JP2005154608A - Grouting agent and grouting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grouting agent of a water glass suspension grouting agent (a cement-water glass grouting agent) with high strength development and excellent durability. <P>SOLUTION: This grouting agent comprises liquid A of an aqueous sodium silicate solution and liquid B of a slurry containing cement, a hardener and a hardening improver such as an organic acid, etc., wherein the hardener is composed of a mixture of calcium aluminate silicate and calcium sulfate. A grouting method uses the grouting agent in a 1.5-shot method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a ground injecting agent used in ground improvement work and water stop work in various civil engineering works, and a ground injecting method using the ground injecting agent.

Conventionally, the ground injecting agent has been widely used for ground improvement work, water stop work and the like.
Here, the ground improvement work is the ground improvement work by injecting chemicals when constructing underground structures such as curtain grouts for reinforcing foundations of large special structures such as dams and power plants, tunnels, oil, and LPG storage bases. Water stoppage works to prevent the spring water generated during excavation work of underground structures below the groundwater level, under the seabed, and in the aquifer ground by injecting an injectant, and to prevent the water tightness of the ground. It is a work to inject an injectant to raise.
In addition to these, the ground injecting agent is also used for preventing the collapse of the ground in the improvement of the ground of ordinary houses and condominiums in poorly drained ground and liquefied ground, and in infrastructure development such as water supply and sewerage.
Thus, the material used for the purpose of solidifying the ground by pouring or strengthening the ground by compacting and dewatering is called a ground pouring agent.

  Various materials are used as ground injection agents, and in the past, non-chemical injections such as clays such as bentonite and ordinary Portland cement were used, but then sodium silicate (hereinafter `` water glass '') System injections and polymer injections such as acrylamide and urethane have also been used.

  However, due to pollution problems caused by the inflow of polymer-based infusate into well water in the Showa 40s, the former Ministry of Construction issued a “provisional guideline on construction work by chemical injection method” in 1974, and some environmental issues The use of polymer-based injections containing harmful substances has been frozen, and currently only two types of materials can be used except in an emergency, cement-based injections and water glass-based injections. Among them, the development of safer and better performance injectants is still desired.

Here, the cement-based injectant is a general term for an injectant that uses ordinary portland cement or blast furnace cement as the main material and only cement, or as an additive combined with bentonite or an inorganic hardener. In order to increase the penetration effect, instead of ordinary Portland cement, ordinary Portland cement and slag are mixed and pulverized to obtain a fine particle cement or ultrafine particle cement.
In general, cement-based injections are alkaline, but relatively safe and have good durability due to the high strength of the cured product. Since it is unsuitable and is in a state where the powder is suspended in water, it has characteristics such as poor permeation performance as compared with a solution-type injection.

  The water glass-based injectant is a generic name for injectants that use water silicate, which is sodium silicate as the main material. Among them, the solution-type injectant is largely dependent on the type of material used as a hardener for water glass. It is divided into suspension type injections.

Here, the solution-type injecting agent is a type in which an inorganic salt, an organic solution, an acid, and an alkali solution in which a curing agent is dissolved in water are used alone or in combination. For example, as an inorganic salt, carbonate, Chlorides, sulfates, borates, and phosphates, and organic solutions include esters-acetic acid monoether glycol, propylene carbonate, aldehydes-formaldehyde, methyl formate, and glyoxal. Is generally sulfuric acid.
Thus, water glass-based solution-type injections are excellent in permeability because there are no particles in the solution, but many have low consolidation strength and therefore poor durability. In addition, depending on the type of curing agent, there are some items that require attention.

On the other hand, a water glass suspension type injection is a material using mainly an inorganic material that is insoluble in a curing agent. For example, the most commonly used is Portland cement, which is generally widely used as the name of the LW method. It is used (for example, refer to Patent Documents 1 to 3).
In addition, materials such as slaked lime and quicklime lime, anhydrous, semi-water, and dihydrate gypsum, slag, and the like are used.
Water glass suspension type injection is a powder in which the hardener is insoluble, but the main material is water glass, so the permeability is better than cement type injection, and the caking strength depends on the type of hardener. However, it is generally higher than the solution type injection and lower than the cement type injection. In addition, many curing agents have high relative safety.
JP-A-11-61123 JP 2001-64649 A JP 2003-26462 A

Patent Document 1 states that “when an aqueous slurry containing a cement-based solidifying material, bentonite and a dispersant is used as liquid A and a water glass aqueous solution is mixed as liquid B, the reaction is cured. Is a civil engineering material characterized in that it has a gel time of 20 seconds or less and a compressive strength (after 1 day) of 7 kg / cm ² or more. As mentioned, it is described that alkali oxycarboxylates such as citric acid, tartaric acid, and gluconic acid are preferable from the functional and environmental viewpoints ”(paragraph [0019]), and the dispersant that is an organic acid salt is used for curing adjustment. It can be said that it is an agent, but “bentonite has a function contradicting the anti-breathing action and the strength deterioration action of the material” (paragraph [0016]). Is bentonite a curing agent? This invention does not use a curing agent for cement.

