JP2019094414A - Hardening material composition for soil improvement and establishment method of soil improvement body - Google Patents

Abstract

To provide a hardening material composition capable of suitably using in a high-pressure injection mixing method and capable of establishing a soil improvement body having high tensile strength, and a method of establishing the soil improvement body using the solidification composition.SOLUTION: A hardening material composition including 0.01 wt.% or higher and 1.0 wt.% or lower of a nonionic polymer surfactant having an aromatic ring on a side chain and 50 wt.% or higher and 140 wt.% or lower of water relative to 100 pts.wt. of dry ash containing cement. The hardening material composition may further contain 0.4 wt.% or higher and 20 wt.% or lower of a carbon fiber.SELECTED DRAWING: None

Description

  The present invention relates to a solidifying material composition used in ground improvement work and a method of creating a ground improvement body using the same.

  Solidification material such as cement milk as a ground improvement method for stabilizing the ground, such as hardening the ground, increasing the strength, reducing the permeability, etc., in order to prevent the ground from falling in soft ground improvement work The high-pressure injection and agitation method is adopted, in which high-pressure injection is carried out deep in the ground, and agitation and mixing with soil are carried out. This method is also called jet grout method, and by inserting multiple tubes in the ground and rotating the tubes, high-pressure injection of solidified material into the ground from near the tip of these tubes is carried out by stirring and mixing with the soil of the ground, A ground improvement body is created in the ground to stabilize the ground.

  A solidifying material composition containing an additive has been proposed as a solidifying material to be injected at high pressure into the ground. For example, in Patent Document 1, an additive comprising sodium lignin sulfonate, an alkali metal carbonate, a block copolymer of polyethylene glycol and polypropylene glycol, and porous silica powder with respect to 100 parts by mass of a powdery cement-based solidifying material There is disclosed a solidifying material composition which contains 0.5 to 15 parts by mass of the solidifying material, the fluidity of the slime to be produced, and the early strength to be exhibited by the cured solid of the slime.

  Moreover, since the conventional ground improvement body is a mixture of the in-situ soil and the solidifying material, it can generally improve the compressive strength and shear strength of the soft underlying ground, but the presence or strength of the unimproved portion Due to the variation, almost no improvement in tensile strength can be expected. Therefore, a method has been proposed to form a ground improvement body in which fibers are mixed in addition to the in-situ soil and the solidifying material, but in the high pressure jet agitation method, high pressure (several 10MPa) It has been pointed out that it is difficult to inject the fiber material into the ground in a state of being mixed with the solidifying material using the nozzle to inject the solidifying material, and as a solution, it is necessary to There have been proposed a method of feeding a fiber material into a pressure region through separate piping (Patent Document 2), a method of pressing in fibers and then injecting a solid material at high pressure (Patent Document 3), and the like.

JP, 2009-286655, A Japanese Patent Application Laid-Open No. 2002-155528 JP, 2014-62365, A

  An object of the present invention is a solidifying material composition which can be used for a high pressure jet agitation method and can create a ground improvement body having high tensile strength, and a method of forming a ground improvement body using the solidifying material composition It is to provide.

  As a result of research conducted to solve the above-mentioned problems, the present inventors have found that a non-aromatic ring having an aromatic ring in a side chain of 0.01 to 1.0 parts by weight with respect to 100 parts by weight of dry ash containing cement. A solidifying material composition containing an ionic polymer surfactant and water in an amount of 50 parts by weight to 140 parts by weight is suitable for the high pressure jet agitation method, and the tensile strength of a cured product formed using the solidifying material composition Found out that they are superior, and completed the invention.

  The polymer surfactant is preferably a random copolymer of alkylene oxide and phenyl glycidyl ether, and more preferably a random copolymer of ethylene oxide, propylene oxide and phenyl glycidyl ether. In addition, the polymer surfactant preferably has a weight average molecular weight of 50,000 or more and 150,000 or less. The solidifying material composition may further contain 0.4 parts by weight or more and 20 parts by weight or less of carbon fibers.

