JP2024072904A - Foaming material for bubble shield method - Google Patents

Abstract

To provide a foaming material for bubble shield method that creates bubbles that are resistant to defoaming and highly stable.SOLUTION: A foaming material for bubble shield method comprises (A) an anionic surfactant, (B) at least one selected from the group consisting of ampholytic surfactants and amine oxide surfactants, and (C) a C8-30 aliphatic alcohol.SELECTED DRAWING: Figure 1

Description

The present invention relates to a foaming material for air bubble shield construction.

In the shield tunneling method, a mud-adding material is injected into the tunnel face and chamber, giving the excavated soil (mixed soil) plastic fluidity. This mixed soil fills the chamber, maintaining balance against earth pressure and water pressure, while allowing the soil to be smoothly discharged outside the machine. A type of this method in which air bubbles are injected as a mud-adding material is called the air bubble shield method.

The foam to be injected is selected according to the particle size of the target soil (Patent Document 1). In general, when there is a certain amount of fine particles, type A foam is mainly composed of an anionic surfactant; for sandy to gravelly soil with a small amount of fine particles, type B foam is made by mixing a powdered thickener such as carboxymethylcellulose (CMC) with the foaming agent stock solution used in type A and foaming to generate highly viscous foam, which compensates for the lack of fine particles by its viscosity; and for coarse gravelly soil, type C foam is made by spraying a gelling agent on the thickener during foaming to generate hard and very strong foam, which firmly holds the gravel together.
For B and C type foams, in addition to the equipment required for A type, a separate facility for dissolving powder is required when preparing the foaming agent solution. While the foaming ratio can be changed freely with A type foams, B type foams (and C type foams) containing a thickener have a high viscosity of the foaming agent solution, making them difficult to foam and limiting the foaming ratio to about 6 times, and therefore require a larger amount of foaming agent solution than A type foams. In addition, in order to ensure foaming properties, a separate additive may be required (Patent Document 2).

JP 2014-092018 A JP 2014-234484 A

Air Bubble Shield Method Technical Documents Shield Method Technology Association (http://shield-method.gr.jp/wp/wp-content/uploads/doc_tec_rf.pdf)

During shield tunneling, if the fine particles in the ground suddenly decrease or there is a large amount of gravel due to alternating layers of sand and gravel that were not anticipated in the initial geological survey, it may be necessary to change from type A foam to type B foam. In such cases, it is necessary to prepare two agents, so new equipment for type B foam (dilution water tank, mixing and dilution equipment such as dissolving tank, thickener storage tank and supply equipment, etc.) is required. However, since most shield tunneling methods are carried out in narrow spaces in urban areas, it is difficult to secure space for the equipment. Even if the equipment can be introduced, it takes a significant amount of time to secure and install the equipment, and construction must be stopped during that time. Therefore, there was a need for an agent that has the effects of foaming and thickening in one agent without requiring new equipment.

As a result of intensive research, the inventors of the present application have newly discovered that a foaming agent containing at least one selected from the group consisting of anionic surfactants or amphoteric surfactants and amine oxide type surfactants, a hydrophobic film agent, and a specific compound can generate bubbles that are difficult to defoam and have excellent stability.

Therefore, the present invention is as follows.
[1] (A) an anionic surfactant;
(B) at least one selected from the group consisting of amphoteric surfactants and amine oxide surfactants,
(C) an aliphatic alcohol having 8 to 30 carbon atoms;
A foaming material for air bubble shield construction method.
[2] The foaming material for the air bubble shield construction method described in [1] above, wherein the (A) component is at least one selected from α-olefin sulfonate, internal olefin sulfonate, alkane sulfonate, α-sulfofatty acid ester salt, alkyl sulfosuccinate di-salt, and dialkyl sulfosuccinate.
[3] A foaming material for the air bubble shield construction method described in [1] or [2], further containing (D) an organic solvent.

The present invention has produced a foaming material for the air bubble shield construction method that is difficult to defoam and has excellent stability.

