Rock drilling method

Abstract

To provide a rock drilling method capable of reducing wear on a drilling bit.SOLUTION: The rock drilling method using a drilling machine includes supplying a drilling fluid which contains (A) an anionic surfactant having a molecular weight of 900 or less and water to a drilling site, and performing drilling.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for excavating rock masses.

Background Art

[0002] As a method for burying pipes or constructing tunnels in places such as urban areas where the construction occupation area is limited and consideration for the living environment is required, a non-excavation method that performs construction without excavating the ground surface is known. As a non-excavation method, for example, there is a jacking method, which is a method of pushing a jacking pipe provided with an excavator or a cutting edge at the front end from the rear with a pressing means such as a jack to push the jacking pipe into the ground.

[0003] Also, when excavating ground such as rock masses, various chemicals and auxiliary materials are used. Patent Document 1 addresses the problem of improving the dischargeability of drill cuttings and improving the drilling efficiency when drilling into the natural ground (especially cohesive natural ground) in tunnel construction and the like. It discloses a sludge-promoting agent for promoting sludge discharge from holes by adding it to the drilling water when drilling into the natural ground. The sludge-promoting agent contains at least one selected from naphthalenesulfonic acid formalin condensate salts, ligninsulfonate salts, and acrylic polymer salts having a weight average molecular weight of 500 to 50,000. Patent Document 2 relates to a roller bit (rotary cutting disc) provided in a shield excavator used for crushing and fracturing hard natural ground such as rock masses, and discloses the twisting (slipping) generated by revolving and rotating while contacting the natural ground and the eccentric wear of the outer ring portion of the roller bit caused by the slipping. Patent Document 3 relates to a method for reducing friction between at least two solid bodies, and discloses a method including a step of providing a coating containing at least one polymer on the surface of at least one of the solid bodies and a step of supplying a liquid onto the coating. As a combination of the coating and the liquid, a poly(acrylic acid) polymer or its derivative having a predetermined molecular weight and water or an aqueous medium are disclosed.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-79925 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-323780 [Patent Document 3] Japanese Patent Publication No. 2010-538106 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] The present invention relates to a method for excavating rock that can reduce wear of an excavation bit. [Means for Solving the Problems]

[0006] The present invention relates to a method for excavating rock using an excavator, wherein the excavation site is supplied with an excavation fluid containing (A) an anionic surfactant having a molecular weight of 900 or less [hereinafter referred to as component (A)] and water, and excavation is performed. [Effects of the Invention]

[0007] The present invention provides a method for excavating rock that can reduce wear of an excavation bit. According to the excavation method of the present invention, rock can be efficiently excavated using an excavation bit. [Modes for Carrying Out the Invention]

[0008] In an exemplary embodiment, the excavation fluid used in the present invention [hereinafter also referred to as the excavation fluid of the present invention] contains (A) an anionic surfactant having a molecular weight of 900 or less and water. Also, in another exemplary embodiment, the excavation fluid of the present invention includes a friction reducing composition [hereinafter also referred to as the friction reducing composition of the present invention] containing (A) an anionic surfactant having a molecular weight of 900 or less and water.

[0009] The excavation fluid of the present invention may be supplied between the excavation site (face) and the excavator. The excavation fluid of the present invention may contain mud.

[0010] (Component (A) is an anionic surfactant having a molecular weight of 900 or less. From the viewpoint of the friction reduction effect, the molecular weight of component (A) is preferably 700 or less, more preferably 500 or less, still more preferably 450 or less, even more preferably 350 or less, and from the viewpoint of the friction reduction effect, the molecular weight is preferably 100 or more, and more preferably 200 or more.)

[0011] (Component (A) is preferably one or more anionic surfactants selected from compounds having a hydrocarbon group and a group selected from a sulfonic acid group, a sulfate ester group, and a phosphate ester group. That is, component (A) is preferably one or more anionic surfactants having a molecular weight of 900 or less and selected from compounds having a hydrocarbon group and a group selected from a sulfonic acid group, a sulfate ester group, and a phosphate ester group.) (The sulfonic acid group, sulfate ester group, and phosphate ester group each include a group in the form of a salt.)

