JP2018021308A - Back-fill material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a back-fill material that hardens at a temperature below a freezing point or when the temperature resumes to a normal temperature state after falling below the freezing point.SOLUTION: A back-fill material is of a slurry form, and contains (a) slug or fly ash, (b) bentonite, (c) and sodium silicate or sodium metasilicate, where a molar ratio of SiOto NaO of the component (c) is in a range between 1 and 2.3, concentration of the component (a) of the back-fill material is in a range between 25 and 50 mass%, concentration of the bentonite of the back-fill material is in a range between 1 and 30 mass%, concentration of the component (c) of the back-fill material is in a range between 25 and 65 mass%, and the molar ratio of SiOto NaO of the back-fill material is in a range between 0.5 and 2.3.SELECTED DRAWING: None

Description

  The present disclosure relates to backing materials.

  Backing materials are used in the construction of tunnels and shafts. The backing material is injected between the ground cut surface and the segment or the frame. The injected backing material is then cured. As the backing material, a material mainly composed of cement is known (see Patent Documents 1 and 2).

JP-A-7-291703 JP 2004-91535 A

The freezing method may be used as an auxiliary method for constructing tunnels and shafts in the ground. In the freezing method, the inside of the frozen ground is excavated.
A load due to groundwater pressure or earth pressure is applied to the outside of the frozen ground. If the frozen ground alone cannot withstand the external load, complete a part of a structure such as a tunnel or shaft in the frozen ground, and place a backing material between the completed part and the frozen ground. Fill and cure. Then, the next excavation work is performed while supporting the load applied to the outside of the frozen ground by the completed part of the structure and the cured backing material. The above steps are repeated to complete a structure such as a tunnel or shaft. After completion of the entire structure, release the freeze.

  The backing material filled between the completed part of the structure and the frozen ground may not harden due to the influence of the ground at a temperature below freezing, or may become weak in a gelled state. is there. In this case, the load applied to the outside of the frozen ground cannot be supported.

  An object of one aspect of the present disclosure is to provide a backing material that cures at a temperature below freezing or cures when the temperature reaches a temperature below the freezing point.

One aspect of the present disclosure is a slurry-like backing material, comprising (a) slag or fly ash, (b) bentonite, and (c) sodium silicate or sodium metasilicate, the component (c) The molar ratio of SiO _{2 to} Na ₂ O is in the range of 1 to 2.3, the concentration of the component (a) in the backing material is in the range of 25 to 50% by mass, and the backing in the backing material The concentration of bentonite is in the range of 1-30% by mass, the concentration of the component (c) in the backing material is in the range of 25-65% by mass, and the moles of SiO ₂ with respect to Na ₂ O in the backing material. The ratio is in the range of 0.5 to 2.3.

  The backing material of the present disclosure hardens at a temperature below freezing, or hardens at room temperature after becoming below freezing.

  An embodiment of the present disclosure will be described. The form of the backing material is a slurry. The backing material includes (a) slag or fly ash, (b) bentonite, and (c) sodium silicate or sodium metasilicate.

  (A) There exist slag and fly ash as a component. Examples of the slag include steel slag and non-ferrous slag. The density | concentration of (a) component in a backing material exists in the range of 25-50 mass%, for example. The concentration of the component (a) is a value with the total mass of the backing material (including a solvent such as water) as the denominator and the mass of the component (a) as the numerator. The component (a) may be one of slag and fly ash, or may include both.

  The concentration of bentonite in the backing material is in the range of 1 to 30% by mass. The concentration of bentonite is a value with the total mass of the backing material (including a solvent such as water) as the denominator and the mass of bentonite as the numerator.

  As component (c), there are sodium silicate and sodium metasilicate. The component (c) may be one of sodium silicate and sodium metasilicate, or may include both. The density | concentration of (c) component in a backing material exists in the range of 25-65 mass%, for example. The concentration of the component (c) in the backing material is a value with the total mass of the backing material (including a solvent such as water) as the denominator and the mass of the component (c) as the numerator.

  The backing material may further contain, for example, (d) soda ash. The concentration of soda ash in the backing material is, for example, in the range of 3 to 25% by mass. The concentration of soda ash is a value with the total mass of the backing material (including a solvent such as water) as the denominator and the mass of soda ash as the numerator. Soda ash has the effect of increasing the strength of the backing material. When the concentration of soda ash is 3% by mass or more, the strength of the backing material is further increased. When the concentration of soda ash is 25% by mass or less, it is difficult to shorten the curing time, and it is easy to secure a sufficient construction time.