Schematic diagram of a shield machine

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not necessarily limited to these.
The objects, features, advantages, and ideas of the present invention will be apparent to those skilled in the art from the description of this specification, and those skilled in the art can easily reproduce the present invention from the description of this specification.
The embodiments and specific examples of the invention described below are preferred embodiments of the present invention and are shown for illustrative or explanatory purposes, and are not intended to limit the present invention thereto.
It will be apparent to those skilled in the art that various changes and modifications can be made based on the description of the present specification within the spirit and scope of the present invention disclosed herein.

First, an overview of the shield machine used in the air bubble shield method will be described.
As shown in Figure 1, the shield machine 1 used in this construction method includes a skin plate 2, a partition wall 3, a cutter 4, a cutter motor 5, an air bubble injection pipe 6, a screw conveyor 7, and an earth pressure sensor 8.

The skin plate 2 is a tubular steel member that forms the outer shell of the shield machine 1. The partition wall 3 is provided on the skin plate 2 and defines a chamber 9 in the front portion of the skin plate 2. The cutter 4 is a part that excavates the ground by rotation and is disposed forward of the skin plate 2. The cutter motor 5 is a drive source for rotating the cutter 4 and is provided on the rear side of the partition wall 3. The drive force of the cutter motor 5 is transmitted to the cutter 4 via the support arm 10.

The air bubble injection tube 6 is a member that guides shaving cream-like fine air bubbles obtained by foaming the foaming agent solution in a foaming device (not shown). Since the tip of the air bubble injection tube 6 is located in front of the cutter 4, the guided fine air bubbles are injected toward the cutter 4. The excavated soil excavated by the cutter 4 is mixed with air bubbles by the rotation of the cutter 4, increasing its fluidity, and flows into the chamber 9. In the chamber 9, the presence of air bubbles suppresses the adhesion of the excavated soil to the wall surface. In addition, the air bubbles get into the spaces between the soil particles, improving the water-stopping properties.
The fine bubbles may be injected directly into the chamber 9 or into both the cutter 4 and the chamber 9 .

Next, we will explain a foaming material for the air bubble shield construction method, which contains (A) an anionic surfactant, (B) at least one selected from the group consisting of amphoteric surfactants and amine oxide type surfactants, and (C) an aliphatic alcohol having 8 to 30 carbon atoms.

The anionic surfactant, component (A), is a base agent that arranges itself at the gas-liquid interface to form a foam film of gas bubbles.
Examples of the "anionic surfactant" include linear alkylbenzenesulfonic acid or its salt, α-olefin sulfonate (also referred to as AOS), internal olefin sulfonate (IOS, also referred to as inner olefin sulfonate), linear or branched alkyl sulfate, alkyl ether sulfate or alkenyl ether sulfate, alkyl group-containing alkane sulfonate, α-sulfofatty acid ester salt (also referred to as MES), alkyl sulfosuccinate di-salt, dialkyl sulfosuccinate, etc. Examples of salts of these anionic surfactants include alkali metal salts such as sodium and potassium, alkaline earth metal salts such as magnesium, and alkanolamine salts such as monoethanolamine, diethanolamine, and triethanolamine. The anionic surfactant may be used alone or in combination of two or more of these.

Of the anionic surfactants which are the component (A) above, alkyl ether sulfates, α-olefin sulfonates, and internal olefin sulfonates are preferred, with alkyl ether sulfates being more preferred.
The amount of component (A) is preferably 3 to 40 mass % relative to the total mass of the foaming material for the air bubble shield construction method, and more preferably 10 to 30 mass %.