[0012] (The hydrocarbon group constituting component (A) preferably has 30 or fewer carbon atoms, more preferably 26 or fewer carbon atoms, still more preferably 20 or fewer carbon atoms, and preferably 6 or more carbon atoms. That is, component (A) is preferably one or more anionic surfactants selected from compounds having a hydrocarbon group within the above carbon number range and a group selected from a sulfonic acid group, a sulfate ester group, and a phosphate ester group.)

[0013] (Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an aralkyl group, an aryl group, and an aryl group having a substituent [hereinafter referred to as a substituted aryl group]. The hydrocarbon group is preferably a group selected from an alkyl group, an alkenyl group, and a substituted aryl group, and more preferably a group selected from an alkyl group and an alkenyl group.)

[0014] The alkyl group is preferably an aliphatic alkyl group, more preferably a linear aliphatic alkyl group, and even more preferably a linear primary aliphatic alkyl group. The alkenyl group is preferably an aliphatic alkenyl group, more preferably a linear aliphatic alkenyl group, and even more preferably a linear primary aliphatic alkenyl group. Here, the term "primary" for the alkyl group or alkenyl group means that among the carbon atoms of the alkyl group or alkenyl group, the carbon atom bonded to another group is a primary carbon atom.

[0015] An aralkyl group is an alkyl group in which one of the hydrogen atoms of the alkyl group is substituted with an aryl group, and examples include a benzyl group and a phenethyl group.

[0016] An aryl group is a substituent containing an aromatic ring, and examples include a phenyl group and a naphthyl group.

[0017] A substituted aryl group is an aryl group in which the hydrogen atom of the aromatic ring is substituted with a substituent, and examples include an aryl group in which one, two, or three hydrogen atoms of the aromatic ring are substituted with a hydrocarbon group. Further, the substituted aryl group includes a substituted aryl group having 13 to 30 carbon atoms. The aryl group of the substituted aryl group is preferably a phenyl group or a naphthyl group. Examples of the hydrocarbon group that is a substituent of the substituted aryl group include an alkyl group and an alkenyl group.

[0018] When the aryl group portion of the substituted aryl group is a phenyl group, the hydrocarbon group that is a substituent is preferably 7 or more carbon atoms, more preferably 10 or more carbon atoms, and preferably 24 or less carbon atoms, more preferably 14 or less carbon atoms. When the aryl group portion of the substituted aryl group is a naphthyl group, the hydrocarbon group that is a substituent is preferably 3 or more carbon atoms, more preferably 4 or more carbon atoms, and preferably 20 or less carbon atoms, more preferably 10 or less carbon atoms. The hydrocarbon group that is a substituent of the substituted aryl group is preferably an alkyl group or an alkenyl group.

[0019] Examples of the substituted aryl group include a phenyl group substituted with a linear or branched alkyl group having preferably 7 or more, more preferably 10 or more, and preferably 24 or less, more preferably 20 or less, still more preferably 14 or less carbon atoms, and a naphthyl group substituted with a linear or branched alkyl group having preferably 3 or more, more preferably 4 or more, and preferably 20 or less, more preferably 10 or less carbon atoms. The substituted aryl group is preferably a group selected from an octylphenyl group, a nonylphenyl group, a decylphenyl group, a dodecylphenyl group, a hexadecylphenyl group, a tert-butylnaphthyl group, a propylnaphthyl group, and an octylnaphthyl group, and more preferably a group selected from a dodecylphenyl group and a tert-butylnaphthyl group.

[0020] (Component (A) may contain an oxyalkylene group. Examples of the oxyalkylene group include an oxyethylene group and an oxypropylene group, and an oxyethylene group is preferred. The added molar number of the oxyalkylene group is preferably 1 or more, more preferably 2 or more, and preferably 5 or less, more preferably 4 or less.

[0021] (Component (A) is preferably one or more anionic surfactants selected from the following (A1) to (A5). One or more anionic surfactants selected from the following (A1) to (A5) may each have a molecular weight within the above range.

