsules described above are capable of releasing the ion-releasing compound. Preferably, the membrane constituting the microcapsules disintegrates when they come into contact with moisture such as water or humidity. In this case, the timing and amount of cations or anions released from the ion-releasing compound can be controlled more effectively.

[0142] The materials for the membrane constituting the microcapsules and the coating agent for covering the surface of the ion-releasing compound can be appropriately selected depending on the type of ion-releasing compound. Preferably, the materials for the membrane constituting the microcapsules and the coating agent for covering the surface of the ion-releasing compound contain a coupling agent or a resin. In this case, the dispersibility of the ion-releasing compound in the pressure plate can be improved, and the timing and amount of cation or anion release can be well controlled. In addition, the thickness of the membrane constituting the microcapsules can be made uniform, and the surface of the ion-releasing compound can be uniformly coated with the coating agent.

[0143] Examples of the coupling agents mentioned above include silane coupling agents and titanium coupling agents.

[0144] Examples of the above-mentioned resins include water-soluble resins, thermoplastic resins, and curable resins. Only one type of resin may be used, or two or more types may be used in combination. If the material of the pressure plate contains a resin, the resin contained in the material of the pressure plate and the resin contained in the material of the coating agent may be the same or different.

[0145] Examples of the water-soluble resins mentioned above include polyvinyl alcohol, polylactic acid resin (PLA resin), poly(meth)acrylic acid, poly(meth)acrylamide, polyvinylpyrrolidone, polyethylene oxide, and methylcellulose.

[0146] Examples of the thermoplastic resins mentioned above include fluororesins, polyolefin resins, polyvinyl chloride resins, polyamide resins, polycarbonate resins, polystyrene resins, polyester resins, acrylonitrile-butadiene-styrene resins (ABS resins), polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA).

[0147] Examples of the polyolefin resins mentioned above include polyethylene, polypropylene, ethylene-propylene copolymer (EPDM), isobutylene-isoprene copolymer, polystyrene, polybutene, polyisobutylene, polybutadiene, acrylonitrile-butadiene copolymer, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer.

[0148] Examples of the curable resins mentioned above include thermosetting resins, photocurable resins, and moisture-curable resins. Only one type of curable resin may be used, or two or more types may be used in combination.

[0149] Examples of the thermosetting resins mentioned above include epoxy resins, phenolic resins, (meth)acrylic resins, unsaturated polyester resins, vinyl ester resins, polyimide resins, urethane resins, and polyurea resins. The thermosetting resins may be used in combination with a thermosetting agent.

[0150] Examples of the above-mentioned photocurable resins include (meth)acrylic resins, (meth)acrylic urethane resins, epoxy resins, and silicone resins. The above-mentioned photocurable resins may be used in combination with a photopolymerization initiator.

[0151] Examples of the above-mentioned moisture-curing resins include moisture-curing urethane resins and hydrolyzable silyl group-containing resins.

[0152] From the viewpoint of further improving the timing and amount of cations or anions released from the ion-releasing compound, the resin contained in the material of the coating agent preferably contains a thermoplastic resin, more preferably a polyolefin resin, and even more preferably an ethylene-vinyl acetate copolymer. From the viewpoint of further improving the timing and amount of cations or anions released from the ion-releasing compound, the resin contained in the material of the coating agent is particularly preferably an ethylene-vinyl acetate copolymer.

[0153] The thickness of the membrane constituting the microcapsule and the thickness of the coating layer made by the coating agent are not particularly limited. From the viewpoint of better controlling the timing and amount of cations or anions released from the ion-releasing compound, the thickness of the membrane constituting the microcapsule and the thickness of the coating layer made by the coating agent are preferably 1 μm or more, more preferably 5 μm or more, preferably 1000 μm or less, and more preferably 200 μm or less.

[0154] The content of the ion-releasing compound in the pressure plate and 100% by weight of the material of the pressure plate is preferably 3% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, particularly preferably 20% by weight or more, preferably 70% by weight or less, more preferably 50% by weight or less, and even more preferably 45% by weight or less. When the content of the ion-releasing compound is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the area where it is installed and its surroundings are densified, and the ground can be reinforced in the long term.

[0155] The content of the ion-releasing compound per 100 parts by weight of the pressure-receiving plate body and the material of the pressure-receiving plate body is preferably 3 parts by weight or more, more preferably 5 parts by weight or more, even more preferably 10 parts by weight or more, particularly preferably 20 parts by weight or more, preferably 200 parts by weight or less, more preferably 100 parts by weight or less, and even more preferably 70 parts by weight or less. When the content of the ion-releasing compound is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the area where it is installed and its surroundings are densified, and the ground can be reinforced in the long term.