Patent Document 2 states that “a suspension type grout material using cement and water glass used for the purpose of water stopping and / or strengthening of aquifer ground, and the cement contains 3CaO · SiO ₂ as its component. , 2CaO · SiO ₂ , 3CaO · Al ₂ O ₃ , 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ and gypsum, and the cement component has a SiO ₂ / Al ₂ O ₃ (weight ratio) of 7-12. The invention according to claim 1 is described, and “a cement obtained by adding blast furnace slag to the cement may be used. , Dispersants, setting retarders, pressure-sensitive adhesives, gelling accelerators, extenders (admixtures, etc.) can be used as appropriate "(paragraph [0016]). Agent), curing modifier (setting retarder) However, it is not specifically shown what kind of admixture is used as a component other than blast furnace slag and gypsum.

Patent Document 3 states that “at least cements, silicates and water are mixed prior to injection to form a primary gel, and then breaks down the primary gel as liquid A and water glass aqueous solution as liquid B. A civil engineering material used by mixing and curing the liquid A and the liquid B, wherein the compressive strength of the homogel 28 days after material age is 3 N / mm ² or more. The invention of claim 1 is described, and “the liquid A can be used in combination with one or more other curing agents. Examples of other curing agents include: Acid salts, carbonates, bicarbonates, carbon dioxide, carbonated water, chlorides, aluminates, glyoxals, carbonates such as ethylene carbonate, polyvalent acetates, lime, slag, etc. In addition, liquid A In the scope of the present invention, the scope of the present invention is not impaired. Examples of admixtures that can be used include thickeners, stabilizers, lightweight aggregates, sequestering agents, adhesion improvers, and the like. It can be used in combination of two or more species ”(paragraph [0018]),“ the stabilizer is a component for preventing deterioration of the hardening function due to the hydration reaction of cement in the civil engineering material of the present invention. , For example, pozzolanic substances, oxycarboxylic acids such as citric acid, tartaric acid, gluconic acid, and alkali metal salts thereof ”(paragraph [0020]). However, it is not specifically shown that a material other than silicate is used as a curing agent, and that a curing agent and a curing modifier are combined.

It is also known to use calcium aluminate, gypsum, etc. as a quick setting material for a cement-quick setting material ground injection material (see Patent Document 4).
JP-A-6-330036

  However, as described in Patent Document 4, the cement-quick-setting material-based ground injection material (agent) is clearly distinguished from the cement-water glass-based material (claim 2, paragraph [0009]), No cement quick-setting material (hardening agent) has been used in cement-water glass-based ground injection agents, and a combination of cement quick-setting material (hardening agent) and hardening modifier is used. It was also not known to do.

As mentioned above, the water glass suspension type injection has a solidified body strength to some extent and good permeability, so that it has the widest application range for the ground composed of various geological features. It is. Among them, the LW method using ordinary Portland cement as the curing agent is most often used. However, a curing agent that has good strength development and stable durability has been desired.
Then, this invention makes it a subject to develop the ground injection agent with high strength expression and favorable durability in water glass type suspension type injection (cement-water glass type ground injection agent). It is.

As a result of various investigations, the inventor of the present invention uses a specific curing agent and a curing modifier for cement, and has high strength development among water glass suspension type injections. The present invention was completed by obtaining knowledge that an agent can be obtained.
In the present invention, the following means are adopted to solve the above-mentioned problems.