[0022] (A1) Alkylbenzenesulfonic acid or its salt [hereinafter referred to as component (A1)] (A2) Alkylnaphthalenesulfonic acid or its salt [hereinafter referred to as component (A2)] (A3) Alkyl sulfosuccinate or its salt [hereinafter referred to as component (A3)] (A4) Polyoxyalkylene alkyl ether phosphate or its salt [hereinafter referred to as component (A4)] (A5) Polyoxyalkylene alkyl ether sulfate or its salt [hereinafter referred to as component (A5)]

[0023] (A1) component includes, for example, an alkylbenzene sulfonic acid having an alkyl group with 8 to 16 carbon atoms or a salt thereof. From the perspective of the friction reduction effect, the alkyl group substituting the benzene ring of the (A1) component preferably has 10 or more carbon atoms, more preferably 16 or less, and still more preferably 14 or less. Examples of the alkyl group substituting the benzene ring of the (A1) component include a linear alkyl group and a branched alkyl group. The (A1) component preferably has one alkyl group. The salt of the (A1) component is preferably an alkali metal salt such as a sodium salt or a potassium salt, and more preferably a sodium salt.

[0024] (A1) component preferably includes an alkylbenzene sulfonic acid having a linear alkyl group with 8 or more, more preferably 10 or more, and 16 or less, still more preferably 14 or less carbon atoms or a salt thereof from the perspective of the friction reduction effect.

[0025] (A2) component includes, for example, an alkylnaphthalene sulfonic acid having an alkyl group with 1 to 6 carbon atoms or a salt thereof. From the perspective of the friction reduction effect, the alkyl group substituting the naphthalene ring of the (A2) component preferably has 2 or more carbon atoms, and more preferably 4 or less. Examples of the alkyl group substituting the naphthalene ring of the (A2) component include a linear alkyl group and a branched alkyl group. The (A2) component preferably has one alkyl group. The salt of the (A2) component is preferably an alkali metal salt such as a sodium salt or a potassium salt, and more preferably a sodium salt.

[0026] (A2) component preferably includes an alkylnaphthalene sulfonic acid having an alkyl group with 1 or more, more preferably 2 or more, and 6 or less, still more preferably 4 or less carbon atoms or a salt thereof from the perspective of the friction reduction effect.

[0027] (A3) component includes, as an example, alkyl sulfosuccinic acid having one or two alkyl groups with 6 to 12 carbon atoms or its salt. From the perspective of the friction reduction effect, the alkyl group of the (A3) component preferably has 8 or more carbon atoms, and more preferably 10 or less carbon atoms. Examples of the alkyl group of the (A3) component include linear alkyl groups and branched alkyl groups. The salt of the (A3) component is preferably an alkali metal salt such as sodium salt or potassium salt, and more preferably sodium salt.

[0028] (A3) component preferably includes alkyl sulfosuccinic acid having two branched alkyl groups with 6 or more, more preferably 8 or more, and 12 or less, more preferably 10 or less carbon atoms or its salt.

[0029] (A4) component includes, as an example, polyoxyalkylene alkyl ether phosphate ester having an alkyl group with 8 to 18 carbon atoms and an oxyalkylene group with an average addition mole number of 1 to 6 or its salt. From the perspective of the friction reduction effect, the alkyl group of the (A4) component preferably has 10 or more carbon atoms, and more preferably 14 or less carbon atoms. Examples of the alkyl group of the (A4) component include linear alkyl groups and branched alkyl groups. The oxyalkylene group is preferably an oxyethylene group or an oxypropylene group, and more preferably an oxyethylene group. From the perspective of the friction reduction effect, the average addition mole number of the oxyalkylene group is preferably 2 to 4. The salt of the (A4) component is preferably an alkali metal salt such as sodium salt or potassium salt, and more preferably potassium salt.

[0030] (A4) component preferably includes polyoxyethylene alkyl ether phosphate ester having a linear alkyl group with 8 or more, more preferably 10 or more, and 18 or less, more preferably 14 or less carbon atoms and an oxyethylene group with an average addition mole number of 1 or more, more preferably 2 or more, and 6 or less, more preferably 4 or less or its salt.

[0031] As the component (A5), examples include polyoxyalkylene alkyl ether sulfate ester having an alkyl group with 8 to 18 carbon atoms and an oxyalkylene group with an average addition mole number of 1 to 6, or a salt thereof. From the viewpoint of the friction reduction effect, the alkyl group of the component (A5) preferably has 10 or more carbon atoms, more preferably 14 or less carbon atoms. Examples of the alkyl group of the component (A5) include a linear alkyl group and a branched alkyl group. The oxyalkylene group is preferably an oxyethylene group or an oxypropylene group, more preferably an oxyethylene group. From the viewpoint of the friction reduction effect, the average addition mole number of the oxyalkylene group is more preferably 2 to 4. The salt of the component (A5) is preferably an alkali metal salt such as a sodium salt or a potassium salt, more preferably a sodium salt.

