KR20010090686A - Method of Grout Injection and Grout Injection Material - Google Patents

Abstract

PURPOSE: Provided are a grout injecting method and a grout injecting material which can prevent segregation, has fluidity and viscosity for retaining good filled-up properties, is low in bleeding, and exhibits sufficient strength without loss of hardening ability. CONSTITUTION: In the grout injecting method, cement suspension containing about 200-500 kg cement per 1 m¬3 grout and basic aluminum sulfate solution are mixed as main materials and injected into a gap or a cavity, such that (a) the basicity of aluminum sulfate is equal to 2 or more and that (b) the following formula is satisfied: (cement weight/100) ÷ {alumina weight in aluminum sulfate/(basicity of aluminum sulfate)1/2} >= 1.33. As a result, flowable or plastic grout is obtained.

Description

Grout Injection Method and Grout Injection Material {Method of Grout Injection and Grout Injection Material}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a grout injection method for filling (e.g., back-filling of tunnels) with large gaps in the ground or large gaps in the ground, such as the cavity between the ground and the structure. Moreover, it is related with the grout injection material used for this.

Specifically, it is a grout injection method using a sticky grout of aluminum hydroxide (hereinafter referred to as aluminum hydroxide sol) of the cross-linked precipitate formed by adding cement as the main material and adding basic alumina sulfate (aluminum sulfate).

The grout used for the cavity filling is less bridging (usually 2 to 5%) and prevents material separation (sedimentation of particles when aggregate is added), Fluidity is required in order to improve the transportability and filling properties, and a strength of at least a certain level (usually about 2 to 30 kgf / cm ² ) is required.

As the grout for filling used for this purpose,

(1) Cement is used as an excellent material in strength, durability and economical efficiency.

(2) A sticky material is used to bridge the grout, prevent material separation and maintain fluidity and fillability.

Among the above, the object of this invention is the adhesive material of (2).

As the adhesive material, the most commonly used montmorillonite clay mineral (commonly referred to as bentonite) is conventionally used.

This bentonite powder is dispersed and swelled in water (especially clear water) to obtain a viscous liquid having adhesiveness (also referred to as viscosity).

When cement is added to this, it reacts and a kind of gelation reaction loses swelling characteristic peculiar to bentonite, but the viscosity increases rapidly and a grout with less bridging can be obtained.

However, since bentonite is powder, it is necessary to add and mix water in the field, and there is a problem in construction and management because the degree of swelling (longer) varies depending on the contact time with water.

In addition, bentonite has an extremely low swelling degree (requires large amounts of bentonite) in water containing electrolyte ions other than clear water (sea water or alkaline water mixed with cement). have.

On the other hand, there is an aluminum salt solution as another pressure-sensitive adhesive, which has already been filed and published by the inventors of the present application (Japanese Patent Application Laid-open No. 48-88015).

When the pressure-sensitive adhesive is added with an acidic aluminum salt solution to the alkaline cement suspension, both of them react to form a sticky aluminum hydroxide sol, whereby a grout similar to bentonite is obtained.

However, this reaction is the neutralization reaction of alkali and acid, that is, the alkali component (mainly calcium hydroxide) in cement is consumed (neutralized) with the acid component of alumina sulfate (aluminum sulfate).

On the other hand, the adhesive grout is generally used containing 200 to 500 kg of cement (about 2 to 30 kgf / cm 2) per m 3 from the desired strength.

For this reason, when adding the alumina sulfate required for grouting so that bridging will be 2 to 5% or less with respect to this amount of cement, there is a drawback that the cement loses its curing ability (according to the above-mentioned application, the initial pH of the cement suspension Value of 11.5 or higher).

For this reason, in the above-mentioned prior application, the situation is dealt with by adding alkali components, such as lime and soda carbonate, to cement.

This invention is made | formed in order to solve the above-mentioned conventional subject, and it becomes possible to add this basic alumina sulfate by a target amount by making cement into a main material and adding basic alumina sulfate to it, and as a result the material An object of the present invention is to obtain a grout which can prevent separation, has adhesiveness to maintain fluidity and filling properties, and has little bridging and can exhibit sufficient strength without losing curing ability.

The grout injection method of the present invention is based on a cement suspension containing about 200 to 500 kg of cement per cubic meter of grout in a gap or cavity, and a basic alumina sulfate solution as main materials.

[a] the basicity of alumina sulfate is 2 or more,

[b] (cement weight / 100) + (alumina weight in alumina sulfate / basicity of √ alumina sulfate) have a value of 1.33 or more

It is characterized by mixing and injecting to satisfy the conditions to produce an aluminum hydroxide sol.

In addition, the grout injection material of the present invention is a cement suspension and basic alumina sulfate solution containing about 200 to 500 kg of cement per cm 3 of grout.