  According to the present invention, 50 parts by weight of a nonionic polymeric surfactant having an aromatic ring in a side chain of 0.01 parts by weight or more and 1.0 parts by weight or less with respect to 100 parts by weight of dry ash containing cement By being a solidifying material composition containing 140 parts by weight or less of water, it is possible to obtain a solidifying material composition which is excellent in fluidity and suitable for a high pressure jet agitation method. Moreover, a ground improvement body with high tensile strength can be created by using the said solidification material composition for ground improvement.

  The solidifying material composition of the present invention comprises a nonionic polymer surfactant having an aromatic ring in the side chain. The above-mentioned high molecular weight surfactant is a branched polymer containing a main chain and a side chain, and the side chain has an aromatic ring. The structure of the side chain is not particularly limited as long as it has an aromatic ring, since the strength of the ground improvement body created from the solidified material composition of the present invention is improved. The action mechanism of strength improvement of the ground improvement body is not clear, but various alkali metal salts and metals, which are components of cement, are the electron rich π electron system of the aromatic ring possessed by the side chain of the above-mentioned polymeric surfactant. It is assumed that it interacts with the oxide and functions as a binder. Further, the structure of the main chain of the branched polymer constituting the above-mentioned polymer surfactant is not particularly limited as long as the above-mentioned polymer surfactant can function as a nonionic surfactant, Although any of ester type, ether type, ester / ether type or amide type may be used, it is preferable that it is an ether type main chain having a repeating unit of alkylene oxide.

  Specifically, the polymer surfactant is preferably a random copolymer of alkylene oxide and phenyl glycidyl ether. In particular, a random copolymer of ethylene oxide and phenyl glycidyl ether, or a random copolymer of ethylene oxide and propylene oxide and phenyl glycidyl ether is preferable. More specifically, the above-mentioned polymer surfactant is based on phenyl glycidyl ether (PGE), ethylene oxide (EO) and propylene oxide (PO), and has the following chemical formula:

[Wherein, l and n are integers of 1 or more, m is an integer of 0 or more, and the arrangement order of PGE, EO and PO is random. ]
It is preferable to have a structural unit represented by

  l is an integer of 1 or more, and m is an integer of 0 or more. n is an integer of 1 or more, preferably 60 or more, and particularly preferably 150 or more.

  The copolymerization ratio (mass ratio) EO: PGE of ethylene oxide and phenyl glycidyl ether is preferably 70:30 to 99.5: 0.5, more preferably 80:20 to 99.5: 0.5, particularly preferably Is 80:20 to 99: 1. When propylene oxide is contained, the copolymerization ratio (mass ratio) is preferably 30 or less, more preferably 20 or less, and particularly preferably 10 or less.

  When the copolymerization ratio of the polymer surfactant is in the above range, the improvement effect of the tensile strength in the ground improvement body formed using the solidified material composition of the present invention containing the polymer surfactant is favorable. It is easy to be exhibited.

  The weight average molecular weight Mw of the polymer surfactant is preferably larger from the viewpoint of improving the tensile strength of the ground improvement body formed from the solidified material composition of the present invention, but if it is too large, the high pressure injection of the solidified material composition Will be difficult. The range of the weight average molecular weight Mw is preferably 4,000 to 10,000,000, more preferably 4,000 to 1,000,000, and particularly preferably 5,000 to 150,000.

