Method of manufacturing root consolidation portion of pile

Abstract

To provide a method for producing a foot protection part of a pile excellent in filling property when the foot protection part of the pile is produced by injecting a hydraulic composition slurry into an excavated hole in a method for burying a concrete pile.SOLUTION: In a method for manufacturing a foot protection part of a pile, a hydraulic composition slurry containing a hydraulic powder, the following component (a) and water is injected into an excavated hole in a burying method of a concrete pile from the bottom of the excavated hole. One or more selected from an amphoteric surfactant and a cationic surfactant SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a base protection portion of a pile. [Background technology]

[0002] Hydraulic compositions such as concrete and mortar are used in various fields such as civil engineering and construction. For example, in a method for embedding precast concrete piles, a slurry containing hydraulic powder is used as an excavation stabilizing liquid, a pile periphery fixing liquid, etc. In the method of embedding precast concrete piles in the foundation work for the construction of a structure, etc., there are various methods, such as a method in which the ground is excavated down to the bearing layer using a drilling and stirring rod while injecting a drilling stabilizing liquid, and then, for example, a foot-solidifying liquid, which is a hydraulic composition slurry, is injected into the excavated hole, and then the drilling and stirring rod is slowly pulled up while injecting a pile periphery fixing liquid, and then a precast concrete pile is lowered into the hole, or a method in which a pile periphery fixing liquid, which is a hydraulic composition slurry, is injected into the excavated hole, and then a foot-solidifying liquid is injected, and then a restrictive concrete pile is lowered.

[0003] Patent Document 1 discloses a hydraulic composition for pile construction, which contains (A) a sulfate ester or a salt thereof, in which the hydrocarbon group has 12 to 22 carbon atoms and the average number of added moles of alkylene oxide is 0 to 25, (B) a fatty acid alkanolamide in which the fatty acid moiety has 10 to 22 carbon atoms, a hydraulic powder, and water, and discloses that the hydraulic composition for pile construction has excellent water leakage prevention performance in a pile periphery fixing liquid used in a precast concrete pile embedding method, a cast-in-place pile method, a mortar column method, etc. Patent Document 2 discloses a thickener composition for hydraulic compositions, which contains (a) an alkylnaphthalenesulfonic acid having an alkyl group with two or more carbon atoms, or a salt thereof, and (b) one or more selected from amphoteric surfactants and cationic surfactants, and which increases the viscosity of the hydraulic composition slurry after preparation and increases the bleeding rate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-105124 [Patent Document 2] Japanese Patent Application Publication No. 2024-37207 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a method for manufacturing a base protection portion of a pile, which has excellent filling properties when manufacturing the base protection portion of a pile by injecting a hydraulic composition slurry into a borehole in a concrete pile embedding method. [Means for solving the problem]

[0006] The present invention relates to a method for manufacturing a base protection portion of a pile, in which a hydraulic composition slurry containing hydraulic powder, the following component (a), and water is injected into a borehole from the bottom of the borehole in a method for embedding a concrete pile: Component (a): one or more selected from amphoteric surfactants and cationic surfactants [Effects of the Invention]

[0007] According to the present invention, there is provided a method for manufacturing a base protection portion of a pile, which has excellent filling properties when manufacturing the base protection portion of a pile by injecting a hydraulic composition slurry into a borehole in a concrete pile embedding method. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a simulation evaluation device for evaluating the filling property in a borehole in an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The reason why the method for manufacturing a pile base protection portion of the present invention has excellent filling properties when injecting a hydraulic composition slurry into a borehole to manufacture a pile base protection portion in a concrete pile embedding method is not entirely clear, but is presumed to be as follows. For example, a hydraulic composition slurry composed of cement and water easily mixes with mud water. Therefore, when the hydraulic composition slurry is injected into a borehole containing mud water, it is difficult for the hydraulic composition slurry to remain entirely at the bottom of the borehole. On the other hand, in the hydraulic composition slurry containing component (a) of the present invention, component (a) forms string-like micelles in the water in the hydraulic composition slurry, imparting viscosity to the hydraulic composition slurry and ensuring underwater non-separation. Therefore, it is believed that the hydraulic composition slurry of the present invention tends to remain at the bottom of the borehole without mixing with the mud water. Furthermore, hydraulic composition slurries without component (a) have low elasticity, and when injected into mud water or soil cement in a borehole, they tend to escape to the top through gaps and flow areas, such as around the rod. However, the hydraulic composition slurry of the present invention containing component (a) can impart elastic viscosity not found in other general thickeners, giving the hydraulic composition slurry cohesion and allowing it to push up muddy water and soil cement without letting them escape through gaps, which is thought to result in excellent filling properties when manufacturing root protection sections. However, the present invention is not limited to the above-mentioned mechanism of action.

