JPS5925876A - Grouting method - Google Patents

Abstract

PURPOSE:To prevent the deterioration of working environment due to the occurrence of much dust, by adding water, etc. to a mixture of lime with gypsum dihydrate, etc. in a specific proportion, mixing water with the resultant granulated hardening agent at a site of an execution work, mixing the resultant mixture with an aqueous solution of sodium silicate, and injecting the resultant grout into the ground. CONSTITUTION:(A) 100pts.wt. mixture of (i) lime with (ii) a gypsum selected from gypsum dihydrate, alpha-hemihydrate gypsum, beta-hemihydrate gypsum and IItype anhydrous gypsum at (1:3)-(3:1) weight ratio between the components (i) and (ii) is mixed with preferably 5-30pts.wt. water and if necessary 0.05- 5pts.wt. setting retarder, e.g. sodium citrate, and 0.25-5.0pts.wt. dispersing agent, e.g. sodium lignin sulfonate, and 20-200pts.wt. aggregate, e.g. colloidal cement, and then granulated to give a hardening agent mixture having preferably <=1mm. particle diameter. Water is then added to the mixture to give (A) a solution, which is then mixed with (B) an aqueous solution of sodium citrate, preferably sodium citrate No.3. The resultant grout is then injected into the ground. USE:Suitable for strengthening poor subsoil in closed places, e.g. tunnels, shields, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chemical injection method using a silicate grout using a specific lime-gypsum mixture as a hardening agent.

Conventionally, chemical injection methods (grouting methods) have been known in which various chemical solutions are injected into the ground and hardened in the ground in order to strengthen soft ground and to stop water from springs. So-called silicate-based grouts, which are chemical solutions made from soda as the main ingredient and a hardening agent, are widely put into practical use because they are inexpensive and less dangerous than other chemical grouts. .

Recent trends in chemical injection construction methods include research to develop grouts with superior performance, while it is desired to develop construction methods that are both easy to work with and highly safe.

The present inventors previously proposed a grout with various excellent performances, particularly a grout that exhibits particularly excellent effects when applied to the instant setting method, in Japanese Patent Application No. 53-158674 (Japanese Patent Application Laid-Open No. 55-86879). In (a) lime and (
b) (a):(b) -1:3 to 3:1 ( The authors proposed a chemical solution in which a mixture of the following proportions (by weight) was used as a curing agent, and this was combined with sodium silicate.

When implementing this chemical injection method for grout, conventionally, at the construction site, fine powders of both components (a) and (b) above are mixed with water to form a hardening agent slurry (hereinafter referred to as liquid B). A method is used in which the liquid B is mixed with an aqueous sodium silicate solution (hereinafter referred to as liquid A), and the mixture is injected into the ground.

However, in this method, a large amount of dust of both components (a) and (b) is generated when preparing liquid B, which significantly deteriorates the working environment at the construction site. This is especially true in confined spaces such as

As a result of various studies aimed at correcting such conventional drawbacks, the present inventors granulated a powdered curing agent mixture in advance in a factory or other place where dust is sufficiently controlled, and applied the following treatment to the resulting granules. ] The inventors of the present invention discovered that the objective could be achieved by adding water at the second time and preparing the B solution.

In other words, the present invention requires ``during construction, water is added and mixed to the following mixture to prepare liquid B, and then liquid B and liquid A prepared from an aqueous sodium silicate solution are mixed and injected into the ground. A chemical injection method characterized by:

The main points are as follows.

The present invention will be explained below. The sodium silicate used in the present invention has a molar ratio of 5i02/Na2O of 2 to 4.
Examples include sodium silicate, but usually JISK-140
No. 1 to No. 3 sodium silicate specified in No. 8, particularly No. 3 sodium silicate is preferably used.

Although sodium silicate is generally in the form of an aqueous solution, it is further diluted with water during construction to form an aqueous solution with an appropriate concentration suitable for the purpose of construction.