[a] the basicity of alumina sulfate is 2 or more,

[b] (cement weight / 100) + (alumina weight in alumina sulfate / basicity of √ alumina sulfate) have a value of 1.33 or more

It is adjusted so as to satisfy the conditions and is used as the main material, and is injected into the gap or the cavity.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described.

The present invention relates to a sticky grout in combination with cement and alumina sulfate.

Unlike other ions such as iron, aluminum ions (Al ³⁺ ) of (aqueous aluminum salt) such as alumina sulfate are present in the form of [Al (0H ₂ ) ₆ ] ³⁺ , and Al ³⁺ It alone does not exist in aqueous solution. Adding an alkali agent (cement in the present invention) to the aqueous aluminum salt solution produces a white bulging precipitate.

Al ³⁺ + 30H ^- Al (0H) ₃

Al (0H) ₃ (aluminum hydroxide) is not a simple molecule, but a large molecule in which a complex of a cube having six 0H (hydroxyl ions) around Al shares 0H ⁻ and is multi-polymerized.

³⁺ 3n0H + n [Al (0H _{2) 6]} ^- Aln (0H) _3n + 6nH ₂ O

The reason why the aluminum hydroxide solution becomes an alternating solution, that is, an aluminum hydroxide sol, is because such large molecules are generated.

Thereby, cement is added as an alkali agent to the alumina sulfate aqueous solution, and a sticky aluminum hydroxide sol is produced | generated, and grout with few bridgings can be made.

However, in the range of 200 to 500 kg of cement per 1 m ³ as in the present invention, since the absolute amount of acid is large in general acidic alumina sulfate, when adding the amount necessary to make bridging 2 to 5% or less, cement The hardening ability of the was lost, and the expression of strength could not be obtained.

As a result of performing various experiments in order to solve this problem, the inventors of the present invention have been able to solve the conventional problem by using basic alumina sulfate having a small absolute amount of acid instead of acid alumina sulfate.

That is, by using basic alumina sulfate, the consumption (neutralization) of the alkali component of the cement can be reduced, and as a result, it is possible to add a large amount, so that the grout can exhibit sufficient strength without losing the curing ability while having less bridging. To complete.

In the present invention, for a grout containing about 200 to 500 kg of cement per m 3 of grout, it is necessary to satisfy the following two conditions.

(1) Cement should exhibit sufficient strength without losing hardenability.

(2) A grout with 5% bridging is to be obtained.

It was found that the satisfaction of these conditions was determined by the degree of basicity of alumina sulfate, its amount and the amount of cement.

That is, the condition of [a]: The basicity of alumina sulfate is about 2 or more.

When the basicity is close to normal acidic alumina at about 2 or less, since the acidity becomes strong, only a small amount of alumina sulfate can be added to cure the cement, so bridging is inversely proportional to the amount of aluminum hydroxide sol produced. It is not suitable as.

The basicity of the alumina sulfate is preferably 2 or more, preferably 2.5 or more.

In addition, the condition of [b]: cement / 100 + Al ₂ O ₃ / Basicity = 1.33 or more.

Here, "cement" means cement weight, "A1 ₂ O ₃ " means the weight of Al ₂ 0 ₃ in alumina sulfate, and "base group" means basicity of alumina sulfate.

When the relationship between the degree of basicity of alumina sulfate, the amount thereof, and the amount of cement is 1.33 or more in the formula [b], it has been found that the cement is sufficiently cured.

That is, in the present invention, in a grout containing about 200 to 500 kg of cement per m 3, the basicity of the alumina sulfate is about 2 or more (the condition of [a]), the degree of basicity of the alumina sulfate and its amount, And brittleness is 2 to 5% or less by satisfying the conditions (conditions in [b]) of the relationship between the amount of cement, and an adhesive grout capable of sufficiently exhibiting hardening of the cement can be obtained.

In addition, the basicity of alumina sulfate is obtained from the analytical value by the following formula.

In the present invention, alumina sulfate is specified among the aluminum salts for the following reasons.

In other words, when alumina sulfate and cement react, insoluble neutral calcium sulfate becomes a safe substance that does not elute from the grout. In addition, alumina sulfate is the least expensive among aluminum salts and is produced in large quantities.

On the other hand, poly aluminum chloride produced in a large amount is excluded from the scope of the present invention because soluble sodium chloride is produced by reaction with cement and eluted out of the hardened grout to adversely affect concrete structures and the like.

The cement used in the present invention is generally referred to as cement and is typically portland cement.

As aggregates (or extenders) which can be added to the present invention, sand, flyash, lime, primary mineral fine powders (rock, quartz, limestone, dolomite, etc.), clay minerals (bentonite, porcelain soil, etc.) In addition, field-produced soil (silt, soil containing clay powder, and shield completion), etc. may be mentioned, and one or two or more kinds of these aggregates may be combined.