The weight average molecular weight Mw can be measured, for example, using gel permeation chromatography (GPC) under the following measurement conditions.
<Measurement conditions>
Device: Product name "LC-10AD" (made by Shimadzu Corporation)
Detector: Differential Refractive Index Detector (RID)
Column: Product name "SHODEX KF-804" (manufactured by Showa Denko KK)
Measurement temperature: 30 ° C
Eluent: THF
Flow rate: 1.0 mL / min
Sample concentration: 0.2 mass% (THF)
Sample injection volume: 100 μL
Conversion standard: polyethylene oxide The molecular weight distribution (weight-average molecular weight Mw / number-average molecular weight Mn) of the above-mentioned polymer surfactant is not particularly limited, but preferably 5 or less, more preferably 3 or less, particularly preferably 2 or less . The number average molecular weight Mn can be measured using gel permeation chromatography (GPC) in the same manner as the measurement of the weight average molecular weight Mw described above. When the molecular weight distribution of the polymeric surfactant is in the above range, for example, the solidified material composition containing the polymeric surfactant can have a viscosity suitable for high-pressure injection, and from the solidified material composition The improvement effect of the tensile strength in the formed ground improvement body tends to be favorably brought about.

  The degree of randomness of the polymeric surfactant is not particularly limited.

  The solidifying material composition of the present invention is a composition comprising a specific amount ratio of a nonionic polymer surfactant having an aromatic ring in a side chain and water to the weight of dry ash containing a hardening material such as cement. .

  The content of the polymer surfactant is 0.01 parts by weight or more and 1.0 parts by weight or less, preferably 0.03 parts by weight or more, 0.9 parts by weight with respect to 100 parts by weight of the dry ash content of the solidifying material composition. It is the weight part or less, more preferably 0.05 weight part or more and 0.7 weight part or less. The term "dry ash" as used herein includes hardened materials such as cement and other solid aggregate filler materials, and does not include the above-mentioned polymeric surfactant and carbon fibers described later.

  When the content of the polymer surfactant is small, the effect of improving the tensile strength to the ground improvement body using the solidified material composition of the present invention is low, and particularly the tensile strength is improved when it is less than 0.01 parts by weight I can not see the effect of On the other hand, when the content of the polyalkylene oxide is too large, the viscosity of the solidifying material composition of the present invention becomes high and high pressure injection becomes difficult, and when it exceeds 1.0 parts by weight, high pressure injection becomes impossible.

  The solidifier composition of the present invention comprises water to form a slurry. The content of water is 50 parts by weight or more and 140 parts by weight or less, preferably 60 parts by weight or more and 130 parts by weight or less, more preferably 70 parts by weight or more and 120 parts by weight per 100 parts by weight dry ash of the solidifying material composition. It is below a weight part. When the content of water in the solidifying material composition is small, the viscosity of the solidifying material composition becomes high, so clogging in the pumping line is likely to occur, and high-pressure injection becomes difficult. In particular, when the amount is less than 50 parts by weight, high pressure injection becomes impossible. On the other hand, when the water content is high, it takes time to cure the solidifying material composition, so that the expression of the initial strength of the construction of the ground improvement body becomes insufficient. In addition, the low viscosity of the solidifying material composition makes it easy for the solidifying material composition to run away, and it may not be possible to create a ground improvement body suitably.

  Hardeners included in the solidified material composition of the present invention include 1) various portland cements such as ordinary cement, early-strength cement, ultra-early-strength cement, medium heat cement, 2) blast furnace cement, fly ash cement, silica cement, etc. The various mixed cements of this, etc. are mentioned, These 1 type (s) or 2 or more types can be used suitably. Among them, as a powdery cement-based solidifying material, various portland cements and fine powder blends of blast furnace slag fine powder, fly ash, silica fume fine powder, limestone fine powder, gypsum and the like within the range of 70% by mass or less thereof A mixture of the material and the material is preferable, and it is composed of ordinary portland cement and blast furnace cement type B, and 10 to 40% by mass of ordinary portland cement and 60 to 90 mass% of blast furnace cement type B (total 100% by mass). What contains is more preferable.

  The solidifying material composition of the present invention preferably further contains carbon fiber. The content of the carbon fiber is preferably 0.4 parts by weight or more and 20 parts by weight and particularly preferably 0.5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the dry ash content of the solidifying material composition. Examples of the carbon fiber include, for example, polyacrylonitrile-based (PAN-based) carbon fiber, pitch-based carbon fiber, or kynol carbon fiber, or rayon-based carbon fiber. Among these, carbon fibers using mesophase pitch as a spinning material are suitably used. As this mesophase pitch carbon fiber, carbon fibers from conventionally known mesophase pitch such as coal-based, petroleum-based or synthetic pitch-based can be used. When the solidifying material composition of the present invention optionally contains the above-mentioned carbon fiber, the constructed ground improvement body exhibits further excellent tensile strength.