For example, a sodium silicate aqueous solution (liquid A) and a hardening agent slurry! J
- When JI No. 83 sodium silicate is used as the sodium silicate in the usual construction method of mixing equal volumes of (liquid B) and injecting it into the ground, the sodium silicate is usually 40 to 180 parts by volume diluted with water to give 200 volumes. The treated soil can be made stronger as the concentration of sodium silicate in the A solution is increased.

In the present invention, the curing agent for curing the sodium silicate aqueous solution in the ground is selected from the group consisting of lime (hereinafter referred to as component (a)), dihydrate gypsum, α-hemihydrate gypsum, β-hemihydrate gypsum, and ■-type anhydrite. At least one type of gypsum [hereinafter, (b
) components] are mixed in a ratio of 1:3 to 3:1 by weight. Examples of the component (a) used in the present invention include slaked lime and quicklime, and these can also be used in combination.

On the other hand, any type of gypsum dihydrate, α-hemihydrate gypsum, and β-hemihydrate gypsum used as component (b) can be used, but it is usually used during production or during salt production, such as phosphoric acid, hydrofluoric acid, or ammonium sulfate. Chemical gypsum, etc. produced by-product in titanium smelting and flue gas desulfurization processes are preferably used.

The ■-type anhydrite used in the present invention is obtained by firing dihydrate gypsum and hemihydrate gypsum at a temperature of 400°C or higher, and is usually produced as a by-product during wet phosphoric acid production or flue gas desulfurization process. Those obtained by calcining dihydrate gypsum, hemihydrate gypsum, etc. are preferred because they are inexpensive and easily available; however, for example, natural type 1 anhydrite may also be used.

Similar to component (a), these components (b) can also be used not only individually but also in combination.

Even if a sodium silicate aqueous solution of each component (a) and (b) is cured alone, the strength of the cured product is not satisfactory, but when a sodium silicate aqueous solution is cured by using both components together, The strength of the cured product is improved, and component (a) and (
The strength of the cured product is maximized when the mixing ratio of the components b) is 1:3 to 3:1 by weight.

The reason why a mixture of components (a) and (b) in a ratio of 1:3 to 3:1 (weight ratio) is used as a curing agent in the present invention is for the reason described above.

6- In the present invention, both components (a) and (b) are preferably ground as finely as possible from the viewpoint of effectiveness; for example, the particle size when measured by the Blaine method is 3.
It is desirable to use one that has been pulverized to a particle size of 000 to 9000 cd/11.

Particle size is 3000 crd/! If the grain size is less than i', there is a risk that the gel time of the grout will be delayed and the strength of the treated ground will be reduced.On the other hand, if the grain size exceeds 9000 cd/I and the grain size is too coarse, It is not easy to grind and is not economically available.

In the present invention, both powdered components (a) and (b) are specified in the present invention at a factory or other place where dust is sufficiently controlled in advance so that hardening agent dust is not generated at the construction site. After mixing in the above-mentioned predetermined proportions and adding a set retardant, dispersant, aggregate, etc. as necessary, granulation is carried out according to a conventional method to obtain a granular curing agent mixture (hereinafter referred to as
It is referred to as the curing agent mixture of the present invention. ) is manufactured.

During granulation, the amount of water added to the above (a) and (b) mixture powders can be varied depending on the composition, particle size, etc. of the raw powder hardening agent mixture, but if the amount of water is too small, granulation may fail. If the amount of water is sufficient, there is a risk that dust will be generated from the resulting granulated product, while if the amount of water is too large, the mixture will become a slurry, making granulation impossible. For this reason, the amount of water used is preferably about 5 to 30 parts by weight per 100 parts by weight of powder.