[0010] [Manufacturing method for the base of the pile] The hydraulic composition slurry used in the method for manufacturing a pile base protection portion of the present invention (hereinafter referred to as the hydraulic composition slurry of the present invention) contains hydraulic powder, the following component (a), and water. Component (a): one or more selected from amphoteric surfactants and cationic surfactants

[0011] The hydraulic composition slurry of the present invention contains, as component (a), one or more surfactants selected from (a1) amphoteric surfactants (hereinafter referred to as component (a1)) and (a2) cationic surfactants (hereinafter referred to as component (a2)). Component (a) is preferably one or more surfactants selected from amphoteric surfactants having a nitrogen atom and cationic surfactants having a nitrogen atom.

[0012] The amphoteric surfactant of the component (a1) is preferably an amine oxide surfactant, and more preferably a compound represented by the following general formula (a1).

[0013] [ka]

[0014] [Wherein X is R 11a or R 12a -[CONH-CH2CH2CH2] n R is a group represented by the formula 11a R is an alkyl group having 14 to 22 carbon atoms or an alkenyl group having 14 to 22 carbon atoms. 12a is an alkyl group having 13 to 21 carbon atoms or an alkenyl group having 13 to 21 carbon atoms. n is an integer of 1 to 3. 2 and R 3 are each independently an alkyl group having 1 to 4 carbon atoms or -(C2H4O) p H. p is the average number of moles added, and R 2 and R 3 The sum of these is a number between 0 and 5.

[0015] In the general formula (a1), X is R 11a or R 12a -[CONH-CH2CH2CH2] n - is a group represented by the formula: R 11a is an alkyl group having 14 to 22 carbon atoms or an alkenyl group having 14 to 22 carbon atoms. R 11aWhen is an alkenyl group, it preferably has 18 or more carbon atoms and preferably 22 or less carbon atoms. R 11a When is an alkyl group, it preferably has 16 or more carbon atoms and preferably has 22 or less carbon atoms. R 12a is an alkyl group having 13 to 21 carbon atoms or an alkenyl group having 13 to 21 carbon atoms. R 12a When is an alkenyl group, it preferably has 17 or more carbon atoms and preferably 21 or less carbon atoms. R 12a When is an alkyl group, it preferably has 15 or more carbon atoms and preferably has 21 or less carbon atoms. n is preferably 0 or 1. R 2 and R 3 are each independently preferably an alkyl group having 1 to 2 carbon atoms or -(C2H4O) p It is a group represented by H. p is preferably a number between 0 and 3.

[0016] Specific examples of the compound of component (a1) include one or more selected from oleyl dimethylamine oxide, oleic acid amidopropyl dimethylamine oxide, stearyl dimethylamine oxide, and palmityl dimethylamine oxide.

[0017] The cationic surfactant of component (a2) is preferably a quaternary ammonium surfactant, and more preferably at least one selected from the group consisting of compounds represented by the following general formula (a21) and compounds represented by the following general formula (a22):

[0018] [ka]

[0019] [In the formula, R 21a is an aliphatic hydrocarbon group having 8 to 22 carbon atoms, and R 22ais a group selected from an aliphatic hydrocarbon group having 8 to 22 carbon atoms, an alkyl group having 1 to 3 carbon atoms, and a hydroxyalkyl group having 1 to 3 carbon atoms, and R 23a and R 24a are each independently a group selected from an alkyl group having 1 to 3 carbon atoms and a hydroxyalkyl group having 1 to 3 carbon atoms, and X - is an anion.

[0020] [ka]

[0021] [In the formula, R 25a is an aliphatic hydrocarbon group having 8 to 22 carbon atoms, and R 26a and R 27a are each independently a group selected from an alkyl group having 1 to 3 carbon atoms and a hydroxyalkyl group having 1 to 3 carbon atoms, and X - is an anion.

[0022] In general formula (a21), R 21a The number of carbon atoms in R is 8 or more, preferably 10 or more, more preferably 14 or more, and even more preferably 16 or more, and is 22 or less, preferably 20 or less, and more preferably 18 or less, from the viewpoint of the balance between water solubility and high hydrophobicity that easily interacts with the component (b) described below. 21a is preferably an alkyl group or an alkenyl group, and is preferably an alkyl group. In general formula (a21), R 22a is a group selected from aliphatic hydrocarbon groups having 8 to 22 carbon atoms, alkyl groups having 1 to 3 carbon atoms, and hydroxyalkyl groups having 1 to 3 carbon atoms. R 22a is an aliphatic hydrocarbon group having 8 to 22 carbon atoms, R 22a is 8 or more, preferably 10 or more, more preferably 14 or more, even more preferably 16 or more, and 22 or less, preferably 20 or less, more preferably 18 or less, and is an alkyl group or an alkenyl group, preferably an alkyl group. R22a is preferably an alkyl group having 1 to 3 carbon atoms.