Moreover, the blowing agent (foaming agent etc.), dispersing agent, retardant, early strength expressing agent, etc. which are added to the conventional grout can be added according to the objective.

The construction of the grout of the present invention is carried out by the following two methods.

(1) one-component system

When the alumina sulfate is relatively low and the bridging is not very strong (1-5%), the grout maintains fluidity. In the present invention, the grout which maintains such fluidity is called a fluidized bed grout.

The construction of this fluidized bed grout is carried out in a one-liquid manner. That is, water, cement, alumina sulfate, or aggregates and additives are added to a combination container such as a mixer, and if necessary, the adhesive grout containing aluminum hydroxide sol and cement as a main component is combined at one time and pumped by one infusion pump. It is performed by injection into a back.

(2) two-component method

On the other hand, when alumina sulfate is used a lot and there is no bridging (0%) and the adhesion (ultra high viscosity) degree is very strong, the grout is in a state of maintaining non-flowability.

In the present invention, the grout which maintains such a non-flowability is called a plastic phase grout.

This plastic phase grout does not flow, but refers to a property that is easily fluidized when pressurized (by a pump or the like).

The construction of the plastic phase grout is carried out in a two-part system. In other words, cement or suspension, to which aggregate or additive is added, is called A liquid, alumina sulfate solution is called B liquid, and each is pumped by a separate infusion pump, and A and B liquid are combined and mixed near the inlet, The grout modified by aluminum hydroxide sol and cement-based plastic grout by the reaction of the cement with alumina sulfate is injected into a desired cavity or the like.

In addition, the determination of whether to deteriorate from the one-liquid fluidized phase to the non-flowing plasticized phase is somewhat dependent on the properties of the grout. After filling the grout therein, the cylinder is gradually lifted, and the grout spread at that time, that is, the diameter is measured and expressed in cm. Plastic phase grout.

In summary, the adhesive grout injection method of the present invention is a grout for use in the gap or cavity in the ground or the filling injection method of the gap or cavity between the interface between the ground and the structure, and the cement is about 200 to 1 m 3 of grout. In the cement suspension containing 500 kg and the basic solution of alumina sulfate, the basicity of [a] alumina sulfate is about 2 or more, and [b] cement / 100 + Al ₂ O ₃ / √basicity = 1.3 or more (wherein Al ₂ 0 ₃ is It is characterized by mixing so as to satisfy the condition (weight of alumina in alumina sulfate) to produce an aluminum hydroxide sol.

Hereinafter, the Example of this invention is given and it demonstrates in detail.

As shown in Table 1, basic alumina sulfate used for the experiment is five kinds from which basicity differs, and cement is a portland cement normally. The weight of Al ₂ O ₃ contained in one liter of the alumina sulfate solution is approximately 100 g.

Type of Alumina Sulfate Used in Experiment Kinds basicity Weight in g of Al ₂ O ₃ in 1 liter of alumina sulfate solution B-1 0.5 96.7 B-2 2.5 110.5 B-3 8.6 96.8 B-4 28.8 94.0 B-5 58.0 94.1

<Experiment-1>

For a certain amount of cement (corresponding to 200 kg per m 3 of grout), an experiment was conducted to confirm the hardening of the cement when the alumina sulfate of each basicity shown in Table 1 was added, and the results of Table 2 were obtained.

The experiment combined the grout in a plastic bag (5 cm in diameter, 30 cm in length) and confirmed the curing state after 3 days by touch.

As shown in Table 2, in each experiment (No. 1 to 18), 60 g of cement (weight is indicated by symbol C) was dissolved in about 200 to 270 ml of water, and basicity (marked by symbol B). About 3 to 50 ml of different alumina sulfates were added. The whole mixture of water, cement and alumina sulfate was made to be 300 ml. The weight of Al ₂ O ₃ in the added alumina sulfate (denoted by the symbol A in g) is about 0.3 to 5 g.

In the second column on the right side of Table 2, the value of the following formula [b] is shown.

[b] C / 100 + A / B

In addition, the determination result about hardening of grout (cement) is shown in the rightmost column of Table 2. FIG.

According to the experimental results of Table 2, the smaller the basicity (B) of the alumina sulfate, the smaller the amount of alumina sulfate, the cement was not cured (Comparative Example-2), it is necessary to further reduce the amount of alumina sulfate to cure It can be seen that there is (Comparative Example-1). In the case of Comparative Example-2, the cement loses the curing ability and cannot exhibit strength.

On the other hand, it turned out that cement becomes hard even if a large amount of alumina sulfate is added, so that the basicity (B) of alumina sulfate is large. When the basicity (B) of alumina sulfate and the amount thereof (indicated by the amount A of Al ₂ O ₃₎ are added to the cement, the results are summarized as follows. Could.