At least one surfactant selected from the group consisting of amphoteric surfactants and amine oxide surfactants, which is component (B), is a base material that stabilizes the foam film of air bubbles together with component (A).
Examples of the "amphoteric surfactant" include alkyl betaine type, alkyl amide betaine type, imidazoline type, alkyl amino sulfone type, alkyl amino carboxylic acid type, alkyl amide carboxylic acid type, amide amino acid type, and phosphoric acid type. The amphoteric surfactant is preferably a betaine type. Specific examples of the betaine type include lauryl dimethyl amino acetic acid betaine, coconut alkyl dimethyl amino acetic acid betaine, coconut oil fatty acid amidopropyl betaine, lauric acid amidopropyl dimethyl amino acetic acid betaine, coconut alkyl amidopropyl dimethyl amino acetic acid betaine, coconut oil fatty acid amidopropyl dimethyl amino acetic acid betaine (cocamidopropyl betaine), and 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine. As the betaine type, coconut oil fatty acid amidopropyl dimethyl amino acetic acid betaine (cocamidopropyl betaine) is more preferable. The amphoteric surfactant may be one of these, or two or more of them may be used in combination.

Examples of "amine oxide surfactants" include dodecyl dimethylamine oxide, coconut alkyl dimethylamine oxide, decyl dimethylamine oxide, and tetradecyl dimethylamine oxide. The amine oxide surfactant may be used alone or in combination of two or more of these.

Of the at least one selected from the group consisting of amphoteric surfactants and amine oxide surfactants, which are the component (B), lauric acid amidopropyl dimethylaminoacetic acid betaine and coconut alkyl amidopropyl dimethylaminoacetic acid betaine are preferred, and coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine (cocamidopropyl betaine) is more preferred.
The amount of component (B) is preferably 0.1 to 20 mass % relative to the total mass of the foaming material for the air bubble shield construction method, and more preferably 1 to 10 mass %.

The aliphatic alcohol having 8 to 30 carbon atoms, which is the component (C), interacts with the components (A) and (B) to improve the viscosity of the foam film surface and form strong bubbles.
Examples of the aliphatic alcohol having 8 to 30 carbon atoms as component (C) include aliphatic alcohols having a hydrocarbon group having 8 to 30, 8 to 20, or 8 to 14 carbon atoms, such as monohydric alcohols such as octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, stearyl alcohol, nonadecyl alcohol, octenyl alcohol, decenyl alcohol, dodecenyl alcohol, tridecenyl alcohol, pentadecenyl alcohol, oleyl alcohol, gadoleyl alcohol, linoleyl alcohol, ethylcyclohexyl alcohol, propylcyclohexyl alcohol, octylcyclohexyl alcohol, and nonylcyclohexyl alcohol.
These aliphatic alcohols may be linear, branched, or cyclic, but linear alcohols are preferred, and myristyl alcohol, lauryl alcohol, decyl alcohol, and octyl alcohol are preferred. One of these may be used alone, or two or more of them may be used in combination.
The amount of component (C) is preferably 1 to 20 mass % relative to the total mass of the foaming material for the air bubble shield construction method, and more preferably 2 to 10 mass %.

<Optional ingredients>
[Organic solvent]
The foaming material according to the present invention may contain (D) an organic solvent (excluding the above-mentioned (C) component). The organic solvent may be used without limitation as long as it does not inhibit foaming and is easily soluble in water (also called a water-soluble solvent). For example, organic solvents such as monohydric alcohols having 2 to 4 carbon atoms, polyhydric alcohols having 2 to 6 carbon atoms, and glycol ether-based solvents may be used. Specific examples of such organic solvents include ethanol, propanol, butanol, isopropyl alcohol, propylene glycol, dipropylene glycol, isoprene glycol, hexylene glycol, 1,3-butanediol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and ethylene glycol monophenyl ether.
Of these, ethanol, dipropylene glycol, isoprene glycol, hexylene glycol, 1,3-butanediol, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether are preferred. As the water-soluble solvent, one of these may be used alone, or two or more of them may be used in combination.
The content of the organic solvent (D) is preferably 5 to 40 mass % relative to the total mass of the foaming material for the air bubble shield construction method, and more preferably 10 to 30 mass %.

[water]
The foaming material according to the present invention may contain water. The amount of the water agent is preferably 20 to 80% by mass, more preferably 30 to 60% by mass, based on the total mass of the foaming material for the air bubble shield construction method.