[0023] In general formula (a21), R 23a and R 24a are each independently a group selected from an alkyl group having 1 to 3 carbon atoms and a hydroxyalkyl group having 1 to 3 carbon atoms. 23a and R 24a are preferably each independently a group selected from alkyl groups having 1 to 3 carbon atoms. Examples of alkyl groups having 1 to 3 carbon atoms include a methyl group, an ethyl group, and a propyl group. Examples of hydroxyalkyl groups having 1 to 3 carbon atoms include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.

[0024] In general formula (a21), X - is an anion. Examples of anions include halogen ions such as chloride ions, bromide ions, and iodide ions. Examples of anions also include alkyl sulfate ions having 1 to 3 carbon atoms such as methyl sulfate ions, ethyl sulfate ions, and propyl sulfate ions.

[0025] Preferred examples of the compound of general formula (a21) include one or more selected from N-alkyl-N,N,N-trimethylammonium salts in which the alkyl group has 8 or more and 22 or less carbon atoms, N,N-dialkyl-N,N-dimethyl-ammonium salts in which the alkyl group has 8 or more and 22 or less carbon atoms, N,N-dialkyl-N-ethyl-N-methylammonium salts in which the alkyl group has 8 or more and 22 or less carbon atoms, and N-alkyl-N,N-dimethyl-N-ethylammonium salts in which the alkyl group has 8 or more and 22 or less carbon atoms. Specific examples of the compound of component (a21) include one or more selected from lauryltrimethylammonium salt, myristyltrimethylammonium salt, palmityltrimethylammonium salt, and stearyltrimethylammonium salt.

[0026] In general formula (a22), R 25ais an aliphatic hydrocarbon group having 8 to 22 carbon atoms. 25a The number of carbon atoms in R is 8 or more, preferably 12 or more, more preferably 14 or more, and even more preferably 16 or more, and is 22 or less, preferably 20 or less, and more preferably 18 or less, from the viewpoint of the balance between water solubility and high hydrophobicity that easily interacts with the component (b) described below. 25a is preferably an alkyl group or an alkenyl group, and is preferably an alkyl group.

[0027] In general formula (a22), R 26a and R 27a are each independently a group selected from an alkyl group having 1 to 3 carbon atoms and a hydroxyalkyl group having 1 to 3 carbon atoms. 26a and R 27a are preferably each independently a group selected from alkyl groups having 1 to 3 carbon atoms. Examples of alkyl groups having 1 to 3 carbon atoms include a methyl group, an ethyl group, and a propyl group. Examples of hydroxyalkyl groups having 1 to 3 carbon atoms include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.

[0028] In general formula (a22), X - is an anion. Examples of anions include halogen ions such as chloride ion, bromide ion, and iodide ion. Examples of anions also include alkyl sulfate ions having 1 to 3 carbon atoms such as methyl sulfate ion, ethyl sulfate ion, and propyl sulfate ion.

[0029] Specific examples of the compound of general formula (a22) include N-octyl-N,N-dimethyl-N-benzyl ammonium salt, N-decyl-N,N-dimethyl-N-benzyl ammonium salt, N-dodecyl-N,N-dimethyl-N-benzyl ammonium salt, N-tridecyl-N,N-dimethyl-N-benzyl ammonium salt, N-tetradecyl-N,N-dimethyl-N-benzyl ammonium salt, N-pentadecyl-N,N-dimethyl-N-benzyl ammonium salt, N-hexadecyl-N,N-dimethyl-N-benzyl ammonium salt, N-dodecyl-N,N-diethyl-N-benzyl ammonium salt, and N-tridecyl-N,N-diethyl-N-benzyl ammonium salt. and N-hexadecyl-N,N-diethyl-N-benzylammonium salt, N-dodecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-tridecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-tetradecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-pentadecyl-N,N-diethyl-N-benzylammonium salt, N-hexadecyl-N,N-diethyl-N-benzylammonium salt, N-dodecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-tridecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-tetradecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-pentadecyl-N-methyl-N-ethyl-N-benzylammonium salt, and N-hexadecyl-N-methyl-N-ethyl-N-benzylammonium salt.