[0032] As the component (A5), polyoxyethylene alkyl ether sulfate ester having a linear alkyl group with 8 or more, further 10 or more, and 18 or less, 14 or less carbon atoms and an oxyethylene group with an average addition mole number of 1 or more, further 2 or more, and 6 or less, further 4 or less, or a salt thereof is preferable.

[0033] From the viewpoint of the friction reduction effect, the component (A) is preferably at least one selected from (A1), (A2), and (A3).

[0034] From the viewpoint of the friction reduction effect, the content of the component (A) in the drilling fluid of the present invention is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and preferably 3% by mass or less, more preferably 1.0% by mass or less, still more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less.

[0035] The drilling fluid of the present invention may contain the component (A) and water, and may optionally contain water. That is, in the present invention, as the drilling fluid of the present invention, a composition prepared by mixing the friction reduction composition containing the component (A) and water with water can be used. Further, the drilling fluid of the present invention may contain the friction reduction composition containing the component (A) and water, and may optionally contain water and mud. That is, in the present invention, as the drilling fluid of the present invention, a composition prepared by mixing the friction reduction composition containing the component (A) and water with water and mud can be used.

[0036] The content of the component (A) in the friction reduction composition of the present invention is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less.

[0037] Among the components other than water in the friction reduction composition of the present invention, the content of the component (A) may be preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and even more preferably 90% by mass or more. The friction reduction composition of the present invention may substantially contain 100% by mass of the component (A) among the components other than water.

[0038] The water content in the friction reduction composition of the present invention may be preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less.

[0039] Next, the drilling machine used in the present invention will be described. Examples of the drilling machine of the present invention include a drilling machine having a drilling bit [hereinafter also referred to as the drilling machine of the present invention]. The drilling machine of the present invention may be a drilling machine having a drilling bit and a supply means for the drilling fluid of the present invention.

[0040] Examples of the excavator of the present invention include excavators used in non-excavation methods such as the shield method and the propulsion method. That is, the excavation method of the present invention may be a non-excavation method, and may be a slurry propulsion method (also referred to as a slurry shield method). The excavator of the present invention may be a known excavator used in these methods. As the excavator of the present invention, for example, a shield machine such as a slurry shield can be used. In addition, a propulsion machine used in the propulsion method, an excavator for shaft excavation, etc. can be used.

[0041] Examples of the excavator of the present invention include an excavator including an excavator body, an excavation head installed on the excavator body, and rotational propulsion driving means for the excavation head, wherein the excavation head includes a head body, an excavation bit installed on the head body, an opening formed in the head body, and a partition disposed in the opening facing the excavation bit. The excavation bit is preferably a roller bit that excavates by rotational motion. The roller bit is not particularly limited, and specifically, roller cone bits, tricone bits, three-cone bits, fixed cutter bits, etc. can be mentioned. The selection of the bit is determined by the type of formation.

[0042] The present excavator may include elements other than those described above, such as a space (chamber) sandwiched between the excavation bit and the partition, a jack for propelling the excavator body (excavation head) in the advancing direction, a discharge device for the excavated rock mass, etc. The excavator body may be configured to include a cylindrical member that serves as a body portion. In the present excavator, any of a spoke-type or a faceplate-type head employed in a shield machine can be used as the excavation head. In the present excavator, a plurality of the excavation bits (also referred to as tips, etc.) are arranged on the front surface of the excavation head (also referred to as a cutter bit, etc.) body to excavate the face in the advancing direction. An excavation bit suitable for rock excavation is selected.

[0043] In the present invention, the drilling fluid of the present invention can be supplied to a drilling site, for example, a site where a drilling bit of a drilling machine contacts a rock formation, for drilling. In the present invention, for example, in the case of the slurry shield method, the drilling fluid of the present invention can be supplied to the drilling site (face) via the chamber. In the present invention, drilling is performed by supplying the drilling fluid of the present invention to a predetermined site while the drilling machine is operating.

