Chemicals for shield tunneling and shield tunneling

Abstract

This invention provides a chemical agent for shield tunneling that has a low viscosity in its undiluted form and allows for a higher viscosity in its diluted solution. [Solution] A shield tunneling agent comprising a water-soluble vinyl polymer emulsion (A), wherein the conductivity of a 1% by mass aqueous solution of the shield tunneling agent is 500 μS / cm or more.

Description

[Technical Field]

[0001] This invention relates to chemicals for shield tunneling and shield tunneling methods. [Background technology]

[0002] In the mud-filled shield tunneling method, water-soluble polymer agents are mainly used for the purpose of stabilizing the tunnel face, controlling the flow of excavated soil, and preventing soil adhesion to the equipment (for example, Patent Document 1). Water-soluble polymer agents are diluted with water at the excavation site, supplied to the front of the excavation face, inside the chamber, inside the screw conveyor, etc., and used after being mixed with soil and sand. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 8-19401 [Overview of the project] [Problems that the invention aims to solve]

[0004] For shield tunneling methods, water-soluble polymer chemicals need to have low viscosity in their undiluted form for ease of handling. On the other hand, for performance aspects such as controlling the flowability of excavated soil and preventing soil adhesion to equipment, high viscosity is required at the concentration used after dilution. In other words, in shield tunneling, the chemicals supplied to the soil have low viscosity in their undiluted form, and it is desirable that they have high viscosity at the concentration used. However, achieving such viscosity behavior has been difficult. This invention has been made in view of the above circumstances, and aims to provide a chemical agent for shield tunneling that has a low viscosity in the undiluted solution and a higher viscosity in the diluted solution. [Means for solving the problem]

[0005] The present invention has the following aspects. [1] A chemical for shield construction methods comprising a water-soluble vinyl polymer emulsion (A), wherein the 1% by mass aqueous solution of the chemical for shield construction methods has an electrical conductivity of 500 μS / cm or more. [2] The chemical for shield construction methods according to [1], further comprising an additive (B) that is one or more selected from the group consisting of a compound (B1) represented by the following general formula (b1) and a compound (B2) represented by the following general formula (b2).

[0006]

Chemical Formula

[0007] (wherein, R 3 represents an alkyl group or alkenyl group having 8 to 20 carbon atoms, each AO independently represents an alkylene oxide unit having 2 to 4 carbon atoms, q, r, s, and t represent the average number of added moles of AO, and the sum of q, r, s, and t is a number from 15 to 25.)

[0008]

Chemical Formula

[0009] (wherein, R 4 each independently represents a hydroxy group or a hydroxyalkyl group having 1 to 3 carbon atoms, and R 5 represents an alkyl group having 6 to 20 carbon atoms.) [3] The chemical for shield construction methods according to [1] or [2], wherein the viscosity of the chemical for shield construction methods at 20°C is 800 mPa·s or less, and the viscosity of a 1% by mass aqueous solution of the chemical for shield construction methods at 20°C is 200 mPa·s or more. [4] A shield construction method, comprising a step of supplying a treatment liquid containing the chemical for shield construction methods according to any one of [1] to [3] so as to mix with excavated earth and sand. [5] A shield construction method, comprising a step of supplying the chemical for shield construction methods according to any one of [1] to [3] and bubbles obtained by foaming a diluted solution of a foaming agent so as to mix with excavated earth and sand. [6] The shield tunneling method according to [5], wherein the foaming agent comprises the following components (D) and (E). (D) Ingredient: Anionic surfactant. (E) Components: Alcohols having an aliphatic hydrocarbon group with 8 to 20 carbon atoms. [Effects of the Invention]

[0010] According to the present invention, a shield tunneling agent is obtained in which the viscosity of the undiluted solution is low and the viscosity of the diluted solution is higher, as well as a shield tunneling method using the same. [Modes for carrying out the invention]

[0011] The following definitions of terms apply throughout this specification and the claims. A "water-soluble polymer" refers to a polymer whose solubility in water (at 20°C) is 0.1g / 100g of water or more. "Polymer" refers to a polymer with a weight-average molecular weight of 500 or more. In polymer terminology, a "unit" refers to a unit (atomic group) formed from a single monomer molecule. The weight-average molecular weight of water-soluble vinyl polymers is measured by gel permeation chromatography using polyethylene glycol as the standard substance. "(Meth)acrylic" is a general term for "acrylic" and "methacrylic". A numerical range represented by "~" means a range of numbers whose lower and upper limits are the numbers before and after the "~".

[0012] The conductivity value of a 1% by mass aqueous solution of the shield tunneling agent is obtained by diluting the solution with deionized water to a concentration of 1% by mass, adjusting the temperature of the solution to 20°C, and then measuring it with a conductivity meter (for example, Custom Corporation contact-type conductivity meter, product name "Waterproof Conductivity Meter CD-6021").