[0030] From the viewpoint of the strength of the base of the pile, the hydraulic composition slurry of the present invention preferably contains, as component (b), an alkylnaphthalenesulfonic acid in which the alkyl group has two or more carbon atoms, or a salt thereof. From the viewpoint of the balance between hydrophobic interaction and water solubility, the number of carbon atoms in the alkyl group of the alkylnaphthalenesulfonic acid of component (b) is 2 or more, preferably 3 or more, and preferably 10 or less, more preferably 5 or less, and even more preferably 4. The position of the alkyl group on the naphthalene ring may be any position. From the viewpoint of packing properties, the number of alkyl group substituents in the alkylnaphthalenesulfonic acid of component (b) is preferably 1 or more and preferably 3 or less, more preferably 2 or less, and even more preferably 1. Furthermore, when the number of alkyl group substituents is 2 or more, it is sufficient that at least one of the alkyl groups has 2 or more carbon atoms. From the viewpoint of interaction with component (a), the number of sulfo group substituents in the alkylnaphthalenesulfonic acid of component (b) is preferably 1 or more and preferably 3 or less, more preferably 2 or less, and even more preferably 1. Furthermore, with regard to the position of the sulfo group on the naphthalene ring, it is preferable that at least one sulfo group is at the 1-position. The salt of alkylnaphthalenesulfonic acid of component (b) may be one or more selected from alkali metal salts such as sodium salts and potassium salts, and ammonium salts.

[0031] Specific examples of the compound of component (b) include one or more selected from butylnaphthalenesulfonic acid, ethylnaphthalenesulfonic acid, propylnaphthalenesulfonic acid, pentylnaphthalenesulfonic acid, hexylnaphthalenesulfonic acid, octylnaphthalenesulfonic acid, decylnaphthalenesulfonic acid, and salts thereof. From the viewpoint of the balance between hydrophobic interaction and water solubility, preferred is one or more selected from butylnaphthalenesulfonic acid, ethylnaphthalenesulfonic acid, propylnaphthalenesulfonic acid, pentylnaphthalenesulfonic acid, and salts thereof, more preferred is one or more selected from butylnaphthalenesulfonic acid, ethylnaphthalenesulfonic acid, propylnaphthalenesulfonic acid, and salts thereof, and even more preferred is butylnaphthalenesulfonic acid or a salt thereof.

[0032] The hydraulic composition slurry of the present invention contains hydraulic powder. The hydraulic powder is a powder that hardens when mixed with water, and examples thereof include ordinary Portland cement, high-early-strength Portland cement, ultra-high-early-strength Portland cement, sulfate-resistant Portland cement, low-heat Portland cement, white Portland cement, and ecocement (e.g., JIS R5214, etc.), and one or more of these can be used. Among these, from the viewpoint of shortening the time until the cement milk or the base protection portion of the pile reaches the required strength, the hydraulic powder is preferably one or more cements selected from early-early-strength Portland cement, ordinary Portland cement, sulfate-resistant Portland cement, and white Portland cement, and more preferably one or more cements selected from early-early-strength Portland cement and ordinary Portland cement.

[0033] The hydraulic powder may contain blast furnace slag, fly ash, silica fume, anhydrous gypsum, etc., or may contain non-hydraulic limestone fine powder, etc. The hydraulic powder may be one or more selected from blast furnace cement, fly ash cement, and silica fume cement, which are mixtures of cement with blast furnace slag, fly ash, silica fume, etc. Clay such as bentonite may also be included.

[0034] The hydraulic composition slurry contains water. The water that can be used may be tap water, river water, lake water, or the like.

[0035] In the hydraulic composition slurry of the present invention, the mass percentage of the water content to the hydraulic powder content (water / hydraulic powder ratio (W / P)) is preferably 45 mass% or more, more preferably 50 mass% or more, even more preferably 60 mass% or more, and is 150 mass% or less, preferably 120 mass% or less, even more preferably 100 mass% or less, and still more preferably 80 mass% or less, from the viewpoints of economy and fluidity of the hydraulic composition slurry. Here, the water / hydraulic powder ratio (W / P) is the mass percentage (mass%) of water to hydraulic powder in the hydraulic composition slurry, and is calculated as water / hydraulic powder x 100. The water / hydraulic powder ratio is calculated based on the amount of powder that has the physical property of hardening through a hydration reaction. Furthermore, when the hydraulic powder is cement, W / P may be expressed as W / C. In addition, when the hydraulic powder includes powders selected from powders with pozzolanic action, powders with latent hydraulic properties, and stone powder (calcium carbonate powder) in addition to powders such as cement that harden through hydration, the amounts of these powders are also included in the amount of hydraulic powder in this invention. Furthermore, when the powder that hardens through hydration contains a high-strength admixture, the amount of the high-strength admixture is also included in the amount of hydraulic powder. This also applies to other parts by mass that involve the mass of the hydraulic powder.

