JP4794881B2 - Filler and filling method - Google Patents

Description

  The present invention relates to a filling material and a filling method for filling a cavity generated around a tunnel or a sewer pipe and preventing a structure from being destroyed by an earthquake or a natural pressure.

Around underground structures such as tunnels and sewer pipes, cavities are created by the movement of groundwater. Cavities cause stress concentration due to earthquakes and natural ground pressure, and structures are easily destroyed. Therefore, it is effective to inject a backing material into surrounding cavities such as tunnels and sewer pipes.
Conventionally, cement-based materials and water glass-based materials have been mainly used, and the back surfaces of tunnels and sewer pipes are filled with concrete pumps or the like (see Patent Document 1). Moreover, in order to prevent the material filled by the movement of groundwater from being washed away during the construction, development of a material imparted with quick setting has been promoted (see Patent Document 2).
On the other hand, it has been studied to inject a polymer material into the ground (see Patent Documents 3 and 4).
JP 11-61123 A Japanese Patent No. 3600155 JP 2002-294014 JP JP 2002-371278 A

  However, when the cavities around the underground structure are filled with conventional materials, there are problems such as generation of voids and moisture by the groundwater. Therefore, a specific filler and a filling method for solving these problems and improving the durability of the structure are provided.

The present invention provides: (1) polyvinyl alcohol, cross-linking agents, catalysts, and foaming agent, or foam product made from the added aqueous solution and air foaming agent Ri name contains an average polymerization degree of the polyvinyl alcohol 500 to 3000, an aqueous solution having a saponification degree of 80 mol% or more and a solid content concentration of 5 to 25% by mass, and the crosslinking agent is selected from the group consisting of aldehydes and compounds having a methylol group and / or an amino group and at least one, the weight ratio of the solid content of the polyvinyl alcohol and the crosslinking agent is 1: 0.25 to 5, filler density after curing is 0.3 to 1 g / cm ^3, (2) (1) It is a filling method for a structure that fills a cavity formed around the underground structure, and a filling method that injects the fillers of ( 3 ) and (1 ) into the soil around the underground structure.

  According to the present invention, the filler can be filled into a cavity or soil around an underground structure such as a tunnel and a sewer pipe, and an appropriate water shielding property can be secured, so that the durability of the structure can be improved.

The polyvinyl alcohol used in the present invention is not particularly limited as long as it exhibits water solubility. In particular, those having an average degree of polymerization of 500 to 3000 and a degree of saponification of 80 mol% or more are preferred from the viewpoints of fluidity before curing, strength and elasticity after curing, and water shielding properties. Further, a modified or copolymerized type in which acrylic acid, crotonic acid, maleic acid, acrylamide or the like is added to polyvinyl alcohol may be used as long as the effects of the present invention are not impaired.
The polyvinyl alcohol used in the present invention is used as an aqueous solution and its solid content concentration is appropriately determined depending on the shape of the construction site and the like, and is not particularly limited, but is usually about 5 to 25% by mass. It is preferable that If it is less than 5% by mass, the strength, elasticity and water resistance after curing may be insufficient, and if it exceeds 25% by mass, the viscosity of the aqueous solution may be high and affect the filling.

The cross-linking agent used in the present invention is not particularly limited as long as it is a substance that reacts with a hydroxyl group (—OH) or a carboxyl group (—COOH). Usually, a cross-linking agent used as a cross-linking agent for polyvinyl alcohol is used. Can be used.
Examples of the substance that reacts with a hydroxyl group or a carboxyl group include glyoxal, formaldehyde, propyl aldehyde, n-butyraldehyde, tert-butyraldehyde, amyl aldehyde, hexyl aldehyde, aliphatic aldehydes such as 2-ethylhexyl aldehyde, and fats such as cyclohexyl aldehyde. Aromatic aldehydes such as cyclic aldehydes, benzaldehyde, alkyl-substituted benzaldehydes, halogen-substituted benzaldehydes, phenyl-substituted alkyl aldehydes, compounds having a methylol group such as trimethylol melamine, hexamethylol melamine, dimethylol urea, dimethylol ethylene urea, poly Compounds having amino groups such as acrylic amine, polyamide polyamine, urea, polyethyleneimine, epoxy resin system Compound, boron compound such as boric acid, Ti, Zr, metal alkoxides such as is bonded to organic material Al, include compounds having an isocyanate group. Above all, from the viewpoints of securing filling work time, strength after curing, elasticity, water resistance, and material safety, it is selected from compounds having aldehydes and methylol groups and / or amino groups, or compounds having isocyanate groups. It is preferable to use those prepared, and it is possible to synthesize better crosslinked products by using two or more of the above substances in combination.
The addition rate of the crosslinking agent is determined by the mass ratio of the solid content of polyvinyl alcohol and the solid content of the crosslinking agent, and the mass ratio is preferably added in the range of 1: 0.25 to 5. If the mass ratio of the hydroxyl group to the reactive group is less than 0.25, the strength of the cured product is low, and even if it exceeds 5, the elasticity is not improved.

