JPS596278A - Sodium silicate grout - Google Patents

Abstract

PURPOSE:To provide the titled grout usable in a wide range of gel time from flash setting to slow setting, excellent in workability, by incorporating a water- soluble ferrous salt as a major hardener. CONSTITUTION:A grout which comprises as a main material sodium silicate (e.g., water glass No.3 with a concn. of 25vol%) as a principal ingredient and water-soluble ferrous salt (e.g., FeSO4) as a main hardener. Said grout is easy to adjust flash and slow setting, and particularly well suited for composite grouting. Example: 25l of water glass and 25l of water are mixed to form 50l of liq. A, and, separately, FeSO4 as a major hardener and NaHSO4 as a stabilizer are used to make 50l of liq. B. When aiming at a gel time of 6sec, 2.5kg of FeSO4 and 3.7kg of NaHSO4 are mixed as liq. B, and when aiming at 2min, 2.0kg of FeSO4 and 2.9kg of NaHSO4 are mixed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sodium silicate injection material that has excellent workability and can be used in a wide gel time range from instant setting to slow setting.

In recent years, while reviving the simplicity and economy of the Rondo injection method, which was widely used in the 7970s, we have been able to improve the penetration solidification between soil particles through composite injection of instant-setting grout and slow-setting grout, which was impossible with the rod method. A ground injection method has been developed that has been successful. This method involves drilling a hole with a double pipe rond equipped with a special tip monitor, and then injecting instant-setting powder using a co-shot method using the double pipe to form an instant-setting packer around the injection pipe. This construction method completely prevents grout deviation, which is the biggest drawback of the conventional rod construction method, by injecting permeable secondary loosely set grout using the same injection pipe rondo in a 1.5-shot or one-shot method.

The water glass grout used in this construction method is a -grade grout that has instant setting properties and high strength.

In addition, secondary grouts are required to have slow-setting properties, that is, long and stable gelling times, and are permeable. Conventional water glass-based grouting materials generally use strong inorganic acids or metal salts as hardening agents to form instant setting grouts, and weak inorganic acids or organic acids to form slow setting grouts.

It has been impractical, if not impossible, to obtain flash setting grouts and slow setting grouts using the same curing agent. That is, when the concentration of the hardening agent for instant setting grout was lowered and the gelation time was increased, the strength decreased and it was not practical. For example, when the gel time of a commercially available instant setting injection material (using a sodium hydrogen sulfate hardening material) was extended to 2 minutes, the sand gel arc degree decreased to 1.82 by only 9 fΔ. Furthermore, in order to make flash-setting grout using a hardening agent for slow-setting grout, a large amount of hardening agent is required, which is not economical, and there is a limit to achieving a high concentration due to solubility. therefore,
When such conventional water glass-based injection materials are used in the above-mentioned composite injection using the double tube Rondo, the two types of injection materials, fast-setting and slow-setting, must be adjusted completely separately. There was a problem.

This invention was made focusing on the above problems,
The purpose is to propose a silicic acid (IJ)-based injection material that is easy to adjust as fast-setting and slow-setting injection materials and is particularly suitable for composite injections.

Its gist is a sodium silicate-based injection material characterized by containing a water-soluble ferrous salt as the main hardening agent.

As sodium silicate, which is the main material of this injection material, generally No. 1 to No. 3 water glass is used, and for inorganic solution type injection materials, No. 3 water glass with a concentration of 25 volumes is usually used.

Water-soluble ferrous salts, which are the main hardening agents, are selected from inorganic salts such as sulfates, nitrates, and chlorides. This invention is suitable for use because it is easy to handle, inexpensive, and readily available.

When ferrous sulfate is used as the main hard material, the amount used is usually 1.5 K per 100 parts of sodium silicate injection material solution.
f -5.0%. Adding too much will result in instability of the gel, and using too little will result in a decrease in strength, which is unwise. By coexisting a water-soluble acidic inorganic salt, an inorganic acid, or a water-soluble inorganic acid as the main curing agent, an injection material having a wide range of gel time from instant setting to slow setting can be obtained.

That is, for example, using ferrous sulfate as the main hardening agent,
By blending sodium hydrogen sulfate as an acidic inorganic salt, it is possible to adjust the gel time from a standard type with a gel time of 2 minutes to an instant set type with a gel time of 6 seconds. Moreover, by adding magnesium sulfate (enhancing material) to the standard type of 2 minutes, it is also possible to make an instant type with a gel time of 6 seconds.

Sodium hydrogen sulfate is suitable as the water-soluble acidic inorganic salt to be added to the main hardening material, and its amount is 10% of the injection material.
Sulfuric acid and phosphoric acid are useful as the O inorganic acid having an amount of 2.5 to 5 Kf per 1001 injection material, and the blending amount thereof is 1 to 5 kg per 1001 injection material.

Inorganic water bathing salts used as auxiliary materials include sulfates, phosphates, etc., and magnesium, aluminum, and sodium salts are particularly useful. Note that adding too much inorganic acid and water-soluble inorganic salt will cause instant solidification, while adding too little will result in destabilization of the gel. It has greater strength than cured products made of inorganic chemicals, and its -axial compressive strength is generally as shown below.

Homogel strength (1 day) 0.5 to (1,6 to 9/♂ Sand gel strength (1 day) 4.0 to 4.5 V4/humidity 2 or less 2 or less will be explained.

No. 3 water glass solution 25! and water 251 and 5010)k
Separately, a 50/B solution was prepared using ferrous sulfate as the main hardening agent, sodium hydrogen sulfate or sulfuric acid as a stabilizer, or magnesium sulfate as an auxiliary material.

For example, when aiming for a gel time of 6 seconds, mix 2.5 Kf of ferrous sulfate and 3.7 Kf of sodium hydrogen sulfate as liquid B, or 1.7 Kf of ferrous sulfate.

Sodium hydrogen sulfate 3.3Kf, magnesium sulfate 1,
I Kf is used in combination. When aiming for a gel time of 2 minutes, add 2 minutes of ferrous sulfate. Rho and sodium hydrogen sulfate 2
．． 9 Kf, or ferrous sulfate 1.7 to 9 and sodium hydrogen sulfate 5. SK9 is used in combination.

The formulations and experimental results (gelling time and unconfined compressive strength) of both liquids A and B are shown in Tables 1 and 2.

~ ,'' 12/ I〆/ , // / / 〆/ (Table 1) Changes in gel time according to each formulation of injection material 2nd
Table This invention is as described above, and this injection material brings about the following effects.

■ Can be used in a wide range of gelation times from instant setting to about 7 minutes.

■ Adjustment of the gelation time is extremely easy because the concentration of the main curing agent is kept constant and only the amount of stabilizer (sodium hydrogen sulfate or sulfuric acid) added or the amount of auxiliary material (magnesium sulfate) added is changed.

■ In the case of the composite injection method, the process can be simplified because there is no need to adjust two types of injection materials with different hardening materials as in the past.

■ The gelled product has higher uniaxial compressive strength than the cured product of conventional solution-type inorganic drugs.

(2) Ferrous salts, stabilizers, and auxiliary materials used as hardening agents are non-toxic, do not cause environmental pollution, are low cost, and are easily available.

Claims (1)

[Claims] (1) A sodium silicate injection material characterized by containing a water-soluble ferrous salt as a main hardening agent.