[0036] The hydraulic composition slurry of the present invention contains, per 100 parts by mass of hydraulic powder, preferably 0.01 part by mass or more of component (a) from the viewpoint of thickening the hydraulic composition slurry, more preferably 0.02 part by mass or more, even more preferably 0.05 part by mass or more, and still more preferably 0.08 part by mass or more, and from the viewpoint of economy and pumpability of the hydraulic composition slurry, preferably 2 parts by mass or less, more preferably 0.8 part by mass or less, even more preferably 0.5 part by mass or less, still more preferably 0.3 part by mass or less, still more preferably 0.2 part by mass or less, and still more preferably 0.15 part by mass or less. In the present invention, when component (a2) is contained as component (a), the mass of component (a2) is the value obtained by converting component (a2) into a chlorine salt.

[0037] When the hydraulic composition slurry of the present invention contains component (b), the hydraulic composition slurry contains component (b) in an amount, per 100 parts by mass of hydraulic powder, of preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, even more preferably 0.015 part by mass or more, and still more preferably 0.02 part by mass or more, from the viewpoint of thickening the hydraulic composition slurry, and from the viewpoint of economy and preventing bleeding, preferably 4 parts by mass or less, more preferably 2 parts by mass or less, even more preferably 1 part by mass or less, still more preferably 0.5 parts by mass or less, still more preferably 0.1 part by mass or less, and still more preferably 0.08 part by mass or less. In the present invention, the mass of component (a) is expressed as the value of component (a) converted into the sodium salt.

[0038] In the hydraulic composition slurry of the present invention, the mass ratio (b) / (a) of the content of the component (b) to the content of the component (a) is preferably 0.15 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and is preferably 2 or less, more preferably 1.5 or less, even more preferably 0.8 or less, and still more preferably 0.6 or less, from the viewpoint of adjusting the packing parameter that keeps the micelle shape in a string or rod shape and thereby increasing the bleeding rate and thickening property of the hydraulic composition slurry.

[0039] The hydraulic composition slurry of the present invention may further contain an antifoaming agent as component (c) from the viewpoint of the strength of the root protection portion. The antifoaming agent is preferably one or more selected from silicone-based antifoaming agents, fatty acid ester-based antifoaming agents, ether-based antifoaming agents, and aliphatic amine-based antifoaming agents, and more preferably silicone-based antifoaming agents. Among silicone-based antifoaming agents, dimethylpolysiloxane is more preferred, among fatty acid ester-based antifoaming agents, polyalkylene glycol fatty acid ester is more preferred, among ether-based antifoaming agents, polyalkylene glycol alkyl ether is more preferred, and among aliphatic amine-based antifoaming agents, alkyldimethylamine or its salt is more preferred.

[0040] When the hydraulic composition slurry of the present invention contains the component (b) and the component (c), the mass ratio (c) / [(a)+(b)] of the content of the component (c) to the total content of the components (a) and (b) in the hydraulic composition slurry is, from the viewpoints of defoaming property, economy, and not impairing performance, preferably 0.00001 or more, more preferably 0.0001 or more, even more preferably 0.001 or more, still more preferably 0.001 or more, still more preferably 0.05 or more, and preferably 10 or less, more preferably 5 or less, even more preferably 1 or less, and still more preferably 0.5 or less.

[0041] The hydraulic composition slurry of the present invention may further contain other components in addition to the above components, provided that the effects of the present invention are not affected, such as dispersants, air-entraining agents, retarders, foaming agents, thickeners, foaming agents, waterproofing agents, and fluidizing agents (excluding the hydraulic powder and components (a) to (c)).

[0042] In the method for manufacturing a pile base protection portion of the present invention, the hydraulic composition slurry of the present invention is injected into a borehole from the bottom of the borehole in a concrete pile embedding method.

[0043] The borehole is formed by drilling the ground to the bearing layer using a drilling and stirring rod. Examples of drilling and stirring rods include drills, BW excavators, bucket-type hydrofraises, and electromills. The excavation of the ground using the drilling and stirring rod may be performed while injecting drilling fluid containing water, in which case mud containing soil and water is prepared in the borehole.

[0044] The drilling fluid contains water, and the water may be tap water, river water, lake water, or the like.