[0044] In the present invention, for example, in the case of the slurry shield method, the drilling fluid of the present invention may be circulated in a path including a slurry storage tank, a mud delivery pipe connected to the slurry tank, the chamber connected to the mud delivery pipe, a mud discharge pipe connected to the chamber, and the slurry tank connected to the mud discharge pipe. In the said path, the drilling fluid of the present invention may be pressurized and pumped appropriately by a mud delivery pump connected to the mud delivery pipe, a mud discharge pump connected to the mud discharge pipe, etc. When the drilling fluid of the present invention contains mud, the concentration of the mud passing through the mud discharge pipe and the mud delivery pipe may be appropriately adjusted to a known concentration. In the present invention, the friction reduction composition of the present invention may be optionally added so that the drilling fluid of the present invention in the said path reaches the concentration of the predetermined component (A) described above.

[0045] The supply amount of the drilling fluid of the present invention is not particularly limited and can be appropriately selected according to the drilling machine and the drilling method. For example, the drilling fluid of the present invention can be supplied to a site where a rock formation contacts a drilling bit of a drilling machine at, for example, 0.1 L / min or more and 50 L / min or less for drilling.

[0046] The drilling method of the present invention can be performed by non-excavation methods such as, for example, the pipe-jacking method and the shield method. For these drilling methods, known methods, apparatuses, etc. can be used appropriately.

[0047] The subject of the present invention is bedrock, which is a rock mass that forms the basement. It is different from ground containing soil or clay. Examples of bedrock that is the subject of the present invention include sandstone, mudstone, phyllite, slate, agglomerate, conglomerate, chert, limestone, tuff, rhyolite, andesite, basalt, granite, diorite, gabbro, schist, gneiss, amphibolite, and greenstone. For example, it is known that the hardness of bedrock varies depending on the type of bedrock. The uniaxial compressive strength of the bedrock that is the subject of the present invention is set to 50MN / m from the viewpoint of more efficiently exerting the effect of suppressing the decrease in excavation efficiency. 2 More than 80MN / m is preferable. 2 More preferably, 100MN / m 2 More preferably, from the viewpoint of excavation, 300MN / m 2 Unconfined compressive strength of 100MN / m or less is preferable. 2 In hard rocks such as granite and rhyolite, where the excavation efficiency exceeds 100%, generally the excavation efficiency is significantly reduced. However, the method of the present invention can suppress the reduction in the excavation efficiency. EXAMPLES

[0048] Friction-reducing compositions were prepared containing the component (A) shown in the table at the concentrations shown in Tables 1 and 2 (the balance being water). In component (A), the number in parentheses following polyoxyethylene is the average number of moles of oxyethylene groups added.

[0049] <Method of measuring friction coefficient> The friction coefficient was measured using an HFRR tester (manufactured by PCS Instruments) when the friction reducing composition of the present invention was used. An HFRR disk (diameter 10 mm x thickness 3 mm, material ANSI E-52100 steel, part number Lower Specimen (Disc) -PCS-002804) and a test liquid were placed on the upper test dish attached to the tester, and an HFRR ball (diameter 6 mm, material ANSI E-52100 steel, part number Upper Specimen (Ball) -PCS-002834) was placed on the HFRR disk so as to contact the surface of the HFRR disk. Into the upper test dish with the HFRR disk installed, about 3 mL of a mixture of water and a friction-reducing composition at a predetermined concentration (referred to as Drilling Fluid 1 of the present invention), or a mixture of the following prepared muddy water and a friction-reducing composition at a predetermined concentration (referred to as Drilling Fluid 2 of the present invention) was poured so that the HFRR disk was completely immersed. The HFRR ball was placed at the measurement start position and it was confirmed that it was in contact with the surface of the HFRR disk. At this time, the water level from the contact point between the HFRR disk and the HFRR ball was about 3 mm. After the Drilling Fluid 2 in the upper test dish was stirred with a glass rod to ensure there was no precipitate, the friction coefficient was immediately measured. The smaller the numerical value of the friction coefficient, the higher the friction reduction effect. Also, Friction Coefficient 1 is due to Drilling Fluid 1 of the present invention, and Friction Coefficient 2 is due to Drilling Fluid 2 of the present invention.

[0050] The method for measuring the friction coefficient was carried out according to the following procedure. The test piece was heated and kept at 35°C for 2 minutes, then vibrated for 10 minutes under a load of 1,000 g, a frequency of 10 Hz, and a stroke length of 1,000 μm, and the friction coefficient at that time was measured.