[0156] The total content of the ion-releasing compound and the coating agent in 100% by weight of the pressure plate and the material of the pressure plate is preferably 3% by weight or more, more preferably 5% by weight or more, preferably 70% by weight or less, and more preferably 50% by weight or less. When the total content of the ion-releasing compound and the coating agent is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the installed area and its surroundings are densified, and the ground can be reinforced in the long term. When the total content of the ion-releasing compound and the coating agent is below the upper limit, the viscosity when filling the material of the pressure plate into the installation area (within the frame) is improved, and the injectability of the material of the pressure plate can be increased.

[0157] When the pressure plate body contains hardened cement milk, hardened mortar, or hardened concrete, the content of the ion-releasing compound in the material of the pressure plate body relative to the cement content in the cement milk, mortar, or concrete is defined as the content of the ion-releasing compound (A). The content of the ion-releasing compound (A) is preferably 0.2 parts by weight or more, more preferably 0.5 parts by weight or more, preferably 40 parts by weight or less, and more preferably 10 parts by weight or less. When the content of the ion-releasing compound (A) is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the installed area and its surroundings are densified, and the ground can be reinforced in the long term. When the content of the ion-releasing compound (A) is below the upper limit, the viscosity when filling the material of the pressure plate into the installation area (frame) is improved, and the injectability of the material of the pressure plate can be increased.

[0158] <Other ingredients> The pressure plate may, if necessary, contain other components besides the pressure plate body, the ion-releasing compound, and the coating agent. The material of the pressure plate may, if necessary, contain other components besides the material of the pressure plate body, the ion-releasing compound, and the coating agent. Examples of these other components include reaction catalysts, reaction accelerators, crosslinking agents, water absorbers, antioxidants, and colorants.

[0159] (Methods for reinforcing the ground) The ground can be reinforced using the pressure plate according to the present invention. The ground reinforcement method according to the present invention is a ground reinforcement method that reinforces the ground using a ground anchor and the pressure plate described above. The pressure plate may be formed when reinforcing the ground. The pressure plate may be formed when fixing the ground anchor to the ground. In these cases as well, it is understood that a pressure plate is being used in the ground reinforcement method that reinforces the ground.

[0160] The ground reinforcement method according to the present invention has the above configuration, and therefore the ground can be reinforced and maintained in a stable state over a long period of time. The above ground reinforcement method is particularly suitable for reinforcing slopes (embankments).

[0161] The above ground reinforcement method may be carried out by the PUC pressure plate method, the GET pressure plate method, the cushion backfill method, or the set pipe method. The above ground reinforcement method may include, for example, the following steps: (1) drilling holes in the ground; (2) driving in ground anchors; (3) installing set pipes; (4) installing cushion material; (5) arranging pressure plates; (6) injecting cement grout into the cushion material; (7) attaching anchor caps and pressure plate caps.

[0162] The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited to the following examples.

[0163] The following materials were prepared.

[0164] (Pressure plate body) Hardened cement grout or hardened concrete: Cement (Pacific Cement Corporation's "Ordinary Portland Cement") Fine aggregate (Tsukada Ceramics Co., Ltd. "Concrete Powder Sand A No. 7", average particle size 3 mm) Coarse aggregate (Tsukada Ceramics Co., Ltd. "Crushed Stone for Concrete 2005A No. 4", average particle size 25 mm) Mixing water Admixture (Takemoto Oil & Fat Co., Ltd. "Tupole NV-G5")

[0165] Fiber-reinforced plastic: Glass fiber base material (Nitto Boseki Co., Ltd. "Chopped Strand Mat MC600A", basis weight 600g / m²) 2 , width 104cm) Unsaturated polyester resin (Yupika #2120, manufactured by Nippon Yupika Co., Ltd.) PET film (Toray Industries' "Therapeutic" product) Hardening agent (cobalt octylate, cobalt concentration 5 mol%) Catalyst (NOF Corporation's "Permec N")

[0166] Urethane resin body containing long fibers: Glass filaments (glass filaments made by roving together numerous monofilaments with a fiber diameter of 23 μm) Polyether polyol (Sumika Covestro Urethane Co., Ltd. "9158", viscosity 500 mPa·s at 23°C) Diphenylmethane diisocyanate (Tosoh Corporation's "Polymeric MDI", viscosity 200 mPa·s at 23°C) Urethane catalyst 1 (dibutyltin dimalate) Urethane catalyst 2 (tertiary amine compound, "TOYOCAT-DB30" manufactured by Tosoh Corporation) Foaming agent (water) Foam stabilizer (silicone oil, Toray Dow Silicone Co., Ltd. "SZ-1729")