[0013] The viscosity value of the shield tunneling agent is obtained by first adjusting the temperature of the shield tunneling agent to 20°C, then measuring it using a Type B viscometer under the conditions of a rotation speed of 60 rpm and a measurement time of 60 seconds. The viscosity of a 1% by mass aqueous solution of the shield tunneling agent is obtained by diluting the solution with ion-exchanged water to a concentration of 1% by mass, adjusting the temperature of the solution to 20°C, and then measuring it using a Type B viscometer under the conditions of a rotation speed of 60 rpm and a measurement time of 60 seconds.

[0014] Chemicals for shield tunneling The chemical agent for the shield tunneling method in this embodiment (hereinafter also referred to as "chemical stock") is a composition containing a water-soluble vinyl polymer emulsion (A) (hereinafter also referred to as emulsion (A)), and the conductivity of a 1% aqueous solution (hereinafter also referred to as "1% aqueous solution") obtained by diluting the chemical stock with water to a content of 1% by mass is 500 μS / cm or more. The drug stock solution may be a composition consisting of a water-soluble vinyl polymer emulsion (A), and may further contain an additive (B).

[0015] <Water-soluble vinyl polymer emulsion (A)> Emulsion (A) is a white emulsion containing a water-soluble vinyl polymer (A1), an oil (A2), and water (A3). It may also contain other components (A4) other than (A1) to (A3). Emulsion (A) may be a water-in-oil (W / O) emulsion, an oil-in-water (O / W) emulsion, or an emulsion obtained by adding water to a W / O emulsion and mixing them.

[0016] The water-soluble vinyl polymer (A1) is preferably a homopolymer or copolymer of monomers having vinyl groups, and more preferably a copolymer. The water-soluble vinyl polymer (A1) preferably has ionic groups that dissociate in water to generate ions (anions or cations). It is preferable that at least a portion of the units constituting the water-soluble vinyl polymer (A1) have ionic groups. The water-soluble vinyl polymer (A1) is preferably a copolymer of one or more nonionic monomers that do not have ionic groups and one or more ionic monomers that have ionic groups. Examples of nonionic monomers include (meth)acrylamide, styrene, and vinyl acetate. Acrylamide is preferred. Examples of ionic monomers include (meth)acrylic acid, (meth)acrylic acid salts, vinyl sulfonic acid, and vinyl sulfonate salts. Of these, acrylic acid and acrylic acid salts are preferred. Sodium acrylate is preferred as the acrylic acid salt. The weight-average molecular weight of the water-soluble vinyl polymer (A1) is preferably 1 million to 20 million, more preferably 3 million to 10 million, and even more preferably 3 million to 8 million.

[0017] Examples of oils (A2) include hydrocarbon solvents, vegetable oils, and higher alcohols. Hydrocarbon solvents are preferred. Examples of hydrocarbon solvents include mineral oil, liquid paraffin, and turbine oil. Mineral oil is preferred.

[0018] The water (A3) contained in emulsion (A) may be the water used in the production of the water-soluble vinyl polymer (A1), or it may be the water added in the production of the water-soluble vinyl polymer (A1), or both.

[0019] Other components (A4) may include surfactants, preservatives, stabilizers, etc. Other components (A4) may also include components used in the synthesis of the water-soluble vinyl polymer (A1). Nonionic surfactants are preferred as surfactants. Examples of nonionic surfactants include compounds represented by the following general formula (a1). R 1 -(AO)pR 2 ...(a1) In general formula (a1), R 1 R represents a straight-chain or branched hydrocarbon group with 10 to 30 carbon atoms. 2represents either a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 20 carbon atoms. AO represents a linear or branched alkylene oxide unit having 2 to 4 carbon atoms, p represents the average number of added moles of AO, and is a number of 0 to 30. R 1 has 10 to 30 carbon atoms, preferably 10 to 25, more preferably 12 to 22, and still more preferably 12 to 20. R 2 the hydrocarbon group has 1 to 20 carbon atoms, preferably 1 to 18, more preferably 1 to 16, and still more preferably 1 to 14. p is a number of 0 to 30, preferably 0 to 25, more preferably 0 to 20, and still more preferably 0 to 16. When emulsion (A) contains a nonionic surfactant (a1) represented by formula (a1), the viscosity of a diluted drug stock solution is more easily increased.

[0020] Emulsion (A) can be produced by a method including mixing an oil agent (A2) and a surfactant in a reaction vessel, adding an aqueous monomer solution and a polymerization initiator while stirring, and carrying out a polymerization reaction to synthesize a water-soluble vinyl polymer (A1). After the polymerization reaction, a surfactant may be added as necessary.