[0051] Muddy water: Prepared by mixing 2 g of commercially available Kasaoka clay (「Kasaoka clay」(powder) (250 mesh) manufactured by Kanesan Kogyo Co., Ltd.) and 20 g of water and stirring with a glass rod for 1 minute.

[0052]

Table 1

[0053]

Table 2

[0054] From Table 1, it was confirmed that the friction between the HFRR disk and the HFRR ball could be reduced using the cutting fluid 1 containing 0.3% by mass of the component (A) (friction coefficient 1). From Table 1, it was confirmed that the cutting fluid 2 containing 0.3% by mass of the component (A) could reduce the friction between the HFRR disk and the HFRR ball even in the presence of mud (friction coefficient 2). From Table 2, it was confirmed that the friction between the HFRR disk and the HFRR ball could be reduced using the cutting fluid 1 containing 0.1% by mass of the component (A) (friction coefficient 1).

[0055] From Table 1, when the component (A) has an oxyalkylene group, there is a tendency for the effect to be relatively large with the friction coefficient 1 (cutting fluid 1), while there is a tendency for the effect to be relatively small with the friction coefficient 2 (cutting fluid 2). This is presumably because the oxyalkylene group interacts with the mud particles. And from the results of Table 1, it is speculated that when the friction coefficient 2 is measured using the cutting fluid 2 of the present invention containing the component (A) at the concentration of Table 2, it also shows a friction reduction effect in the same tendency as Table 1. From the results of Tables 1 and 2, it is judged that the method of the examples can reduce the wear of the cutting bit in the method of excavating rock using an excavator.

[0056] Also, in the slurry shield method, when any of the cutting fluids from Example 1-1 to Example 1-5 is circulated through a path including a slurry storage tank, a mud delivery pipe connected to the mud tank, a chamber connected to the mud delivery pipe, a mud discharge pipe connected to the front chamber, and the mud tank connected to the mud discharge pipe, and the cutting fluid is supplied to the face through the chamber, the friction when the cutting bit of the excavator bites into the rock is reduced, and the rock can be efficiently excavated. Further, when the cutting fluid is supplied to the face, the wear of the cutting bit of the excavator is suppressed, and the life of the bit is extended. The same applies to Example 2-1 to Example 2-5.

Claims

1. A method for excavating rock using an excavator, comprising: supplying an excavation fluid containing (A) an anionic surfactant having a molecular weight of 900 or less [hereinafter referred to as component (A)] and water to an excavation site to perform excavation; A method for excavating rock.

2. The method for excavating rock according to claim 1, wherein the excavation fluid is prepared by mixing the friction reduction composition containing component (A) and water with water.

3. The method for excavating rock according to claim 1, wherein the excavation fluid is prepared by mixing the friction reduction composition containing component (A) and water with water and mud.

4. The method for excavating rock according to any one of claims 1 to 3, wherein component (A) is at least one selected from compounds having a hydrocarbon group and a group selected from a sulfonic acid group, a sulfate ester group, and a phosphate ester group.

5. The method for excavating rock according to any one of claims 1 to 4, wherein component (A) is at least one selected from the following (A1) to (A5). (A1) Alkylbenzene sulfonic acid or a salt thereof (A2) Alkylnaphthalene sulfonic acid or a salt thereof (A3) Alkyl ester of sulfosuccinic acid or a salt thereof (A4) Polyoxyalkylene alkyl ether phosphate ester or a salt thereof (A5) Polyoxyalkylene alkyl ether sulfate ester or a salt thereof

6. The method for excavating rock according to claim 5, wherein component (A) is at least one selected from (A1), (A2), and (A3).

7. The method for excavating rock according to any one of claims 1 to 6, wherein the content of component (A) in the excavation fluid is 0.05% by mass or more and 3% by mass or less.

8. The excavator is an excavator having an excavation bit, and the excavation fluid is supplied to a portion where the rock contacts the excavation bit of the excavator to perform excavation. The method for excavating rock according to any one of claims 1 to 7.

9. The method for excavating rock according to any one of claims 1 to 8, wherein the excavation method is a non-excavation method.

10. The method for excavating rock according to any one of claims 1 to 9, wherein the excavation method is a slurry shield tunneling method.

11. The uniaxial compressive strength of the rock mass is 50 MN / m ２ or more, and the rock mass excavation method according to any one of claims 1 to 10.

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