In the foaming material for the air bubble shield construction method of the present invention,
The amount of component (A) is preferably 30 to 60% by mass, and more preferably 35 to 50% by mass, based on the total mass (total mass) of components (A) to (D). This range is preferable because sufficient foaming properties and liquid stability can be obtained.
The amount of component (B) is preferably 1 to 40% by mass, and more preferably 1 to 30% by mass, based on the total mass (total mass) of components (A) to (D). This range is preferable because sufficient foaming properties and liquid stability can be obtained.
The amount of component (C) is preferably 1 to 30% by mass, and more preferably 1 to 15% by mass, based on the total mass (total mass) of components (A) to (D). This range is preferable because sufficient foaming properties and liquid stability can be obtained.
The amount of component (D) is preferably 20 to 60% by mass, and more preferably 30 to 50% by mass, based on the total mass (total mass) of components (A) to (D). This range is preferable because sufficient foaming properties and liquid stability can be obtained.

The foaming material for the air bubble shield construction method of the present invention is preferably diluted with water as appropriate before use.
The dilution ratio is preferably 4 to 199 times the total mass (total mass) of the foaming material for the air bubble shield construction method of the present invention (dilution ratio: 5 to 200 times), and more preferably 19 to 99 times the total mass (dilution ratio: 20 to 100 times). This range is preferable because sufficient foaming properties and foam stability can be obtained.

[Other additives]
The foaming agent of the present invention may contain suitable additives as long as they do not affect its function. Examples of additives include cationic surfactants, nonionic surfactants, polyethylene glycol, polymeric compounds, insolubilizers, chelating agents, thickeners, clay minerals, preservatives, etc. In particular, nonionic surfactants such as alkylene oxide adducts of aliphatic alcohols and alkanolamides are preferred because they improve the foaming properties and stability of bubbles.

The foaming material for the air bubble shield construction method of the present invention can also be used as a foaming material for other civil engineering or construction works where air bubbles that are difficult to defoam and have excellent stability are desired.
Other civil engineering or construction works include aerated excavation method, underground diaphragm wall method, mechanical mixing method, jet mixing method, lightweight embankment method, aerated concrete, aerated mortar, etc.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The unit of the blending amount shown in Tables 1 and 2 is "mass %", and each component is the amount of active ingredient.
The raw materials used in this example are as shown in <Raw Materials Used> below.

<Ingredients used>
[Component (A)]
A-1: Sodium lauryl sulfate (product name "Texapon OC-P", manufactured by BASF Japan Ltd.).
A-2: Triethanolamine lauryl sulfate (product name "Typol NLT-42", manufactured by Taiko Yushi Chemical Industry Co., Ltd.).
A-3: Sodium polyoxyethylene lauryl ether sulfate, EO = 1 mol (product name "Shinoline SPE-1150", manufactured by New Japan Chemical Co., Ltd.).
A-4: Sodium polyoxyethylene lauryl ether sulfate, EO = 2 mol (product name "Shinoline SPE-1250", manufactured by New Japan Chemical Co., Ltd.).
A-5: Sodium polyoxyethylene lauryl ether sulfate, EO = 3 mol (product name "Shinoline SPE-1350", manufactured by New Japan Chemical Co., Ltd.).
A-6: Sodium secondary alcohol alkoxylate sulfate ester, EO=3 mol (product name "Taipol SFES-326", manufactured by Taiko Yushi Chemical Industries Co., Ltd.).
A-7: Sodium secondary alcohol alkoxylate sulfate ester, EO=7 mol (product name "Taipol SFES-733", manufactured by Taiko Yushi Chemical Industries Co., Ltd.).
A-8: Sodium secondary alcohol alkoxylate sulfate ester, EO=12 mol (product name "Taipol SFES-1233", manufactured by Taiko Yushi Chemical Industries Co., Ltd.).
A-9: AOS, sodium tetradecene sulfonate (product name "Lipolan LB-440", manufactured by Lion Specialty Chemicals Co., Ltd.).
A-10: MES, sodium alpha sulfo fatty acid ester (product name "WILFAMES C 16 FR", manufactured by WILMAR).
A-11: IOS, an inner olefin sulfonate synthesized by the method described in Example 7 of JP-A-2001-247534.