[0045] The drilling fluid may further contain a water-swellable clay. In the present invention, "water swelling" refers to the swelling volume (cm) of 2 g of clay mineral, measured according to the bentonite testing method prescribed in the 15th edition of the Japanese Pharmacopoeia. 3 ) is expressed as 10cm 3 / g or more. Examples of water-swellable clays include smectite clay minerals such as bentonite (including natural or synthetic bentonite), montmorillonite (including natural or synthetic montmorillonite), beidellite, nontronite, laponite, sauconite, hectorite (including natural or synthetic hectorite), stevensite, vermiculite, swellable synthetic fluorine mica (Na-type, Li-type synthetic mica), and swellable mica, and these can be used alone or in combination. From the standpoint of economic efficiency and availability, the water-swellable clay is preferably one or more selected from bentonite, montmorillonite, beidellite, nontronite, laponite, and hectorite, more preferably one or more selected from bentonite, montmorillonite, and hectorite, and even more preferably bentonite.

[0046] The water-swelling clay can be a commercially available clay used for construction and civil engineering foundation work. When bentonite is used as the water-swelling clay, bentonite with a high montmorillonite content is preferred, and bentonite with a high Na-montmorillonite content, which has high hydration and water swelling properties, is more preferred. Examples of bentonite include Kunigel GS, Kunigel V1, and Kunigel MB manufactured by Kunimine Kogyo Co., Ltd., and Super Clay, Neoclay, and Neomud manufactured by Hojun Co., Ltd.

[0047] By including water-swellable clay in the drilling fluid, it is possible to excavate the ground while preventing the collapse of the inner wall surface of the excavated hole. The amount of the drilling fluid to be injected into the ground may be determined appropriately taking into consideration the properties and conditions of the ground, etc. The specific method for filling the ground with the drilling fluid is not particularly limited, and can be carried out in accordance with known methods for injecting drilling fluid into the ground.

[0048] By injecting the drilling fluid into the borehole while drilling, a mud containing soil and water is prepared. The soil is generated by excavating the ground, and examples of the soil include gravel, sand, silt, clay, etc. When the drilling fluid contains the water-swellable clay, the mud may contain the water-swellable clay in addition to the clay contained in the soil. Therefore, in the method for manufacturing the base protection portion of a pile of the present invention, when the mud water is present in the borehole, the hydraulic composition slurry of the present invention is injected into the mud water present in the borehole.

[0049] In the present invention, injecting the hydraulic composition slurry of the present invention from the bottom of the borehole means providing an injection port at a position where the ratio of the distance from the bottom (bottom surface) of the borehole to the injection port where the hydraulic composition slurry is injected in the vertical direction to the target injection height of the borehole [distance from the bottom to the injection port / target injection height] is 0.2 or less, and injecting the hydraulic composition slurry of the present invention from the injection port into the borehole. The target injection height of the borehole refers to the vertical height from the bottom of the borehole of the base protection portion when the hydraulic composition slurry is injected into the borehole, filled from the bottom of the borehole, and hardened. Furthermore, when the hydraulic composition slurry is injected into the mud water present in the borehole, the target injection height of the borehole refers to the vertical height from the bottom of the borehole of the foot protection portion when the hydraulic composition slurry is injected into the borehole, the hydraulic composition slurry pushes up the mud water from the bottom of the borehole, filling it by completely replacing it, and hardens. The injection section is preferably installed such that the terminal opening of a pipe for injecting the hydraulic composition slurry of the present invention into the borehole from outside the borehole is positioned such that the ratio of the distance from the bottom (bottom surface) of the borehole to the injection section for injecting the hydraulic composition slurry in the vertical direction to the target injection height of the borehole [(distance from the bottom to the injection section) / target injection height] is 0.2 or less. For example, it is preferably installed at the tip or side of the head of a drilling and stirring rod. The pipe may pass through the inside or outside of the drilling and stirring rod, and is preferably flexible so as to be able to transport the hydraulic composition slurry, and examples of the material include elastomer, silicone, urethane, etc. Furthermore, when the pipe passes through the inside of the drilling and stirring rod, the pipe portion passing through the inside may be made of metal. Furthermore, an alkali-resistant material is preferred so as to prevent corrosion by the hydraulic composition slurry, and examples of materials such as metal, elastomer, silicone, urethane, etc. are preferred.

[0050] The ratio of the distance from the bottom (bottom surface) of the borehole to the injection point where the hydraulic composition slurry is injected vertically to the target injection height of the borehole [distance from the bottom to the injection point / target injection height] is preferably 0.2 or less, more preferably 0.1 or less, even more preferably 0.05 or less, and is preferably 0.001 or more, more preferably 0.005 or more, even more preferably 0.01 or more, from the viewpoint of filling the bottom.