The curing agent mixture of the present invention obtained by granulation is added with water at the time of construction to prepare a slurry IJ-(Liquid B) in which fine powder of the curing agent is uniformly dispersed in the liquid. Since it is preferred that the curing agent mixture of the present invention disintegrates quickly, the mechanical strength of the granules does not necessarily need to be high in the present invention, and therefore a binder is not normally required for granulation, and In principle, there is no need to dry the grains after graining.

The curing agent mixture of the present invention is a key that does not generate dust, and the finer the grains are, the faster the particles will disintegrate during the preparation of liquid B, which is advantageous.
It is usually desirable to produce grains with an average grain size of about one fin or less.

No special equipment is required for the granulation, and a mixer or the like commonly used for granulation of this type of powder is preferably used.

Depending on the manufacturing conditions during granulation, quicklime, α hemihydrate gypsum, β
Hydraulic substances such as hemihydrate gypsum and ■-type anhydrite may react with granulation water to form locally strong particles, or the particles may solidify during transportation or storage.

In the present invention, in order to avoid such troubles,
During granulation, a setting retarder is added to the raw powder hardening agent mixture as necessary.

Set retarders used include citric acid, sodium citrate, tartaric acid, and storium tartrate.

Oxycarboxylic acids and their salts such as potassium tartrate; borates such as boric acid and sodium borate; carbonates such as sodium carbonate, potassium carbonate, aqueous sodium carbonate, potassium hydrogen carbonate; Sodium hydroxide, sodium sulfate.

Chlorides such as sodium tripolyphosphate, sodium chloride, magnesium chloride, ammonium chloride; Fe 5 +,
Cr 6+ * A13+ sulfate; gelatin, decomposed seratin, casein, calcium caseinate, egg albumin, γ-globulin, zein (a type of prolamin), pepsin, pectin, papain 1 def-L tannin, gum acacia (gum arabic), Trahegacanth gum, Congo red, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, polyethylene glycol, alumina gel, silica gel, simi sugar, hexametaphosphoric acid.

Examples include one or more of ethylenediaminetetraacetate, peptone, and polypeptone.

The amount of these setting retarders to be used may vary depending on the type used, the storage time of the curing agent mixture of the present invention, etc., but it is usually 0.05 to 5 parts by weight per 100 parts by weight of the raw powder curing agent mixture. Use parts by weight.

Furthermore, in the present invention, when preparing liquid B, (a), (b
) 1 which improves the dispersion of fine powder of each component into the liquid;
0- In order to reduce the viscosity of liquid B, an appropriate dispersant is added to the raw powder curing agent mixture during granulation, if necessary.

As the dispersant used for this removal, water reducing agents, dispersants, etc. that are normally used in cement are suitable. , melamine-formalin condensate sulfonate.

Examples include one or more kinds of β-naphthalene sulfonate.

If the amount of these dispersants used is too small, the expected effect will not be obtained, while if the amount is too large, it will be uneconomical and will have an unfavorable effect on the performance of the grout. For this reason, it is preferable to use the dispersant in an amount of 0.25 to 5.0 parts by weight per 100 parts by weight of the raw powder mixture.

Furthermore, in the present invention, aggregate is added to the raw material powder hardening agent mixture during granulation, if necessary, in order to make the treated ground high in strength.

The aggregates to be removed include Portland cement, blast furnace cement, alumina cement, colloid cement, magnesia cement, and early strength cement.

In addition to cements such as ultra-early strength cement, silica cement, and fly-assy cement, granulated blast furnace slag, sand, silicon dioxide, bentonite, and perlite.

Examples include silica balloons.

The amount of these aggregates to be used varies depending on the degree to which the strength of the treated ground is to be increased, but usually, adding 20 to 200 parts by weight to 100 parts by weight of the powdered curing agent mixture will provide a sufficient effect. is obtained.

In addition, since cements are hydraulic, when using them, it is desirable to use a setting retarder as appropriate or to use the hardening agent mixture of the present invention for construction without leaving it for a long time after granulation.