(1) In the ground injection agent which uses the aqueous solution containing sodium silicate in the A liquid and the slurry containing the cement, the hardening agent and the hardening adjusting agent in the B liquid, the hardening agent is from a mixture of calcium aluminate silicates and calcium sulfate. A ground injection agent characterized by
(2) The ground injection agent according to (1), wherein the curing agent is 70 to 150 parts by mass of calcium sulfate with respect to 100 parts by mass of calcium aluminate silicates.
(3) The ground injection agent according to (1) or (2), wherein the curing agent is used in an amount of 10 to 200 parts by mass with respect to 100 parts by mass of cement in the B liquid.
(4) The ground injection agent according to any one of (1) to (3), wherein the curing regulator is composed of one or more organic acids.
(5) The curing regulator is used in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the cement in the liquid B, as described in any one of (1) to (4), Ground injection agent.
(6) A solution prepared by adding sodium silicate to kneading water is set as A liquid, a curing regulator is previously added to kneading water, a mixture of calcium aluminate silicates and calcium sulfate is added thereto, and a slurry containing cement is further added. A ground injection method characterized in that the liquid A is mixed with the liquid A and the liquid B and then separately pumped and mixed before or after the ground injection.
(7) The ground injection method as described in (6) above, wherein the curing regulator comprises one or more organic acids.
In the following, “part” is based on mass unless otherwise specified.

  In the cement-water glass-based ground injection agent, the present invention uses a mixture of calcium aluminate silicates and calcium sulfate, which are hardeners, in combination with a hardener, thereby providing high strength and good durability. A ground injection method can be obtained, and a ground injection method can be performed using the ground injection agent.

Hereinafter, the present invention will be described in more detail.
The water glass used in the present invention has a molar ratio somewhat different among manufacturers among commercially available water glasses, but the molar ratio in terms of silicon dioxide (SiO ₂ ) and sodium oxide (NaO ₂ ) is 2. 1 to 2.3 are designated as No. 1 sodium silicate, 2.4 to 2.6 are designated as No. 2 silicate, and 3.0 to 3.3 are designated as No. 3 sodium silicate. No. 3 silicate is preferable, and No. 3 silicate is more preferable. Other special water glass or colloidal silica can also be used in combination with the curing agent of the present invention.
20-150 parts are preferable with respect to 100 parts of water, and, as for the quantity of the water glass in the A liquid of this invention, 30-120 parts are more preferable. If the amount of water glass is less than 20 parts, the concentration may be low and may not solidify due to poor condensation. If the amount exceeds 150 parts, the viscosity of the water glass aqueous solution will increase, and mixing with the curing agent or pumping during injection work In some cases, the durability deteriorates, and the shrinkage of the cured body increases and the durability significantly decreases.

  Moreover, 10-200 parts is preferable with respect to 100 parts of B liquid, and, as for the usage-amount of the A liquid used by this invention, 50-150 parts is more preferable. If the amount of the liquid A is less than 10 parts, there is no effect of addition, and there is a case where the condensation or initial strength developability may be lowered. On the other hand, if it exceeds 200 parts, the curing time is long and the long-term strength is low.

  The cement used in the present invention is not particularly limited, and any of ordinary portland cement, early-strength portland cement, blast furnace cement, intermediate heat cement, eco-cement and the like may be used. Of these, ordinary cement and blast furnace cement are preferable.

  Moreover, 10-200 parts is preferable with respect to 100 parts of water, and, as for the quantity of the cement in B liquid used by this invention, 30-100 parts is more preferable. If the amount of cement is less than 10 parts, the concentration is thin, so that the setting or initial strength develops worse. If it exceeds 200 parts, the dispersibility of the slurry becomes poor and kneading becomes difficult, and even when kneaded, the viscosity of the slurry is high. Therefore, there may be a problem in construction.

  In addition, the curing agent used in the present invention is used as a slurry by kneading the content of calcium aluminate silicates and calcium sulfate with water and cement. At this time, the curing regulator is dissolved in the kneading water in advance. Are preferably used.

The calcium aluminate silicates used in the present invention are a mixture of a raw material containing calcia (CaO), a raw material containing alumina (Al ₂ O ₃ ) and a raw material containing siliceous material (SiO ₂ or the like), and kiln. A compound obtained by heat treatment such as baking in aluminum or melting in an electric furnace, wherein CaO and / or Al ₂ O ₃ is partially substituted with silica (SiO ₂ or the like), or CaO and Al ₂ O ₃ is a substance in which silica (SiO ₂ or the like) is dissolved in a small amount in the main component. The mineral form may be either crystalline or amorphous.
Further, the particle size of the calcium aluminate silicates, in terms of permeability to the initial strength development and ground, preferably 4,000 cm ² / g or more in Blaine value, 6,000 ² / g or more is more preferable. If it is less than 4,000 cm ² / g, the initial strength development may be lowered, or the penetration performance may be remarkably deteriorated.