[0051] From the viewpoint of bearing capacity, the ratio of the target injection height to the inner diameter of the borehole (target injection height / inner diameter) is preferably 0.6 or more, more preferably 1.0 or more, even more preferably 3 or more, and preferably 17 or less, more preferably 10 or less, even more preferably 7 or less, even more preferably 4 or less. The inner diameter of the borehole is approximately the same size (or slightly larger) as the rotation diameter of the head of the drilling and stirring rod used when drilling the ground, and may be the inner diameter at any position vertically from the bottom (bottom surface) of the borehole.

[0052] The hydraulic composition slurry of the present invention is injected into the excavated hole to produce the base protection portion of the pile. Furthermore, when mud water is present in the borehole, the hydraulic composition slurry of the present invention is injected into the mud water present in the borehole, and the hydraulic composition slurry pushes the mud water up from the bottom of the borehole, thereby replacing the mud water, and the hydraulic composition slurry hardens to produce a base reinforcement portion for the pile. When the mud water is present in the borehole, the hydraulic composition slurry of the present invention is injected and mixed so that the volume ratio of the amount of the hydraulic composition slurry of the present invention mixed to the amount of the mud water mixed (mud water / hydraulic composition slurry) is preferably 0.001 or more, more preferably 0.01 or more, even more preferably 0.1 or more, and preferably 2 or less, more preferably 1 or less, even more preferably 0.4 or less, and even more preferably 0.2 or less, from the viewpoint of the strength of the root protection portion.

[0053] After the base protection portion of the pile is manufactured in the excavation hole using the manufacturing method of the present invention, a concrete pile is sunk into the base protection portion of the pile in the excavation hole, and the base protection portion is hardened to integrate the ground and the pile. [Example]

[0054] [Ingredients used] The components used in the examples and comparative examples are shown below. <Component (a)> a-1: oleyldimethylamine oxide, component (a1), in which X is R 11a and R 11a is an alkenyl group having 18 carbon atoms, R 2 and R 3 is a methyl group a-2: oleic acid amide propyl dimethylamine oxide, component (a1), in which X is R 12a -[CONH-CH2CH2CH2] n - and R 12a is an alkenyl group having 18 carbon atoms, n is 1, and R 2 and R 3 is a methyl group <(b) Component> b-1: Sodium butylnaphthalene sulfonate, Pelex NBL, manufactured by Kao Corporation <(c) component> c-1: Asahi Silicone AF-146, a silicone-based defoamer, manufactured by Asahi Chemical Industry Co., Ltd.

[0055] [Filling evaluation using a simulation evaluation device] [Mud preparation] Simulated muddy water was prepared by mixing sand, clay, and water. Mountain sand (density 2.6, manufactured by Joyo) was used as the sand, and Tochi clay (density 2.65, manufactured by Ohtake Kogyo Co., Ltd.) was used as the clay. The muddy water was prepared by mixing mountain sand, Tochi clay, and water according to the composition shown in Table 1. The specific gravity of the prepared muddy water was the value shown in Table 1. The specific gravity was measured using a mud balance (S-252a, manufactured by Nishinippon Testing Instruments Co., Ltd.).

[0056] [Table 1]

[0057] [Preparation of hydraulic composition slurry] Each hydraulic composition slurry was prepared by adding hydraulic powder (C) (ordinary Portland cement (cement manufactured by Sumitomo Osaka Cement Co., Ltd.: cement manufactured by Taiheiyo Cement Corporation = 1:1 (weight ratio)), water (W), component (a), component (b), and component (c) to a 2-liter cup and mixing with a cooking hand mixer for 1 minute so as to obtain the respective contents shown in Table 2. W / C (mass%) is the mass percentage (water / hydraulic powder) of the water content and the hydraulic powder content in each hydraulic composition slurry.