  The catalyst used in the present invention is not particularly limited as long as it promotes the reaction between polyvinyl alcohol and the crosslinking agent, and it is common to use an acidic substance or a basic substance, and it is preferable to change the type depending on the type of reaction. For example, when an aldehyde, a compound having a methylol group and / or amino group, or an isocyanate group is used as a crosslinking agent, an inorganic acid such as sulfuric acid or hydrochloric acid, citric acid, acetic acid, gluconic acid, oxalic acid, formic acid, lactic acid, etc. It is preferable to use the organic acid.

  The foaming agent used in the present invention is used for the purpose of reducing the weight of the filler, adjusting the water shielding and water permeability, and efficiently filling the unit space. Surfactants such as alkyl ethers and fatty acid carboxylates and sulfates, amines such as alkanolamines and ethanolamines, peroxides such as sodium perborate and sodium percarbonate can be used. Specific examples of products include “Emar D-3-D” manufactured by Kao Corporation, “Cellfoam L” manufactured by Cellfoam Technology Laboratory Co., Ltd., “Liporan 2800L” manufactured by Lion Corporation, “Denka SR” manufactured by Denki Kagaku Kogyo Co., Ltd. -F ".

The method for introducing bubbles in the filler of the present invention is not particularly limited. From the viewpoint of introducing bubbles uniformly into the filler, the foam is first prepared, and the aqueous polyvinyl alcohol solution, the crosslinking agent, and the catalyst are prepared. A method of mixing with a gel-forming substance comprising: Although a foam is not specifically limited, For example, it can make from the aqueous solution and air which added the foaming agent. An example of the foaming device is one that sends compressed air to a cylindrical container containing beads having a size of 1 to 2 mm. When the foam-containing aqueous solution is quantitatively fed into the cylindrical container with a plunger-type pump, bubbles are obtained. A mixing method of the foam and the aqueous polyvinyl alcohol solution, the crosslinking agent, and the catalyst is not particularly limited, and various mixers can be used. Further, a foaming agent may be added to a gel-forming substance composed of an aqueous polyvinyl alcohol solution, a crosslinking agent, and a catalyst to generate bubbles during mixing.
The addition rate of the foaming agent varies depending on the concentration of the aqueous polyvinyl alcohol solution and the type of the crosslinking agent and the catalyst, and thus cannot be specifically limited. However, in the case of a surfactant component, about 0.01 to 2% by mass is added to the aqueous solution. It is preferable. If the amount is less than 0.01% by mass, predetermined bubbles may not be introduced.If the amount exceeds 2% by mass, the amount of bubbles is too much and the flowability of the polyvinyl alcohol aqueous solution decreases, or the strength, elasticity, and water resistance after curing. May decrease. It is also possible to control the amount of bubbles by using an antifoaming agent in combination.

The filler density after curing is preferably 0.3 to 1 g / cm ³ . If it is less than 0.3 g / cm ³ , the strength, elasticity, and water resistance of the cured product may be insufficient, and if it exceeds 1 g / cm ³ , the water shielding property is too high to be in harmony with the surrounding environment and voids around the filling area. May occur or the weight of the filler itself may affect.

  When the filler of the present invention is injected into the soil, the relative permeability coefficient of the injected soil is preferably about 20 to 100%. The relative hydraulic conductivity is the ratio of the hydraulic conductivity of the injected soil when the hydraulic conductivity of the soil alone is taken as 100. The measurement of the hydraulic conductivity is based on JIS A 1218. If the relative hydraulic conductivity is less than 20%, the water impermeability is high, so that a cavity may be formed again between the soil interface after the injection and the soil, and if it exceeds 100%, the strength, elasticity and water resistance of the injected soil will be reduced There is a case.