[0021] Based on the total mass of emulsion (A), the content of water-soluble vinyl polymer (A1) is preferably 20 to 60% by mass, more preferably 25 to 50% by mass, and still more preferably 28 to 40% by mass. When the content of the water-soluble vinyl polymer (A1) is not less than the lower limit of the above range, performances such as fluidity control of excavated earth and sand and prevention of earth adhesion to equipment are good, and when the content is not more than the upper limit, the viscosity of the stock solution can be kept low and handling properties are good. Based on the total mass of emulsion (A), the content of the oil agent (A2) is preferably 30 to 50% by mass, more preferably 35 to 49% by mass, and still more preferably 35 to 47% by mass. When the content of the oil agent (A2) is within the above range, an emulsion with good stability can be obtained. The water (A3) content is preferably 5 to 40% by mass, more preferably 7 to 35% by mass, and even more preferably 10 to 32% by mass, relative to the total mass of emulsion (A). An emulsion with good stability can be obtained when the water (A3) content is within the above range. When emulsion (A) contains a nonionic surfactant (a1) represented by formula (a1) as another component (A4), the content of the nonionic surfactant (a1) relative to the total mass of emulsion (A) is preferably 1 to 10% by mass, more preferably 1 to 8% by mass, and even more preferably 1 to 5% by mass. An emulsion with good stability can be obtained when the content of the nonionic surfactant (a1) is within the above range. The total content of other components (A4) other than the nonionic surfactant (a1) relative to the total mass of emulsion (A) is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less. It may be zero.

[0022] When the water-soluble vinyl polymer (A1) is a copolymer of an ionic monomer and a nonionic monomer, the molar ratio of nonionic monomer to ionic monomer, expressed as nonionic monomer / ionic monomer, is preferably 50 / 50 to 90 / 10, more preferably 55 / 45 to 80 / 20, and even more preferably 60 / 40 to 70 / 30. When the molar ratio of nonionic monomer to ionic monomer is above the lower limit of the above range, excessive aggregation is less likely to occur when mixed with soil, and when it is below the upper limit, appropriate cohesive force and anti-adhesion effect are further enhanced when mixed with soil.

[0023] <Additive (B)> Additive (B) is one or more compounds selected from the group consisting of compounds (B1) represented by the following general formula (b1) and compounds (B2) represented by the following general formula (b2). Additive (B) contributes to increasing the viscosity of the diluted solution of the drug concentrate.

[0024] [ka]

[0025] [ka]

[0026] [Compound (B1)] Compound (B1) is a sorbitan-based nonionic surfactant. In equation (b1), R 3 R is an alkyl or alkenyl group having 8 to 20 carbon atoms. The alkyl group may be linear or branched, but linear is preferred. The alkenyl group may be linear or branched, but linear is preferred. 3 The number of carbon atoms is preferably 4 to 30, more preferably 8 to 20, and even more preferably 11 to 17. In formula (b1), AO is an alkylene oxide unit having 2 to 4 carbon atoms. The carbon chain of the alkylene oxide may be straight or branched. Multiple AOs present in a single molecule may be the same or different from one another. In formula (b1), q, r, s, and t represent the average number of moles of AO added. The sum of q, r, s, and t is a number between 15 and 25, preferably between 16 and 24, more preferably between 17 and 23, and even more preferably between 18 and 22.

[0027] Examples of compound (B1) include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monopalmitate. Compound (B1) may be used alone, or two or more may be used in combination. Compound (B1) can also be obtained from commercially available products.

[0028] [Compound (B2)] Compound (B2) is an alkyl glycoside nonionic surfactant. In equation (b2), R 4 R is a hydroxyl group or a hydroxyalkyl group having 1 to 3 carbon atoms. The carbon chain of the hydroxyalkyl group having 3 carbon atoms may be straight or branched, but a straight chain is preferred. Multiple Rs are present in one molecule. 4They may be the same or different from each other. 4 The hydroxyalkyl group preferably has 1 to 2 carbon atoms, and more preferably 1 carbon atom. In equation (b2), R 5 R is an alkyl group having 6 to 20 carbon atoms. The alkyl group may be linear or branched, but linear is preferred. 5 The number of carbon atoms is preferably 6 to 19, more preferably 7 to 18, and even more preferably 8 to 16.

[0029] An example of compound (B2) is one R 4 The hydroxymethyl group is the remaining R 4 The group is a hydroxyl group, and R 5 A compound in which is a linear alkyl group with 8 carbon atoms, one R 4 The hydroxymethyl group is the remaining R 4 The group is a hydroxyl group, and R 5 Examples include compounds in which the alkyl group is a linear alkyl group with 16 carbon atoms. A preferred example of compound (B2) is GOR 5 (G represents the residue obtained by removing the hydroxyl group at position 1 from glucose.) Compound (B2) may be used alone, or two or more may be used in combination. Compound (B2) can also be obtained from commercially available products.