[Component (B)]
B-1: Coconut fatty acid amidopropyl dimethylaminoacetic acid betaine (product name "Energycol C-30B", manufactured by Lion Specialty Chemicals Co., Ltd.).
B-2: Lauryl amidopropyl dimethylaminoacetic acid betaine (product name "Energycol L-30B", manufactured by Lion Specialty Chemicals Co., Ltd.).
B-3: Coconut alkyl dimethylamine oxide (product name: Cadenax DMC-W, manufactured by Lion Specialty Chemicals Co., Ltd.).
B-4: Tetradimethylamine oxide (product name "Kadenax DM 14D-N, manufactured by Lion Specialty Chemicals Co., Ltd.).

[Component (C)]
C-1: Myristyl alcohol (product name "Conol 1495", manufactured by New Japan Chemical Co., Ltd.).
C-2: Lauryl alcohol (product name "Conol 20P", manufactured by New Japan Chemical Co., Ltd.).
C-3: Decyl alcohol (product name "Conol 1098", manufactured by New Japan Chemical Co., Ltd.).
C-4: Octyl alcohol (product name "Conol 10WS", manufactured by New Japan Chemical Co., Ltd.).

[(D) Organic Solvent]
D-1: Dipropylene glycol D-2: Ethylene glycol monobutyl ether (product name "Butyl glycol", manufactured by Nippon Nyukazai Co., Ltd.)
D-3: Diethylene glycol monobutyl ether (product name "Butyl Diglycol", manufactured by Nippon Nyukazai Co., Ltd.)

<Creating bubbles>
The foaming agent liquids shown in Tables 1 and 2 were diluted with water to prepare 3% diluted solutions. The resulting diluted solutions were mixed with compressed air by a compressor at the same pressure in a cylinder filled with ceramic balls to cause foaming, resulting in foams with a foaming ratio of 10 times. The foaming ratio was calculated by measuring the mass Ag and volume Bml of the resulting bubbles using formula 1.

Expansion ratio (times) = (cell volume B ml) / (cell mass Ag) ... Equation 1

<Evaluation method>
The resulting foam was filled into a 1000 ml measuring cylinder and allowed to stand at room temperature. The amount of waste liquid (C ml) that accumulated at the bottom of the measuring cylinder as the foaming progressed over time was measured, and the foaming rate was calculated using Equation 2.

Defoaming rate (%) = (drainage volume C ml) / (1000/10) x 100 ... formula 2

When the defoaming rate 30 minutes after the creation of bubbles was less than 80%, it was rated as "good", and when it was 80% or more, it was rated as "poor".

<Results>
As is clear from Tables 1 and 2, all of Examples 1 to 21 had highly stable bubbles, and were rated as ◯. On the other hand, Comparative Examples 1 and 2 had bubbles that were easily defoamed and had low stability, and were rated as ×. In other words, these experimental results made it clear that the foaming material for the air bubble shield construction method of the present invention can produce bubbles with excellent stability.

1 ... Shield machine, 2 ... Skin plate, 3 ... Partition wall, 4 ... Cutter, 5 ... Cutter motor, 6 ... Air bubble injection pipe, 7 ... Screw conveyor, 8 ... Earth pressure sensor, 9 ... Chamber, 10 ... Support arm

Claims (3)

(A) an anionic surfactant;
(B) at least one selected from the group consisting of amphoteric surfactants and amine oxide surfactants,
(C) an aliphatic alcohol having 8 to 30 carbon atoms;
A foaming material for air bubble shield construction method. The foaming material for the air bubble shield construction method according to claim 1, wherein component (A) is at least one selected from α-olefin sulfonate, internal olefin sulfonate, alkane sulfonate, α-sulfofatty acid ester salt, alkyl sulfosuccinate di-salt, and dialkyl sulfosuccinate. The foaming material for the air bubble shield construction method according to claim 1 or 2, further comprising (D) an organic solvent.