  In the filler of the present invention, a filler can be used for the purpose of controlling the strength and elastic modulus, water permeability, water shielding, and density of the cured product. The filler is not particularly limited, and an inorganic or organic filler can be used. Examples of inorganic materials include aggregates such as silica and limestone, clay minerals such as bentonite, ion exchangers such as zeolite, and organic materials include fibrous substances such as vinylon fiber, acrylic fiber, and carbon fiber, Examples thereof include ion exchange resins and water-absorbing polymers. These can be used as long as the object of the present invention is not impaired.

  As the mixing device for the filler in the present invention, any existing device can be used, and examples thereof include a tilting barrel mixer, an omni mixer, a Henschel mixer, a V-type mixer, and a nauter mixer.

  Examples will be described in detail below.

"Example 1"
A polyvinyl alcohol aqueous solution having a solid content concentration of 10% by mass was prepared using polyvinyl alcohol (PVA) having a polymerization degree of 1700 and a saponification degree of 99 mol% and tap water. As the crosslinking agent for 1000 g of this polyvinyl alcohol aqueous solution, the types and amounts of aldehydes shown in Table 1 were added to change the mass ratio of the solid content of the polyvinyl alcohol and the solid content of the crosslinking agent. Thereafter, acetic acid was added as a catalyst to adjust the pH to 4 to prepare a gel-forming substance. On the other hand, a 1% by mass aqueous solution of a foaming agent was prepared and sent to a foaming apparatus at a rate of 0.15 L / min. At the same time, bubbles were prepared with compressed air at a rate of 4 L / min. Finally, the gel-forming substance and the foam were mixed to produce the filler of the present invention. This filler was filled in a 100 × 100 × 100 mm mold and cured for 7 days in an environment of 20 ° C. and a humidity of 80% RH. Thereafter, the mold was removed from the mold, and the density, water resistance, and elasticity of the cured product were evaluated. The results are shown in Table 1.

"Materials used"
Polyvinyl alcohol: Denki Kagaku Kogyo K17 degree of polymerization 1700 degree of saponification 99.0 mol%
Cross-linking agent: terephthalaldehyde, commercially available foaming agent: “DENKA SRF” manufactured by Denki Kagaku Kogyo Co., Ltd., alkyl ether sulfate salt-based acetic acid: commercially available product, reagent grade 1

"Measuring method"
Density: Calculated from the mass and volume of the cured product.
Water resistance: 5 L of water was put into a plastic container and adjusted to 35 ° C. The 100 × 100 × 100 mm cured body produced in this container was immersed and allowed to stand for 1 month to evaluate the water resistance of the cured body. The water in the container was changed every week.
Elasticity: Judged by the touch of the cured body cured for 7 days.

<Water resistance evaluation criteria>
A: Insoluble in water and almost no volume change.
○: Insoluble in water, volume change of the cured product.
Δ: Partially dissolved in water and volume change.
X: Dissolved in water.

<Elasticity evaluation criteria>
A: Elasticity and stickiness.
○: Although there is elasticity, there is little stickiness.
Δ: Less elastic and less sticky.
X: There is no elasticity.

  As shown in Table 1, it can be seen that the filler of the present invention using aldehydes as a crosslinking agent has a small density and a light weight, and is excellent in water resistance and elasticity.

"Example 2"
The same procedure as in Example 1 was conducted except that the cross-linking agent was a methylol group-containing compound and the type and amount thereof were changed as shown in Table 2. The results are shown in Table 2.

"Materials used"
Cross-linking agent: Trimethylol melamine, commercial product, containing methylol group

  As shown in Table 2, it can be seen that the filler of the present invention using a compound having a methylol group as a crosslinking agent is light in density and lightweight, and excellent in water resistance and elasticity.

"Example 3"
The same procedure as in Example 1 was performed except that polyvinyl alcohol was an acrylamide-modified product, the crosslinking agent was an amino group-containing compound, the amount of the crosslinking agent was changed as shown in Table 3, and the pH was not adjusted. The results are shown in Table 3.

"Materials used"
Polyvinyl alcohol: “PC100” manufactured by Denki Kagaku Kogyo Co., Ltd. Degree of polymerization: 1700 Saponification degree: 88.0 mol%, Acrylamide-modified cross-linking agent: Polyethyleneimine, commercial product, amino group

  As shown in Table 3, it can be seen that the filler of the present invention using an amino group-containing compound as a crosslinking agent is small in density and light in weight and excellent in water resistance and elasticity.