[0030] When the chemical agent for shield tunneling (concentrated chemical solution) contains additive (B), the content of additive (B) relative to the total mass of the concentrated chemical solution is preferably 0.5 to 4% by mass, more preferably 1 to 3% by mass, and even more preferably 1 to 2% by mass. If the content of additive (B) is above the lower limit of the above range, the viscosity during dilution improves, and if it is below the upper limit, the viscosity of the concentrate is kept low, resulting in good handling.

[0031] <Optional component (C)> The chemical agent for shield tunneling (undiluted chemical solution) may contain optional components (C) other than the emulsion (A) and additives (B). As optional component (C), any component known in shield tunneling chemicals can be used, as long as it does not impair the effects of the present invention. Examples include thickeners, flocculants, and immobilizers. The total content of optional component (C) relative to the total mass of the drug stock solution is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. It may be zero. When the content of optional component (C) is below the above upper limit, a stable emulsion can be obtained. Furthermore, the total content of emulsion (A), additives (B), and optional components (C) contained in the drug concentrate shall not exceed 100% by mass.

[0032] The drug stock solution preferably contains no other polymers other than the polymer in the water-soluble vinyl polymer emulsion (A), or if it does contain other polymers, it is preferably in small amounts. The content of other polymers relative to the total mass of the drug stock solution is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. It may be zero.

[0033] <Manufacturing method> The chemical agent for the shield tunneling method in this embodiment (chemical stock solution) may be an emulsion (A) as the chemical stock solution, or an additive (B) and optional components (C) may be added to the emulsion (A) as needed to produce the chemical stock solution.

[0034] <Physical properties> The chemical agent (undiluted chemical solution) for the shield tunneling method in this embodiment has an electrical conductivity of 500 μS / cm or more when a 1% aqueous solution of the undiluted chemical solution is used. The conductivity of the 1% aqueous solution can be adjusted by changing the ratio of ionic monomers that alter the counterions. For example, increasing the proportion of ionic monomers in the polymer tends to increase the conductivity of the 1% aqueous solution.

[0035] If the conductivity of a 1% aqueous solution of the drug stock is 500 μS / cm or higher, the drug stock will have low viscosity, while the diluted solution will have high viscosity. For example, it is possible to create a shield tunneling agent (concentrated agent) in which the viscosity of the concentrated agent at 20°C is 800 mPa·s or less, and the viscosity of a 1% aqueous solution of the concentrated agent at 20°C is 200 mPa·s or more. If the viscosity of the concentrated chemical solution is below the upper limit, it offers excellent handling characteristics, such as pumpability, when used in shield tunneling. If the viscosity of the 1% aqueous solution is above the lower limit, it exhibits higher performance in preventing the aggregation of excavated soil and preventing soil adhesion to equipment. A concentrated chemical solution that satisfies both conditions is highly suitable for shield tunneling. The viscosity of the drug stock solution is preferably 800 mPa·s or less, more preferably 700 mPa·s or less, and even more preferably 600 mPa·s or less. On the other hand, the lower limit of the viscosity of the drug stock solution is not particularly limited, but from the viewpoint of storage stability, it is preferably 100 mPa·s or more, more preferably 200 mPa·s or more, and even more preferably 300 mPa·s or more. The viscosity of the 1% aqueous solution is preferably 200 mPa·s or more, more preferably 300 mPa·s or more, and even more preferably 600 mPa·s or more. On the other hand, the upper limit of the viscosity of the 1% aqueous solution is preferably 3000 mPa·s or less, more preferably 2000 mPa·s or less, and even more preferably 1500 mPa·s or less, from the viewpoint of handling properties.

[0036] <Mechanism of Action> The reason why the viscosity behavior described above is obtained when the conductivity of a 1% aqueous solution of the drug stock is 500 μS / cm or higher is not entirely clear, but it is thought to be due to the expansion of polymer chains caused by charge repulsion between ionic groups.