[0167] (Ion-releasing compounds) Sodium bicarbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Sodium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, average particle size 100 μm) Calcium acetate (manufactured by Fujifilm Wako Pure Chemical Industries, average particle size 10 μm) Calcium chloride (manufactured by Fujifilm Wako Pure Chemical Industries, average particle size 107 μm)

[0168] (Coating agent) Ethylene-vinyl acetate copolymer (Tosoh Corporation's "EVA UltraCene #636")

[0169] (Example 1) Fabrication of concrete (material for the main body of the pressure plate): 35 kg of cement, 76.7 kg of fine aggregate, 112.7 kg of coarse aggregate, 15.7 kg of mixing water, and 0.4 kg of admixture were mixed to obtain 240.5 kg of concrete.

[0170] Preparation of test specimen A: Sodium bicarbonate (average particle size 107 μm) and ethylene-vinyl acetate copolymer were melt-mixed in an extruder, extruded into strands, pelletized, then cryopreserved and classified to obtain a powder with an average particle size of 50 μm in which more than a portion of the surface of the sodium bicarbonate was coated with ethylene-vinyl acetate copolymer. The content of ethylene-vinyl acetate copolymer was 80% by weight in 100% by weight of the above powder. 10 kg of the obtained powder was mixed with 100 kg of concrete, filled into a wooden container (width 50 cm × depth 50 cm × height 10 cm), and left to wet-harden for 28 days under conditions of 23°C and 60% RH. After being removed from the container, test specimen A was obtained.

[0171] (Example 2) Fabrication of fiber-reinforced plastic (material for the pressure plate body) and test specimen B: Six PET films were prepared. On each PET film, 1 kg of unsaturated polyester resin, 5 g of curing aid, and 10 g of catalyst were mixed. 250 g of sodium carbonate and 250 g of calcium acetate were added and mixed to prepare an impregnation solution. Six 1 m lengths of glass fiber substrate were also cut. The impregnation solution was sprinkled onto the surface of each glass fiber substrate, the top surface was covered with each PET film, and the glass fibers in the substrate were impregnated using an impregnation roller. After that, each PET film was peeled off, the six films were stacked, and the top and bottom were sandwiched with PET films. After pressing and degassing, the mixture was cured for 2 hours to obtain test specimen B.

[0172] (Example 3) Fabrication of a urethane resin material containing long fibers (material for the pressure plate body): A first composition was obtained by mixing 100 parts by weight of polyether polyol, 0.1 parts by weight of dibutyltin dimalate, 0.3 parts by weight of a tertiary amine compound, 0.12 parts by weight of a foaming agent (water), 0.3 parts by weight of a foam stabilizer, 10 parts by weight of calcium chloride, and 10 parts by weight of sodium bicarbonate (pulverized material obtained by crushing an average particle size of 5 mm and classifying particles smaller than 100 μm). A second composition of 140 parts by weight of diphenylmethane diisocyanate was prepared. Five metal molds with recesses (recess: width 10 cm × depth 50 cm × height 10 cm) and five metal bodies with convex parts (convex part: width 10 cm × depth 50 cm × height 1 cm) were prepared, and long glass fibers were arranged parallel to the depth direction of the recesses in the metal molds.

[0173] Preparation of test specimen C: The second composition was added to the obtained first composition and stirred for 30 seconds to impregnate the glass long fibers of each metal mold. The metal bodies were then arranged so that the convex parts of each metal body faced the concave parts of each metal mold, and left to stand at 23°C for 5 minutes to obtain five urethane foam resin bodies containing long fibers. The five obtained urethane foam resin bodies were bonded in parallel using an adhesive (room temperature curing epoxy resin, ThreeBond Corporation "TB2088E") to obtain test specimen C (width 50 cm × depth 50 cm × height 9 cm).

[0174] (Example 4) Preparation of cement grout (material for the pressure plate body): 20 kg of cement and 10 kg of mixing water were mixed to obtain 30 kg of cement slurry.