Example 4
The same procedure as in Example 1 was conducted except that the concentration, polymerization degree, and saponification degree of the polyvinyl alcohol used were changed as shown in Table 4. However, the trimethylol melamine of Example 2 was used as the cross-linking agent, and the addition amount with respect to 1000 g of the polyvinyl alcohol aqueous solution was adjusted so that the mass ratio of the polyvinyl alcohol solid content and the cross-linking agent solid content was 1: 2. The results are shown in Table 4.

  As shown in Table 4, when the concentration of polyvinyl alcohol is 5 to 25% by mass, the degree of polymerization is 500 to 3000, and the degree of saponification is 80 mol% or more, the filler is small and light in weight, and has excellent water resistance and elasticity. It can be seen that

"Example 5"
Acetic acid was added to 1000 g of an aqueous polyvinyl alcohol solution having a solid content concentration of 10% by mass to adjust the pH to 4, and a foaming agent was added to this aqueous solution to a concentration of 1% by mass. This aqueous solution was stirred and mixed at high speed to introduce bubbles, and then 50 g of a trimethylolmelamine aqueous solution (solid content: 80% by mass) was added as a crosslinking agent and further mixed to prepare a filler. The physical properties of the filler were evaluated in the same manner as in Example 1. The results are shown in Table 5.

"Materials used"
Polyvinyl alcohol: Denki Kagaku Kogyo K17 degree of polymerization 1700 degree of saponification 99.0 mol%
Acetic acid: commercial product, reagent primary foaming agent: “Denka SRF” manufactured by Denki Kagaku Kogyo Co., Ltd., alkyl ether sulfate salt-based crosslinking agent: trimethylol melamine, commercial product, containing methylol group

  As shown in Table 5, it can be seen that by mixing the foaming agent and stirring at high speed, a filler having a small density and light weight and excellent in water resistance and elasticity can be obtained.

"Example 6"
Using the same material as in Example 5, a polyvinyl alcohol aqueous solution having a solid content concentration of 10% by mass was prepared. To 1000 g of this polyvinyl alcohol aqueous solution, 200 g of trimethylol melamine as a crosslinking agent (solid content mass ratio = 1: 2), Acetic acid was added as a catalyst to adjust the pH to 4. Thereafter, foam was prepared in the same manner as in Example 1, and the filler having the density shown in Table 6 was produced by changing the mixing ratio of the foam and the aqueous solution.
On the other hand, the structure as shown in FIG. 1 was constructed by simulating a sewer pipe buried underground using a plastic mold, a fume pipe, and sand sand. A large number of holes with a diameter of 20 mm were provided in the fume pipe, and the holes were temporarily closed, and a cavity of about 20 mm was provided between the fume pipe and pure sand. Thereafter, only one hole was opened and the filler of the present invention was injected therefrom. In addition, let the case where it fills with a pure sand soil without inject | pouring a filler into a cavity be a comparative example.
After 7 days from filling, water was sprayed from the upper part of the structure shown in FIG. The amount of water is expressed as a ratio to the amount of water sprayed (water elution rate). The results are shown in Table 6.

  As shown in Table 6, it can be seen that by using the filler of the present invention, no cavities are generated even in a flowing water environment, and entry of groundwater into the inside of the fume pipe can be suppressed.

  According to the present invention, a filler can be filled in a cavity or soil around an underground structure such as a tunnel and a sewer pipe to ensure appropriate water shielding and improve the durability of the structure. Widely applicable.

Schematic diagram showing the relationship between a fume pipe, a pure sand soil, and a cavity for explaining an example of the filling method of the present invention ((a) a sectional view in the radial direction of the fume pipe, (b) a sectional view in the longitudinal direction of the fume pipe) It is.

Explanation of symbols

1: Hume tube 2: Hume tube hole 3: Cavity 4: Pure sand

Claims (3)

Polyvinyl alcohol, cross-linking agents, catalysts, and foaming agent, or foam product made from the added aqueous solution and air foaming agent Ri name contains an average polymerization degree of the polyvinyl alcohol is 500 to 3000 and a saponification degree of 80 mol% The solid content concentration is an aqueous solution having a solid content of 5 to 25% by mass, and the crosslinking agent is at least one selected from the group consisting of aldehydes and a compound having a methylol group and / or an amino group, and polyvinyl alcohol. the mass ratio of the solid content of the crosslinking agent is 1: 0.25 to 5, filler density after curing is 0.3 to 1 g / cm ^3. A filling method according to claim 1, wherein the filling material according to claim 1 is filled in a cavity formed around an underground structure. A filling method according to claim 1, wherein the filler according to claim 1 is poured into the soil around the underground structure.