[0037] <Shield Tunneling Method> The shield tunneling agent of this embodiment is suitably used as a chemical agent for treating excavated soil generated by excavation in known shield tunneling methods. [Aspect 1] The shield tunneling method according to this embodiment includes a supply step of supplying a treatment liquid containing the chemical agent for the shield tunneling method of this embodiment so as to mix with the excavated soil. In this embodiment, the treatment solution preferably contains a shield tunneling agent (concentrated agent solution) and water (dilution water). The content of the concentrated agent solution relative to the total mass of the treatment solution is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.01 to 1% by mass. It is preferable to have a mixing step before the supply step in which the drug concentrate and dilution water are mixed to prepare the treatment solution. The supply process can be carried out by known methods. For example, it may be a process of supplying the processing liquid to one or more locations selected from the cutter, chamber, and screw conveyor of the shielding machine. The processing liquid may be prepared by adding water to a stirring tank and stirring it to a predetermined concentration. The supply process may be a process of directly injecting the liquid from a stirring tank connected to the shielding machine at a predetermined injection rate. The concentration of the treatment solution may be adjusted depending on the type of ground and the soil removal conditions (concentration of the treatment solution, injection rate, etc.). If the required performance is met under the soil removal conditions, the concentration of the treatment solution, injection rate, etc. may be adjusted to reduce them as much as possible from the perspective of reducing environmental impact.

[0038] [Aspect 2] The chemical agent for shield tunneling in this embodiment can also be applied to bubble shield tunneling. In the bubble shield tunneling method, a creamy bubble (a fluid composed of aggregated fine bubbles) is supplied to mix with the excavated soil. Mixing the bubbles with the excavated soil has the effect of increasing the fluidity of the excavated soil and preventing soil from adhering to the equipment.

[0039] The shield tunneling method according to this embodiment includes a supply step of supplying a treatment liquid containing the shield tunneling agent of this embodiment and bubbles produced by foaming a diluted foaming agent, so as to mix with the excavated soil. In this embodiment, the treatment solution preferably contains a shield tunneling agent (concentrated agent solution) and water (dilution water). The content of the concentrated agent solution relative to the total mass of the treatment solution is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.01 to 1% by mass. In this embodiment, the concentration of the foaming agent in the diluted foaming agent solution is preferably 0.001 to 5% by mass, more preferably 0.01 to 3% by mass, and even more preferably 0.1 to 1% by mass, based on solid content. The foaming process, in which the diluted foaming agent solution is foamed, can be carried out by known methods. For example, it may be a process in which compressed air is used to foam the solution just before the working face. In the foaming process, the foaming ratio (related to the strength of the bubbles) may be adjusted. The foaming ratio may also be adjusted depending on the type of ground and the condition of the excavated soil. The mixing order with the excavated soil is not limited; either the bubbles or the treatment liquid may be mixed first, or they may be mixed simultaneously. The supply process can be carried out by known methods. For example, it may be a process of supplying one or both of the treatment liquid and the bubbles to one or more locations selected from the cutter, chamber, and screw conveyor of the shield machine.

[0040] The shield tunneling method of this embodiment may include a supply step of supplying bubbles, which are generated by foaming a treatment liquid containing the shield tunneling agent and foaming agent of this embodiment, so as to mix with the excavated soil. In this embodiment, the treatment solution preferably contains a shield tunneling agent (undiluted agent), a foaming agent, and water (dilution water). In this embodiment, the content of the undiluted drug solution relative to the total mass of the treatment solution is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, and even more preferably 0.01 to 1% by mass. The foaming agent content relative to the total mass of the treatment solution is preferably 0.001 to 5% by mass, more preferably 0.01 to 3% by mass, and even more preferably 0.1 to 1% by mass, in terms of solid content. Before the supply step, there may be a mixing step in which the drug stock solution, foaming agent, and dilution water are mixed to prepare the treatment solution, and a foaming step in which the treatment solution is foamed to prepare bubbles. In the mixing process, there are no particular restrictions on the order in which the drug concentrate, foaming agent, and dilution water are mixed. For example, a first solution may be prepared in advance by diluting the drug concentrate with water, and a second solution may be prepared by diluting the foaming agent with water. The first and second solutions may then be mixed to prepare the treatment solution. The foaming process, which involves foaming the treatment liquid, can be carried out by known methods. For example, it may be a process that uses compressed air to foam the liquid just before the working face. In the foaming process, the foaming ratio (related to the strength of the bubbles) may be adjusted. The foaming ratio may also be adjusted depending on the type of ground and the condition of the excavated soil. The supply process can be carried out by known methods. For example, it may be a process of supplying the bubbles to one or more locations selected from the cutter, chamber, and screw conveyor of the shielding machine.

[0041] [Foaming agent] The foaming agent preferably contains the following components (D) and (E). (D) Ingredient: Anionic surfactant. (E) Components: Alcohols having an aliphatic hydrocarbon group with 8 to 20 carbon atoms. Component (D) contributes to the formation of bubbles, and the addition of component (E) further strengthens the bubbles. The presence of component (E) in the bubbles further promotes the hydrophobicity of soil particles, thereby increasing the cohesive efficiency of excavated soil.