That is, the relationship between the cement weight (C), the basicity (B) of alumina sulfate and the added weight (A) of Al ₂ O ₃ is

[b] C / 100 + A / B = 1.33 or more

In other words,

[b] cement / 100 + Al ₂ O ₃ / Basicity = 1.33 or more

Can be displayed as

Based on the value of the formula [b], the cement was not cured when it was about 1.33 or less, but it was confirmed that the cement was sufficiently cured when it was about 1.35 or more.

In addition, in the formula [b], hardening can be determined even if the cement is increased or decreased.

In addition, in the experiment of Table 2, as shown in Table 1, the basicity (B) of the alumina sulfate used the thing of the range of 2.5-58.0. In addition, the value of the formula [b] reaches the range of 1.33 to 2.74 as for what grout | hardening of grout was judged to be favorable (circle mark in Table 2).

<Experiment-Ⅱ>

Bridging and flow values for the value of the formula [b] in Table 2 to sufficiently cure the cement can be used as grout in the case of a compound of about 1.33 or more (200 to 500 kg of cement per m 3 of grout). And uniaxial compressive strength was measured to obtain the results in Table 3.

As shown in Table 3, in each experiment (No. 19 to 26), cement was dissolved in about 240 ml of water in the range of about 60 to 150 g (symbol C), and sulfuric acid having a different basicity (symbol B) About 8-50 ml of alumina was added respectively. The whole mixture of water, cement and alumina sulfate was made to 300 ml.

Table 3 shows the value of the formula [b]. In addition, measurement results of bridging, flow values, and uniaxial compressive strength are displayed.

According to the experimental result of Table 3, the experiment No. 19 (Comparative Example-11), in Table 2 (Comparative Example-1), although the cement is sufficiently hardened (500 g of cement per 1 m 3 of grout, the value of the formula [b] 1.47), alumina sulfate (basic degree of 0.5) Since the amount of%) is small and sufficient aluminum hydroxide sol cannot be produced, bridging is very large. For this reason, it is not suitable as grout and was excluded from the scope of the present invention.

In contrast, Experiment No. As shown in 20 to 26 (Examples 9 to 15), the basicity of alumina sulfate is about 2 or more, and the value of the formula [b] is about 1.33 or more (200 to 500 per m 3 of grout in Examples 9 to 14). Kg of cement), bridging is 5% or less, and it is understood that the possibility of solidification strength of 2 to 25 kgf / cm 2 is sufficient grout.

In addition, when the addition amount of basic alumina sulfate is relatively small, the flow value is about 13 or more in the fluidized phase grout (Examples 9, 11, 13, and 15), and in many cases, it can be seen that it is a plasticized phase grout. Example 10, 12, 14).

As mentioned above, in this invention, it was confirmed that bridging is about 2 to 5%, and sufficient strength is obtained that the basicity of alumina sulfate is about 2 or more.

In addition, although not shown in the experimental example, when the aggregate and the additive were added to the examples of Table 3, bridging was 2 to 5% or less, and a good fluidized and plasticized grout was obtained in which the cement was sufficiently cured.

As described above, according to the present invention, a cement grout containing about 200-500,000 kg of cement per cubic meter of grout and basic alumina sulfate is used as a grout to be filled and injected into a cavity in the ground, a cavity between the ground and the structure boundary.

[a] the base of the alumina sulfate is about 2 or more,

[b] Cement / 100 + Al ₂ O ₃ / √base = 1.33

By adjusting it so that it was possible to obtain the adhesive grout which bridging is 2 to 5% or less and sufficient strength is obtained.

In addition, according to the present invention, it is possible to add the basic alumina sulfate in a desired amount by using cement as the main material and adding basic alumina sulfate. Thereby, a grout which can prevent material separation, has adhesiveness for maintaining fluidity and filling properties, has little bridging, and can exhibit sufficient strength without losing curing ability can be obtained.

In addition, such a grout injection material and a grout injection method using the same can be obtained.

Claims (2)

Cement suspension containing about 200 to 500 kg of cement per cubic meter of grout in a gap or cavity, and basic alumina sulfate solution as main materials, [a] the basicity of alumina sulfate is 2 or more, [b] (cement weight / 100) + (alumina weight in alumina sulfate / basicity of √ alumina sulfate) have a value of 1.33 or more A grout injection method characterized by mixing and injecting to satisfy the conditions to produce an aluminum hydroxide sol. A cement suspension containing about 200 to 500 kg of cement per m 3 of grout, and a basic alumina sulfate solution, [a] the basicity of alumina sulfate is 2 or more, [b] (cement weight / 100) + (alumina weight in alumina sulfate / basicity of √ alumina sulfate) have a value of 1.33 or more A grout injection material, which is adjusted to satisfy a condition to be a main material and injected into a gap or a cavity.