  The carbon fibers optionally contained in the solidifying material composition of the present invention are carbon fibers having an average fiber diameter of 3 to 20 μm, preferably 5 to 18 μm. If the fiber diameter of the carbon fiber exceeds 20 μm, the ratio L / D, which is the ratio of the fiber length to the fiber diameter, tends to generally decrease, so that the tensile strength improvement effect to the ground improvement body can not be sufficiently obtained. If the fiber diameter is too small, it tends to be difficult to uniformly disperse in the solidifying material composition. The carbon fiber has a length of about 1 to 10 mm, preferably 2 to 7 mm. If the fiber length of the carbon fiber is too long, the nozzle may be clogged during high pressure injection of the solidifying material composition, and if it is too short, the tensile strength improvement effect of the ground improvement body formed from the solidifying material composition is sufficiently obtained Absent. The ratio of fiber length to fiber diameter (L / D) is preferably 100 or more. When L / D is too small, the tensile strength improvement effect to a ground improvement body is not fully acquired. The fibers may be dispersed one by one or collected by a bundling agent, and may be selected arbitrarily.

  In the solidifying material composition of the present invention, any aggregate, filler, water reducing agent, thickening agent, flowability adjusting agent, antifoaming agent, preservative, delayed setting, as long as the effects of the present invention are not impaired. Agents, setting accelerators and the like can be included.

  The solidifying material composition of the present invention described above can be manufactured by a known method. For example, after the above-mentioned carbon fiber is optionally added and mixed to the above-mentioned polymer surfactant aqueous solution, the above-mentioned hardening agent such as cement is added and kneaded.

  In addition, the solidifying material composition of the present invention is useful for various ground improvement works, in particular, a high pressure jet agitation method. In the high-pressure jet stirring method, a hole of about 15 cm in diameter is drilled from the ground to the ground (30 m to 50 m), and the solidifying material composition for cutting is pumped and supplied at ultrahigh pressure (5 to 50 MPa) through the supply pipe into the hole. , The surrounding ground is cut by jet jet from the nozzle installed at the tip. While discharging the cut earth and sand on the ground, a columnar ground improvement body is created in the ground by stirring and mixing with the hardening solidifying material composition to be jetted next. The solidifying material composition for cutting and the solidifying material composition for curing may have the same composition or different compositions. The solidifying material composition of the present invention is preferably used as a solidifying material composition for curing, since it can form a ground improvement body having excellent tensile strength.

  Furthermore, the solidifying material composition containing the carbon fiber of the present invention is characterized by having high dispersibility of the carbon fiber in the composition since it contains the above-mentioned polymer surfactant. The high dispersibility of the carbon fiber makes it easy to develop strength when made into a ground improvement body, and since the nozzle is not clogged when injecting the solidifying material composition to the ground, a single supply is possible. Pumping to the ground by a pipe is possible.

  Hereinafter, the present invention will be further described by way of examples, but the present invention is not limited to these examples.

Example 1
Into a stirring bowl are charged 5.6 kg of water and 70 g of an AE water reducing agent ("POZOLIS No. 8" manufactured by BASF Corp.) diluted fourfold with water, and then a polymeric surfactant ("Alcox CP-" manufactured by Meisei Chemical Co., Ltd.) 3.78 g of B2 (a random copolymer of ethylene oxide, propylene oxide and phenyl glycidyl ether) was added, and a stirrer ("Mighty S20" manufactured by Aikosha Co., Ltd., using a beater type as a stirring blade) was added 60 Stirred for a second. Further, several drops of an antifoaming agent ("foamless" manufactured by Meisei Chemical Industry Co., Ltd.) and 63 g of carbon fiber ("KCF- 100 C-103S" manufactured by Kureha) were added, and stirred for 150 seconds. It was visually confirmed that the carbon fibers were not agglomerated and dispersed, and after pouring Portland cement little by little, it was stirred for 90 seconds. The contents were transferred from the stirring bowl to another container, and the precipitate remaining on the bottom of the bowl was crushed with a spatula, and then the content was returned from the other container to the bowl and stirred for another 90 seconds to give a solidified material composition.