[0042] [(D) component] Component (D) is an anionic surfactant, preferably an alkyl ether sulfate salt. Component (D) may be used alone or in combination of two or more. As the alkyl ether sulfate salt, compound (D1) represented by the following general formula (d1) is preferred. R 6 O(AO) m SO3X ···(d1) In general formula (d1), R 6 represents a hydrocarbon group with 8 to 18 carbon atoms, AO represents a linear or branched alkylene oxide unit with 2 to 4 carbon atoms, m represents the average number of moles of AO added, which is a number between 0.1 and 8, and X represents a cation.

[0043] In general formula (d1), m is preferably between 0.1 and 5. R 6 The number of carbon atoms is preferably 10 to 14, and more preferably 12 to 14, from the viewpoint of solubility in water and foaming ability.6 A linear or branched alkyl group is preferred. AO is preferably an ethylene oxide unit. X is a cation that forms a water-soluble salt. Examples of salts include alkali metal salts, alkaline earth metal salts, ammonium salts, and mono, di, and trialkylammonium salts. Sodium salts are preferred.

[0044] Examples of compound (D1) include polyoxyalkylene dodecyl ether sulfate, polyoxyalkylene lauryl ether sulfate, polyoxyalkylene cetyl ether sulfate, polyoxyalkylene myristyl ether sulfate, polyoxyalkylene palmityl ether sulfate, polyoxyalkylene stearyl ether sulfate, and polyoxyalkylene oleyl ether sulfate. Compound (D1) can also be obtained from commercially available products.

[0045] [(E) component] Component (E) is an alcohol having an aliphatic hydrocarbon group with 8 to 20 carbon atoms. The aliphatic hydrocarbon group may be linear or branched. Component (E) may be a primary alcohol, a secondary alcohol, or a tertiary alcohol. Component (E) may be a synthetic alcohol or a natural alcohol. (E) Component may be used alone or in combination of two or more.

[0046] As component (E), a compound represented by the following general formula (e1) (E1) is preferred. R 7 OH ···(e1) In general formula (e1), R 7 R represents a hydrocarbon group with 8 to 18 carbon atoms. 7 The number of carbon atoms is preferably 10 to 14, and more preferably 12 to 14, as this further enhances bubble stabilization when used in combination with component (D).

[0047] Examples of compound (E1) include octyl alcohol, dodecyl alcohol, lauryl alcohol, cetyl alcohol, myristyl alcohol, palmityl alcohol, and oleyl alcohol. Compound (E1) can also be obtained from commercially available products.

[0048] In the foaming agent, the mass ratio D / E, which represents the content of component (D) to the content of component (E), is preferably 50 / 50 to 95 / 5, and more preferably 60 / 40 to 90 / 10. When D / E is within the above range, the foam stability when mixed with soil is further enhanced.

[0049] The foaming agent may optionally contain one or more alcohols other than component (E) in order to improve the mixed solubility of component (D) and component (E). Examples include monohydric alcohols with 7 or fewer carbon atoms such as ethyl alcohol, glycols such as ethylene glycol, alkylene glycol ethers such as ethylene glycol monobutyl ether and ethylene glycol monoisobutyl ether. Furthermore, as optional components, surfactants other than component (D), thickeners, etc., may be included to the extent that they do not impair the effects of the present invention. The total content of components (D) and (E) relative to the total mass of the foaming agent may be 95% by mass or more, 96% by mass or more, 97% by mass or more, 98% by mass or more, 99% by mass or more, or 100% by mass. Foaming agents for the bubble shield tunneling method, containing components (D) and (E), are also available commercially. [Examples]

[0050] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description. (Raw materials used) <Monomers of water-soluble vinyl polymer (A1)> Acrylamide: Pure content of 99% by mass or more. 80% Acrylic Acid: Aqueous solution of acrylic acid, 80% by mass. <Oil agent (A2)> Mineral oil: ENEOS Corporation, "Naphthezol", 100% by mass. <Water(A3)> Added water: Ion-exchanged water. <Other ingredients (A4)> Hypermer B-246: Product name, manufactured by Croda, nonionic surfactant, purity 90% by mass. Sorbitan monolaurate: nonionic surfactant, 100% by mass. 40% sodium hydroxide: Aqueous solution of sodium hydroxide, 40% by mass. Azobisisobutyronitrile: polymerization initiator, 98% by mass. Polyoxyethylene alkyl ether: nonionic surfactant, in formula (a1), R 1 is an alkyl group with 12 carbon atoms, R 2 A compound in which is a hydrogen atom, AO is an ethylene oxide unit, and p is 9, with a purity of 99% by mass.