Examples of the calcium sulfate used in the present invention include gypsum. Among the gypsum, type II anhydrous gypsum and natural gypsum are preferable in terms of high strength development.
The particle size of the calcium sulfate is preferably 4,000 cm ² / g or more in Blaine value, 6,000 ² / g or more is more preferable. If it is less than 4,000 cm ² / g, the initial strength development may be lowered.
The amount of calcium sulfate used is preferably 70 to 150 parts, more preferably 90 to 110 parts, per 100 parts of calcium aluminate silicates. If it is less than 70 parts, the initial strength development may be deteriorated, and if it exceeds 150 parts, the short-term strength development may be deteriorated.

  Moreover, 10-200 parts is preferable with respect to 100 parts of cement in B liquid, and, as for the usage-amount of the hardening | curing agent used by this invention, 20-150 parts is more preferable. When the amount of the curing agent is less than 10 parts, there is no effect of addition, and when it exceeds 200 parts, not only the viscosity of the slurry is increased and workability is deteriorated, but also the physical properties are not economical because there is little change at 200 or more. .

  The curing modifier used in the present invention has a role of adjusting the curing time of the curing agent because the hydration reaction occurs when the curing agent is mixed into the cement slurry and hardens.

  The curing modifier used in the present invention comprises one or more organic acids, and examples of the organic acids include gluconic acid, tartaric acid, citric acid, malic acid, and lactic acid, or salts thereof. One or two or more types can be used, and among these, citric acid and salts thereof are preferred from the viewpoint of good kneading properties of the slurry and good initial strength development.

  0.5-10 parts are preferable with respect to 100 parts of cement, and, as for the usage-amount of a hardening regulator, 1-5 parts are more preferable. If the amount of the curing modifier is less than 0.5 part, it is difficult to secure the mixing time of the B liquid containing the curing agent, and if it exceeds 10 parts, the mixing time of the B liquid is further increased but excessively delayed. In some cases, particles in the slurry are likely to settle, causing troubles such as blockage of pumps and hoses, and costly.

As a method for mixing and using the injecting agent of the present invention, a solution prepared by adding a predetermined amount of a water glass stock solution to kneading water is used as A solution, and a predetermined amount of curing adjusting agent is previously added to the kneading water, and calcium aluminate is added thereto. A method in which a mixture of silicates and calcium sulfate is added, and a slurry containing cement is used as B liquid, and after mixing and kneading each of A liquid and B liquid, they are separately pumped and mixed before or after ground injection. (1.5 shot injection method) is preferable, and when the curing time is short, a two shot injection method in which the liquid A and the liquid B are separately fed in the ground is also possible.
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

<Materials used>
Water glass: JIS sodium silicate 3 (Nippon Chemical Industry Co., Ltd.)
Cement: Ordinary Portland cement (product of Electrochemical Industry)
Calcium aluminate silicate: amorphous, brain value 6,000 cm ² / g
Anhydrous gypsum: type II anhydrous gypsum, brain value 6,050 cm ² / g
Curing modifier: Commercial powdered citric acid water: Tap water

<Measurement method>
Gel time: After mixing a water glass aqueous solution and a curing agent slurry, a small amount is transferred to a cup, and the time compression strength at the time when the cup no longer flows even when it is tilted: Stabilized measurement of a cured product of a predetermined age according to JIS A5201 Evaluation of durability (durability): The mold is removed in one day after placing and cured in water. The weight change and appearance change are examined after the curing period of 28 days.
Workability: Judgment is made based on a range in which a sufficient working time can be secured using a construction machine and a target physical property as a water-stopper can be secured.

<Experimental conditions>
As an A liquid, 200 ml of a water glass aqueous solution was prepared by changing the amount of JIS No. 3 water glass added to 100 parts of water and adjusting the concentration. Further, 200 ml of a slurry prepared by putting a predetermined cement, a curing agent mixture and a curing regulator in water and adjusting the same was used as a liquid B, and an equal amount of the liquid A and the liquid B were mixed to measure physical properties.
In addition, B liquid at this time is 80 parts of cement with respect to 100 parts of water, 20 parts of hardener mixture (mixture of 100 parts of calcium aluminate silicate and 100 parts of anhydrous gypsum), and 0.8 part of hardening regulator (with respect to cement). To 1 part).
Moreover, the test was performed in a room at 20 ° C. and a relative humidity of 80%, and the gel time and the compressive strength and stability of the cured body were measured to determine the workability. The results are shown in Table 1.