The above solidifying material composition is packed in a metallic test specimen type (diameter 100 mm, height 200 mm), a glass plate is placed on the upper part of a mold, and after curing for 1 week at 20 ° C. in a thermostatic chamber I got a sample. The split tensile strength (JIS A 1113: 2006) of this sample was measured using a fully automatic compression tester (Hi-ACTIS-2000 (2000 N) manufactured by Marui). The split tensile strength at break was 1.55 N / mm ² .

Comparative Example 1
Into a stirring bowl, 5.6 kg of water and 70 g of an AE water reducing agent ("Pozzolith No. 8" manufactured by BASF Corp.) diluted by 4 times with water were added, and after gradually adding Portland cement, using the same stirrer as in Example 1. Stir for 90 seconds. The contents were transferred from the stirring bowl to another container, and the precipitate remaining on the bottom of the bowl was crushed with a spatula, and then the content was returned from the other container to the bowl and stirred for another 90 seconds to give a solidified material composition.

The split tensile breaking strength of the test piece measured in the same manner as in Example 1 using this solidified material composition was 0.90 N / mm ² .

[Reference Example 1]
A specimen was obtained in the same manner as in Example 1 except that 3.78 g of polyether type polyurethane ("Palset HA" manufactured by Meisei Chemical Co., Ltd.) was added in addition to the polymeric surfactant. The split tensile strength at break of this sample was 1.50 N / mm ² .

  The present invention provides a solidified material composition capable of forming a ground improvement body having high tensile strength in a high pressure jet agitation method, and can provide a method of forming a ground improvement body using the solidified material composition. It has industrial applicability.

Claims (7)

A composition comprising cement,
0.01 to 1.0 parts by weight of a non-ionic polymer surfactant having an aromatic ring in a side chain and 50 to 140 parts by weight of water with respect to 100 parts by weight of dry ash Solidifying material composition for high pressure jet agitation method including.   The solidifying material composition for high-pressure jet agitation method according to claim 1, further comprising carbon fiber of 0.4 parts by weight or more and 20 parts by weight or less.   The high-pressure jet agitation method according to claim 1 or 2, wherein the high molecular weight surfactant is a random copolymer of alkylene oxide and phenyl glycidyl ether, and the weight average molecular weight thereof is 50,000 or more and 150,000 or less. Solidifying agent composition.   The solidifying material composition for high pressure jet agitation method according to claim 3, wherein the high molecular weight surfactant is a random copolymer of ethylene oxide, propylene oxide and phenyl glycidyl ether. It is a method of creating a ground improvement body in which the solidified material composition and the original ground are mixed by agitation by the high pressure jet agitation method to form a ground improvement body,
Supplying the solidifying material composition underground and injecting the solidifying material composition into the ground improvement area with a high pressure jet;
The solidifying material composition comprises a cement, and 0.01 to 1.0 parts by weight of a nonionic polymer surfactant having an aromatic ring in a side chain with respect to 100 parts by weight of dry ash, and 50 Containing at least 140 parts by weight of water,
How to create a ground improvement body.   The method for producing a ground improvement body according to claim 5, wherein the solidifying material composition further contains 0.4 parts by weight or more and 20 parts by weight or less of carbon fibers.   The ground improvement body according to claim 5 or 6, wherein the high molecular weight surfactant is a random copolymer of ethylene oxide, propylene oxide and phenyl glycidyl ether, and the weight average molecular weight thereof is 50,000 or more and 150,000 or less. How to build