[0051] <Additive (B)> (B1-1): Polyoxyethylene sorbitan monolaurate, manufactured by Tokyo Chemical Industry Co., Ltd., product name "Twin 20", purity 100% by mass, in formula (b1), R 3 A compound in which C1 is a linear alkyl group with 11 carbon atoms, AO is an ethylene oxide unit, and the sum of q, r, s, and t is an average of 20. (B1-2): Polyoxyethylene sorbitan oleate, manufactured by Tokyo Chemical Industry Co., Ltd., product name "Twin 80", purity 100% by mass, in formula (b1), -R 3 -C7H 14 CH=CHC7H 14 A compound in which CH3,AO is an ethylene oxide unit, and the sum of q, r, s, and t is an average of 20. (B2-1): Alkyl glycoside, manufactured by BASF, product name "Glucopon 215UP", purity 64% by mass, in formula (b2), one R 4 is a hydroxyalkyl group with 1 carbon atom, the remaining R 4 is a hydroxyl group, R 5 A compound in which the first element is a linear alkyl group having 8 to 10 carbon atoms. (B2-1): Alkyl glycoside, manufactured by BASF, product name "Glucopon 650EC", purity 52% by mass, in formula (b2), 1 R 4 is a hydroxyalkyl group with 1 carbon atom, the remaining R 4 is a hydroxyl group, R 5 A compound in which the first element is a linear alkyl group having 8 to 16 carbon atoms.

[0052] (Manufacturing Example 1: Manufacturing of water-soluble vinyl polymer emulsion (A)) Emulsion (A'-1) was prepared using the formulation shown in Table 1. First, 464.7 parts by mass of mineral oil, 3.3 parts by mass of Hypermer B-246 and 23.0 parts by mass of sorbitan monolaurate were charged into a reaction vessel equipped with a stirring device. Next, an aqueous monomer solution consisting of 289.8 parts by mass of acrylamide, 91.8 parts by mass of 80% acrylic acid, 51.7 parts by mass of 40% sodium hydroxide, and 54.5 parts by mass of ion-exchanged water was added. After purging the reaction vessel with nitrogen, 0.2 parts by mass of azobisisobutyronitrile was added as a polymerization initiator, and the reaction was continued at 45°C. Then, 21.0 parts by mass of polyoxyethylene alkyl ether was added to obtain a W / O emulsion (A'-1). Table 1 shows the content of each component (pure) of water-soluble vinyl polymer (A1), oil (A2), water (A3), and polyoxyethylene alkyl ether relative to the total mass of raw materials used in emulsion (A). Table 1 shows the molar ratios of acrylamide / acrylic acid and acrylic acid / sodium hydroxide in monomer aqueous solutions. Table 1 shows the purity, viscosity, and weight-average molecular weight of the obtained emulsion (A) and the water-soluble vinyl polymer (A1). The viscosity of emulsion (A) was measured using a B-type viscometer after adjusting the temperature of emulsion (A) to 20°C, under the conditions of a rotation speed of 60 rpm and a measurement time of 60 seconds.

[0053] (Manufacturing Examples 2-4: Manufacturing of water-soluble vinyl polymer emulsion (A)) Emulsions (A'-2), (A-3), and (A-4) were manufactured in the same manner as in Manufacturing Example 1, except that the amounts of each raw material used were changed as shown in Table 1. All emulsions were of the W / O type.

[0054] (Manufacturing Example 5: Manufacturing of water-soluble vinyl polymer emulsion (A)) In this example, water was added to the W / O type emulsion (A-4) obtained in Production Example 4, using the formulation shown in Table 1, and mixed to produce a milky liquid water-soluble vinyl polymer emulsion (A-5).

[0055] [Table 1]

[0056] (Comparative Examples 1 and 2 and Examples 1-7) The chemical agent (concentrate) for shield tunneling was manufactured using the formulations shown in Table 2. The amounts in the table include solvents and other components, not just the pure content. Blank spaces in the table indicate that the chemical was not included. In Comparative Examples 1 and 2 and Examples 1 to 3, the water-soluble vinyl polymer emulsion (A) obtained in the above production example was used as the drug stock solution. In Examples 4-7, the water-soluble vinyl polymer emulsion (A-4) obtained in Production Example 4 was mixed with the additive (B) shown in the table to produce a drug stock solution. The obtained drug stock solution was diluted with water to prepare a 1% aqueous solution, and its conductivity was measured. The results are shown in Table 2.

[0057] (evaluation) The viscosity behavior of the obtained drug stock solution was evaluated using the following method. The results are shown in Table 2. The viscosity of the undiluted chemical solution obtained in each case, and the viscosity of a 1% aqueous solution obtained by diluting the undiluted chemical solution with water, were measured. The suitability of the shield tunneling method was evaluated according to the following criteria. ◎: The viscosity of the undiluted drug solution is 800 mPa·s or less, and the viscosity of the 1% aqueous solution is 600 mPa·s or more. ○: The viscosity of the undiluted drug solution is 800 mPa·s or less, and the viscosity of the 1% aqueous solution is 300 mPa·s or more and less than 600 mPa·s. △: The viscosity of the undiluted drug solution is 800 mPa·s or less, and the viscosity of the 1% aqueous solution is 200 mPa·s or more and less than 300 mPa·s. ×: The viscosity of the undiluted drug solution exceeds 800 mPa·s, or the viscosity of the 1% aqueous solution is less than 200 mPa·s.