[0058] [Filling evaluation using a simulation evaluation device] To evaluate the filling ability in the borehole, a simulated evaluation device (Fig. 1) was created that mimics a borehole with an inner diameter of 50 mm and a depth of 400 mm. The resin cylinder (cylinder inner diameter 44 mm, height 300 mm) shown in Figure 1 was fixed with a clamp (omitted in Figure 1), and the prepared mud water shown in Table 1 was poured into a breathing bag (polyethylene bag for measuring PC grout bleeding rate, manufactured by the Japan Society of Civil Engineers) to a height of 200 mm (approximately 400 mL), and the breathing bag containing the mud water was attached to the bottom end of the resin cylinder as shown in Figure 1. Next, a rubber hose with a diameter of 2 to 3 mm was attached to a metal rod, and the metal rod was fixed with a clamp (not shown in Figure 1) so that the end opening of the rubber hose attached to the metal rod was positioned 2 to 5 mm vertically from the bottom (bottom surface) so as not to touch the bottom of the breathing bag in Comparative Example 1 and Examples 1 and 2, and in Comparative Example 2, the metal rod was fixed with a clamp so that the end opening was positioned 2 to 5 mm above the surface of the muddy water (i.e., 202 to 205 mm vertically from the bottom of the breathing bag), as shown in Figure 1. In Example 3, the metal rod was fixed with a clamp (not shown in Figure 1) so that the end opening was positioned 40 mm vertically from the bottom, and the rubber hose was fixed with tape to the metal rod so that the injection direction of the end opening was downward. A 500 ml syringe was attached to the rubber hose on the side opposite the breathing bag, and each hydraulic composition slurry listed in Table 2 was slowly injected immediately after preparation. When the interface between the mud water and hydraulic composition slurry injected into the breathing bag and the air reached a height of 400 mm from the bottom of the breathing bag (injection amount of hydraulic composition slurry: approximately 400 ml, target injection height: 200 mm), the metal rod and rubber hose were removed, and the foot protection area was left to stand for 24 hours until it hardened. Here, the target injection height refers to the vertical height of the foot protection area from the bottom of the borehole (breathing bag) when the hydraulic composition slurry is injected into the borehole (breathing bag), the hydraulic composition slurry pushes up from the bottom of the borehole (breathing bag), filling it by completely displacing the mud water, and then hardening. For each example and comparative example, the ratio of the distance from the bottom of the breathing bag to the injection part where each hydraulic composition slurry is injected in the vertical direction to the target injection height of the breathing bag [(distance from the bottom to the injection part) / target injection height] is shown in Table 2. The inner diameter of the breathing bag was 50 mm, the depth was 400 mm, and the target injection height / inner diameter was 4. For each example and comparative example, the hardened root protection section was removed from the breathing bag and its filling property was evaluated. The breathing bag was removed from the hardened root protection section, lightly rinsed, and the height of the root protection section was measured. When 400 ml of hydraulic composition slurry was filled into the breathing bag, the height was approximately 200 mm. Therefore, if the hydraulic composition slurry pushed up the muddy water from the bottom of the breathing bag and was injected with complete displacement, the target injection height of the hardened root protection section was 200 mm. In other words, the closer the height ratio calculated as "root protection section height (mm) / 200 mm (target injection height) = height ratio" is to 1, the more complete the displacement and the better the filling property can be determined. Furthermore, if the bottom of the hardened root protection section did not harden according to the shape of the bag and there were unfilled areas, this was deemed "there was an unfilled area at the bottom," and the filling property was determined to be poor. The results of the height ratio of filling ability and the presence or absence of chipping at the bottom are shown in Table 1. The pass / fail of filling ability was judged as "Good" if the height ratio was 1.2 or less and there was no chipping at the bottom, and "Poor" if the height ratio was over 1.2 and there was chipping at the bottom. The results are shown in Table 2. The strength of the hardened base was also measured. The strength was measured by curing and preparing specimens in accordance with the "Compression Strength Test Method for Foot Hardening Liquid and Pile Circumference Fixing Liquid Used in Embedding Method" of the Concrete Pile Construction Technology Association. The strength was measured after 7 days. The results are shown in Table 2.

[0059] [Table 2]

Claims

1. A method for manufacturing a base protection portion of a concrete pile, comprising injecting a hydraulic composition slurry containing hydraulic powder, the following component (a), and water into a borehole from the bottom of the borehole in a concrete pile embedding method: Component (a): one or more selected from amphoteric surfactants and cationic surfactants

2. The method for manufacturing a base protection portion of a pile according to claim 1 , wherein the hydraulic composition slurry contains the following component (b): Component (b): Alkylnaphthalenesulfonic acid with an alkyl group having two or more carbon atoms, or a salt thereof

3. 3. The method for manufacturing a base protection portion of a pile according to claim 1, wherein the hydraulic composition slurry is injected into mud water present in the borehole.

4. 3. The method for manufacturing a pile root protection portion according to claim 1, wherein the ratio of the distance from the bottom of the borehole to the injection point where the hydraulic composition slurry is injected vertically to the target injection height of the borehole [distance from the bottom to the injection point / target injection height] is 0.2 or less.

5. The method for manufacturing a pile base protection portion according to claim 1 or 2, wherein the ratio of the target injection height to the inner diameter of the borehole (target injection height / inner diameter) is 3 or more.

6. 3. The method for manufacturing a pile root protection portion according to claim 1 or 2, wherein the hydraulic composition slurry is injected by installing an injection section of a pipe for injecting the hydraulic composition slurry into the borehole from outside the borehole so that the end opening of the pipe is positioned 5 cm to 100 cm vertically from the bottom (bottom surface) of the borehole.

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