From Table 1, it can be seen that an injecting agent (experiment No. 1-1) containing a hardener mixture and a curing modifier in cement but not containing water glass has a significantly long gel time and poor workability.
Further, as the amount of water glass added in the liquid A increases, the gel time gradually increases and the compressive strength of σ1 day gradually increases, but the compressive strength of σ28 days is the case where the amount of water glass added is 100 parts. In the case of adding 175 parts (Experiment No. 1-6), the cured product expanded and destroyed during curing (indicated as “collapse” in Table 1). Therefore, it is not preferable to add more than 150 parts of water glass to 100 parts of water.
When the amount of water glass added is 20 to 150 parts (Experiment No. 1-2 to 1-5), gel time, compressive strength, and workability are good.

  <Materials used> are the same as in Example 1. As an A liquid, 200 ml of a water glass aqueous solution prepared by adding 100 parts of JIS No. 3 water glass to 100 parts of water was prepared. On the other hand, the physical property was measured by the same <measurement method> as in Example 1 by changing the addition amount of the curing agent and the amount of cement in the liquid B. The results are shown in Table 2.

From Table 2, it can be seen that an injection (Experiment No. 2-1) containing cement but not containing a curing agent and a curing modifier in the liquid B has a long gel time and poor workability.
It can be seen that the injection agent (Experiment No. 2-7) containing a curing agent and a curing modifier in the liquid B but not containing cement (experiment No. 2-7) has a significantly long gel time, low compressive strength, and poor workability.
Moreover, as the addition amount of the curing agent in the liquid B increases, the gel time is gradually shortened and the compressive strength is gradually increased. When the addition amount of the curing agent is 8 to 160 parts (10 to 200 parts) with respect to 80 parts (100 parts) of cement (Experiment No. 2-2 to 2-6), gel time, compressive strength, construction Good properties.
Furthermore, as the amount of cement in the B liquid increases, the gel time gradually decreases and the compressive strength gradually increases. When the amount of cement in the B liquid is 20 to 200 parts with respect to 100 parts of water (Experiment No. 2-8 to 2-11), it can be said that the gel time, compressive strength, and workability are good. When the amount of cement is 200 parts (Experiment No. 2-11), the viscosity of the liquid B is too high, so there is a problem in workability.

  The same material as in Example 1 was used, and the addition amount of the curing regulator in the B liquid was changed to test the retention time of the B liquid. The results are shown in Table 3.

From Table 3, it can be seen that the injecting agent (Experiment No. 3-1) containing no curing modifier in the B liquid has a very short kneading retention time and poor workability.
As the addition amount of the curing modifier increases, the kneading retention time becomes longer. However, when 15.0 parts (Experiment No. 3-5) is added to 100 parts of cement, the delay is excessive, Since the particles have settled and solidified, it is not preferable to add more than 10 parts of the curing modifier to 100 parts of cement.
When the addition amount of the curing modifier is 1.0 to 10.0 parts with respect to 100 parts of cement (Experiment No. 3-2-3-4), the kneading retention time is long and the workability is good. is there.

Claims (7)

  In the ground injection that uses an aqueous solution containing sodium silicate in liquid A and a slurry containing cement, a hardening agent and a hardening regulator in liquid B, the hardening agent is made of a mixture of calcium aluminate silicates and calcium sulfate. A featured ground filler.   The ground injection agent according to claim 1, wherein the curing agent comprises 70 to 150 parts by mass of calcium sulfate with respect to 100 parts by mass of calcium aluminate silicates.   The ground injection agent according to claim 1 or 2, wherein the curing agent is used in an amount of 10 to 200 parts by mass with respect to 100 parts by mass of cement in the B liquid.   The ground injection agent according to any one of claims 1 to 3, wherein the curing regulator is composed of one or more organic acids.   The ground injection agent according to any one of claims 1 to 4, wherein the curing modifier is used in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of cement in the B liquid.   A solution prepared by adding sodium silicate to kneaded water is designated as liquid A, a curing regulator is previously added to kneaded water, a mixture of calcium aluminate silicates and calcium sulfate is added thereto, and a slurry containing cement is further designated as liquid B. A ground injection method characterized by mixing and kneading each of liquid A and liquid B, separately pumping, and mixing before or after ground injection. The ground injection method according to claim 6, wherein the curing regulator is composed of one or more organic acids.