[0058] [Table 2]

[0059] As shown in the results in Table 2, shield tunneling agents with an electrical conductivity of 500 μS / cm or higher in a 1% aqueous solution have a low viscosity of 800 mPa·s or less in the undiluted solution, and a high viscosity when diluted, demonstrating excellent suitability for shield tunneling.

[0060] <Example 8> The suitability of the shield tunneling method was evaluated by measuring the cohesiveness of the soil when the chemicals shown in Example 3 of Table 2 were added to simulated soil mixed with bubbles generated by foaming a diluted foaming agent. (Simulated soil) A mixture of 5% by mass of powdered clay (manufactured by Kanto Kasei Co., Ltd., product name "Tochikure"), 20% by mass of silica sand No. 7, and 75% by mass of silica sand No. 5 was prepared to create a simulated soil with a water content of 13.3%. (Test method) A foaming agent containing 26% by mass of an anionic surfactant and 4.8% by mass of a higher alcohol with 12 carbon atoms was used. After diluting the foaming agent to a concentration (on a solid content basis) of 0.5% by mass, it was foamed at a foaming ratio of 6 and added to simulated soil at an injection rate of 20% and mixed. The cohesiveness of the resulting foamed soil mixture was evaluated. The injection rate was the volume % of the foam relative to the simulated soil, and the foaming ratio was calculated using Equation 1 by measuring the weight Ag and volume B ml of the foam. Expansion ratio (times) = (Volume of bubbles B ml) / (Weight of bubbles Ag) ... Equation 1 Next, the chemicals shown in Example 3 of Table 2 were diluted to a concentration of 1% by mass, then added to the aerated soil mixture at an injection rate of 10% and mixed. The cohesiveness of the simulated soil was then evaluated. The injection rate is the volume percentage of the diluted solution relative to the volume of the aerated soil mixture. (evaluation) The cohesiveness of the simulated soil was measured using the table flow test method specified in JIS R5201. If the flow value of the simulated soil was smaller than that before chemical addition, it was evaluated as having excellent suitability for shield tunneling. (result) The flow value of the foamed soil mixture before chemical addition was 147 mm, while the flow value after chemical addition was 102 mm. From these results, it can be seen that the chemical agent shown in Example 3 of Table 2 exhibits excellent soil cohesiveness even when used in combination with a foaming agent, and is highly suitable for the foamed shield tunneling method.

Claims

1. A chemical agent for shield tunneling that contains a water-soluble vinyl polymer emulsion (A), A shield tunneling agent wherein the conductivity of a 1% by mass aqueous solution of the shield tunneling agent is 500 μS / cm or more.

2. Furthermore, the chemical agent for shield tunneling according to claim 1, comprising one or more additives (B) selected from the group consisting of a compound (B1) represented by the following general formula (b1) and a compound (B2) represented by the following general formula (b2). 【Chemistry 1】 (In the formula, R ３ (where represents an alkyl or alkenyl group with 8 to 20 carbon atoms, AO independently represents an alkylene oxide unit with 2 to 4 carbon atoms, q, r, s, and t represent the average number of moles of AO added, and the sum of q, r, s, and t is a number between 15 and 25.) 【Chemistry 2】 (In the formula, R ４ Each of these independently represents a hydroxyl group or a hydroxyalkyl group having 1 to 3 carbon atoms, R ５ (This represents an alkyl group with 6 to 20 carbon atoms.)

3. The viscosity of the aforementioned shield tunneling agent at 20°C is 800 mPa·s or less, and The shield tunneling agent according to claim 1, wherein the viscosity of a 1% by mass aqueous solution of the shield tunneling agent at 20°C is 200 mPa·s or more.

4. A shield tunneling method comprising the step of supplying a treatment liquid containing the chemical agent for shield tunneling described in any one of claims 1 to 3 so as to mix with excavated soil.

5. A shield tunneling method comprising the step of supplying the chemical agent for shield tunneling described in any one of claims 1 to 3 and bubbles produced by foaming a diluted solution of a foaming agent, so as to mix with excavated soil.

6. The shield tunneling method according to claim 5, wherein the foaming agent comprises the following component (D) and component (E). (D) Component: Anionic surfactant. (E) Component: An alcohol having an aliphatic hydrocarbon group with 8 to 20 carbon atoms.

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