[0175] Preparation of test specimen D: Sodium carbonate and ethylene-vinyl acetate copolymer were melt-mixed in an extruder, extruded into strands, pelletized, then cryopreserved and classified to obtain a powder with an average particle size of 50 μm in which more than a portion of the surface of the sodium carbonate was coated with ethylene-vinyl acetate copolymer. Similarly, calcium acetate and ethylene-vinyl acetate copolymer were melt-mixed in an extruder, extruded into strands, pelletized, then cryopreserved and classified to obtain a powder with an average particle size of 50 μm in which more than a portion of the surface of the calcium acetate was coated with ethylene-vinyl acetate copolymer. The content of ethylene-vinyl acetate copolymer was 50% by weight in 100% by weight of each of the above powders. 5 kg each of the obtained powders was mixed with 100 kg of cement milk to obtain material D for the pressure plate.

[0176] Glass beads were filled into a cylindrical container (10 cm in diameter x 50 cm in height), and a stainless steel mesh cylinder (2 cm in diameter x 50 cm in height, wire diameter 0.052 mm, mesh size 200 mesh) was inserted into the center of the container. The glass beads inside the stainless steel mesh cylinder were removed to form a simulated injection hole. The obtained pressure plate material D was injected into the simulated injection hole and allowed to harden for 28 days at 23°C and 60% RH to obtain test specimen D.

[0177] (Comparative Example 1) Test specimen E was obtained in the same manner as in Example 1, except that an ion-releasing compound and a coating agent were not used.

[0178] (Comparative Example 2) Test specimen F was obtained in the same manner as in Example 2, except that an ion-releasing compound was not used.

[0179] (Comparative Example 3) Test specimen G was obtained in the same manner as in Example 3, except that an ion-releasing compound was not used.

[0180] (Comparative Example 4) Test specimen H was obtained in the same manner as in Example 4, except that an ion-releasing compound and a coating agent were not used.

[0181] (evaluation) (1) Formation of poorly water-soluble salts The specimens obtained in Examples 1-3 and Comparative Examples 1-3 were placed on the surface of moistened silica sand and left to stand for one month. After that, the underside of each specimen and the surface of the silica sand surrounding each specimen were visually inspected in detail to see if particles had precipitated.

[0182] Furthermore, water was poured into the containers of Example 4 and Comparative Example 4 to a height of 30 cm and left to stand for one month. After that, the surface of each cylinder and the surface of the glass beads surrounding each cylinder were visually observed in detail to see whether or not particles had precipitated.

[0183] In Examples 1-3, particles precipitated on both the surface of the test specimen and the surface of the surrounding silica sand. In Example 4, particles precipitated on both the surface of the cylinder and the surface of the glass beads surrounding the cylinder. On the other hand, in Comparative Examples 1-3, no particles precipitated on either the surface of the test specimen or the surface of the surrounding silica sand. In Comparative Example 4, no particles precipitated on either the surface of the cylinder or the surface of the glass beads surrounding the cylinder. In the test specimens where particles precipitated on the surface, observation using a scanning electron microscope revealed aggregates of particles with a dense crystalline structure (calcite structure of calcium carbonate).

[0184] In other words, the formation of poorly water-soluble salts was confirmed in Examples 1 to 4, while the formation of poorly water-soluble salts was not confirmed in Comparative Examples 1 to 4.

Claims

1. It comprises a pressure-receiving plate body and an ion-releasing compound capable of releasing cations or anions, The ion-releasing compound is capable of producing poorly water-soluble salts. A pressure plate wherein the ion-releasing compound includes potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, calcium bicarbonate, calcium acetate, or calcium chloride.

2. The pressure plate according to claim 1, wherein the poorly water-soluble salt is calcium carbonate.

3. The ion-releasing compound includes a compound capable of releasing cations, The pressure plate according to claim 1 or 2, wherein the compound capable of releasing the cation is calcium acetate or calcium chloride.

4. The ion-releasing compound includes a compound capable of releasing anions, The pressure plate according to claim 1 or 2, wherein the compound capable of releasing the anion is potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, or calcium bicarbonate.

5. The pressure plate according to claim 1 or 2, wherein the surface of the ion-releasing compound is coated with a coating agent.

6. The pressure receiving plate according to claim 1 or 2, wherein the pressure receiving plate body includes a urethane resin body containing long fibers, fiber-reinforced plastic, a hardened cement milk product, a hardened mortar product, or a hardened concrete product.

7. A method for reinforcing the ground, comprising using a ground anchor and a pressure-receiving plate according to claim 1 or 2, and generating a poorly water-soluble salt by releasing cations or anions from the ion-releasing compound contained in the pressure-receiving plate.

8. The method for reinforcing the ground according to claim 7, wherein the pressure-receiving plate body includes a hardened cement milk or a hardened mortar.

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