In the present invention, water is added to the curing agent mixture of the present invention produced in this manner at the time of construction to prepare liquid B consisting of a slurry of the curing agent. A suitable gel time retardant can be added to Solution B.

The types of gel time retardants used include one or two of phosphoric acid, monosodium hydrogen phosphate, disodium hydrogen phosphate, sodium phosphate, monopotassium hydrogen phosphate, dipotassium hydrogen phosphate, potassium phosphate, etc. These are mentioned above, and the gel time of the grout can be delayed as the amount of these used increases.

By using a gel time retardant in combination with a curing agent in this way, the method of the present invention can be applied to an infiltration injection method (a method in which grout injected into the ground is hardened within a gel time of several minutes or more), which is not possible with the instant setting method alone. It can also be applied.

Moreover, by using these gel time retardants, it is possible to preferably improve the strength of the treated soil.

In carrying out the present invention, the grout injection method into the ground is the same as the conventional method, and usually, before construction, a liquid A consisting of an aqueous solution of sodium silicate and an aqueous slurry B consisting of a hardening agent mixture of the present invention are prepared.
Mix equal volumes of each liquid and inject into the ground during construction.

In addition, when the present invention is applied to the instant bonding method, since the gel time of the grout is extremely short, the tip (ground injection part) of the grout, which is usually preferred in this type of construction method, is used. After a hollow double pipe equipped with a suitable mixer is installed in the ground, both liquids A and B are supplied separately into the pipe, and the mixture is mixed in the mixer at the tip and poured into the ground. Preferably by injection.

On the other hand, when applying the present invention to a general infiltration injection method, it is not necessarily necessary to adopt the injection method as described above, but instead use a normal Y-shaped pipe etc. to mix both liquids A and B into the ground. Can be injected.

According to the present invention, there is no risk of a situation occurring when performing the chemical injection method in a tunnel, shield, or other closed place, and the work can be carried out safely while expecting a non-polluting and safe chemical injection method. I can do it.

14- Next, the present invention will be explained with reference to examples.

Example (a) Component (slaked lime), Φ) component (dihydrate gypsum, β hemihydrate gypsum or ■-type anhydrite), setting retarder (sodium citrate or polypeptone), dispersant (sodium lignin sulfonate, β Sodium naphthalene sulfonate) and aggregate (colloidal cement, bentonite or sand), etc., were placed in a Narator (a mixer made by Seiyo Iron Works) in the proportions listed in Table 1, and after adding a specified amount of water, they were mixed for 20 minutes. A curing agent mixture of the present invention was produced.

Next, the obtained granulated product is subjected to impact pulverization: (1) as-is (a mixture of coarse particles and fine particles), (2) a granulated product sieved through a sieve (under the sieve), and (2) an O granulated product. 3 crushed by a machine
Two forms were used as test samples.

The manufacturing conditions are shown in Table 1.

Water was added to the curing agent mixture of the present invention obtained in Table 1 15-[■] to prepare liquid B for the chemical injection method.

Next, equal volumes of the obtained solution B and solution A consisting of a mixture of JIS No. 3 sodium silicate and water at a ratio of 1:1 (volume ratio) were mixed, and gel time and its cured product were added to the obtained grout. Unconfined compressive strength was measured.

Table 2 shows the mixing conditions for liquid B and the test results for grout.
4 parts by weight of monosodium hydrogen was added.

18- As is clear from Table 2, when water was added to the curing agent mixture of the present invention to prepare Solution B, no dust was observed to be generated at all.

In contrast, component (a), component (b), and a setting retarder.

When liquid B was prepared by mixing water with a powdered curing agent mixture obtained by simply mixing a dispersant, aggregate, etc., a large amount of dust was generated.

Patent applicant: Nitto Chemical Industry Co., Ltd. 19-

Claims (1)

[Claims] During construction, water is added to and mixed with the following mixture to prepare liquid B, and then liquid B and liquid A consisting of an aqueous sodium silicate solution are mixed and injected into the ground. .