  The backing material may further include components other than (a) to (d), for example. Examples of other components include water, solvents other than water, and calcium hydroxide. Sodium hydroxide acts as a gel time adjusting agent, for example.

Examples of the blending in the backing material of the present disclosure include the following blending examples. This formulation includes slag, bentonite, sodium silicate, soda ash and water. The form of the blending example is a slurry.
(Formulation example)
Molar ratio of SiO _{2 to} Na ₂ O in sodium silicate: 1 to 2.3
Concentration of slag in backing material: 25-50% by mass
Concentration of bentonite in the backing material: 1 to 30% by mass
Concentration of sodium silicate in the backing material: 25-65% by mass
Concentration of soda ash in the backing material: 3 to 25% by mass
Molar ratio of SiO _{2 to} Na ₂ O in the backing material: 0.5 to 2.3
The said combination example has an effect of at least one of the following (A) and (B).

  (A) When a backing material is used in the freezing method, the backing material freezes. The backing material undergoes a curing reaction while being frozen, so that strength can be obtained. Further, since the curing reaction proceeds while the backing material is frozen, bleeding and volume reduction are unlikely to occur.

(B) When a backing material is used in the freezing method, the backing material is frozen and a certain strength can be obtained by freezing. Thereafter, when the room temperature is reached, the curing reaction of the backing material proceeds and further strength can be obtained.
Example 1
1. Manufacture of backing material The backing materials of S1-S6 were manufactured by mixing each component shown in Table 1. The slag in Table 1 is a product name manufactured by D.C. Bentonite is a product name manufactured by Hojun Co., Ltd .: Hakuba. Sodium silicate is a product of Fuji Chemical Co., Ltd. Sodium metasilicate is a product of Yoshida Chemical Co., Ltd. Soda ash is soda ash (light ash) generally used for industrial purposes.

For S1 to S6, the molar ratio of SiO _{2 to} Na ₂ O in component (c) (indicated as “(c) component SiO ₂ / NaO ₂ ” in Table 1), SiO _{2 to} Na ₂ O in the backing material the molar ratio (referred to as Table 1, "SiO ₂ / NaO ₂ of Urakomizai"), the concentration of SiO ₂ in Urakomizai, the concentration of slag in Urakomizai, the concentration of bentonite in Urakomizai, in Urakomizai Table 2 shows the concentration of the component (c) and the concentration of soda ash in the backing material.

2. Evaluation of Backing Material For S1 to S6, uniaxial compressive strength was measured in accordance with JIS A 1108. The measurement was carried out at −10 ° C. for 7 days and then allowed to stand at room temperature, and the test specimen was carried out at the stage where the temperature reached room temperature. Table 3 shows the measurement results.

As shown in Table 3, the uniaxial compressive strengths of S1 to S4 were significantly high. This represents that S1 to S4 were cured at a temperature of −10 ° C. or cured at room temperature. “Not self-supporting” in Table 3 indicates that the specimen was not self-supporting and the uniaxial compressive strength could not be measured.
(Other embodiments)
As mentioned above, although the form for implementing this indication was demonstrated, this indication is not limited to the above-mentioned embodiment, and can carry out various modifications.

(1) In the present disclosure, fly ash may be used instead of part or all of the slag.
(2) In the present disclosure, the component (c) may be only sodium silicate, may be only sodium metasilicate, or may be a mixture of sodium silicate and sodium metasilicate. Also good.

  (3) A function of one component in each of the above embodiments may be shared by a plurality of components, or a function of a plurality of components may be exhibited by one component. Moreover, you may abbreviate | omit a part of structure of each said embodiment. In addition, at least a part of the configuration of each of the above embodiments may be added to or replaced with the configuration of the other above embodiments. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

  (4) In addition to the above-described backing material, the present disclosure can be realized in various forms such as a system using the backing material as a constituent element, a construction method using the backing material, and the like.

Claims (2)

A slurry-like backing material,
(A) slag or fly ash, (b) bentonite, and (c) sodium silicate or sodium metasilicate,
The molar ratio of SiO _{2 to} Na ₂ O in the component (c) is in the range of 1 to 2.3,
The concentration of the component (a) in the backing material is in the range of 25 to 50% by mass,
The concentration of the bentonite in the backing material is in the range of 1 to 30% by mass,
The concentration of the component (c) in the backing material is in the range of 25 to 65% by mass,
The backing material in which the molar ratio of SiO _{2 to} Na ₂ O in the backing material is in the range of 0.5 to 2.3. The backing material according to claim 1,
In addition, a backing material containing soda ash.