JPS5935952B2 - How to strengthen soil - Google Patents

Description

[Detailed Description of the Invention] The so-called grouting method, which strengthens the ground by injecting water glass and a hardening agent into the soil, is used in road construction, tunnel engineering, etc.

However, in such construction methods, there is a method in which water glass and a hardening agent are mixed in advance and the mixed solution is injected (1 shot method or 1.5 shot method), and a method in which water glass and hardening agent are separately injected ( However, in order to evenly mix the water glass and hardening agent and evenly diffuse the chemical into the soil, the one-shot method is used to further enhance the soil strengthening effect. It is desirable to slowly inject over a wide area at the slowest possible speed and over a long period of time. When adopting such an injection method, it is necessary that gelation does not occur for about 30 minutes or more after mixing the water glass and the hardening agent, but a dialkyl dibasic acid is a hardening agent that satisfies this requirement. Esther has been attracting a lot of attention lately. However, since the dialkyl ester is poorly soluble in water, it is very difficult to uniformly disperse it with water glass, and as a result, it is difficult to obtain uniform gel strength, that is, high gel strength, which is not necessarily satisfactory in practical terms. .

Furthermore, there are problems in terms of on-site work efficiency when preparing grouting chemicals, such as the need for a powerful stirrer to prepare a uniform solution with water glass. However, as a result of extensive research in order to solve this problem, the present inventors discovered that the general formula RIOOC (CH2) was used as a hardening agent for water glass.
When using a dibasic acid ester represented by nCOOR2 (R1, R2, and n are the same as above), since the ester is water-soluble, it must be easy to mix uniformly with water glass, and the mixture must be mixed with soil. There is virtually no risk of thickening or gelation within the time it takes to finish pouring into the soil, and once gelation occurs once it is poured into the soil, it has extremely strong soil consolidation properties. The present inventors have discovered that the present invention can be achieved by discovering that the soil can be strengthened very efficiently because of the above properties.

The curing agent used in the present invention is a dibasic acid ester represented by the above general formula, where R1 is an alkyl group having 1 to 4 carbon atoms, ie, a methyl group, an ethyl group, a propyl group, a butyl group, or a hydroxyalkyl group. In the case of an alkyl group having 5 or more carbon atoms, the water solubility of the curing agent decreases, making it difficult to obtain strong consolidation strength.

Furthermore, the effects of the present invention can be fully achieved regardless of whether R1 or R2 are hydroxyalkyl groups. Examples of such hydroxyalkyl groups include hydroxymethyl group (-CH2), α-hydroxyethyl group (-CH-CH
3), β-hydroxyethyl group (-CH2-CH2),
β-hydroxypropyl group (-CH2・CH-CH3
), γ-human (-CH2.CH-CH2), and the like.

Further, n is required to be an integer of 3 or more, and esters such as malonic acid, succinic acid, glutaric acid, adipic acid, and pimelic acid are used. Esters particularly preferably used in the present invention include methyl glutarate/hydroxyethyl ester, methyl glutarate/β-hydroxy-γ-methoxypropyl ester, methyl succinate/β-hydroxy-γ-methoxypropyl ester, and succinic acid. ethyl. β-hydroxy-γ-methoxypropyl ester, butyl adipate/hydroxyethyl ester, methyl adipate/hydroxyethyl ester, glutaric acid di-
Examples include hydroxyethyl ester, succinic acid diβ-hydroxy-γ-methoxypropyl ester, and the like. These esters can be used not only alone but also in combination. Such esters usually have an alkyl group having 1 to 4 carbon atoms.
It is produced by substituting one or two alkyl groups of a dibasic acid dialkyl ester with ethylene glycol, glycerin, etc. in a transesterification reaction. In the present invention, the desired dibasic acid ester may be isolated from the reaction solution obtained by such a reaction and used as a curing agent, but there is no practical problem even if the reaction solution is used as it is as a curing agent. Economically, it is advantageous to use the reaction crude liquid as it is. In carrying out the method of the present invention, usually,
All you have to do is mix water, water glass, and hardener and inject it into the soil. It is appropriate to adjust the amounts of these agents so that the water glass is 20 to 50% by weight and the curing agent is 2 to 10% by weight based on the entire mixture. When preparing such a mixed solution, curing aids such as sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, and sodium bicarbonate, hardening agents such as calcium chloride, sodium aluminate, glyoxal, ethylene glycol monoacetate, and ethylene glycol diacetate, silicone, etc. Of course, a small amount of an antifoaming agent, cement, bentonite, surfactant, or fluidizing agent may be added. The method of the present invention is used for the purpose of increasing the strength of the ground and rock, preventing water leaks and springs, and preventing collapse, such as roads, dams, tunnels, etc.
It can be effectively adopted for subway, sewerage, construction work, etc.

Next, the method of the present invention will be explained in more detail by giving examples.

Examples 1 to 7 Dibasic acid esters shown in Table 1, No. 3 water glass, and water were mixed in predetermined amounts, and the dissolution state of the esters and the gelation time of the mixed liquid were measured.

Further, pour the mixture into a 5 mm diameter tube. It was poured into a small mold with a height of 10 cnL and left to stand, and the compressive strength of the obtained solidified body was measured after 24 hours using a uniaxial compression tester. These results are shown in Table 1. Control Examples 1 to 3 Experiments were carried out in accordance with the Examples, except that known dibasic acid dialkyl esters were used in place of the esters in the Examples.

Claims (1)

[Claims] 1 Water glass and general formula R_1OOC(CH_2)nCO
A dibasic acid ester represented by OR_2 [wherein R_1 is an alkyl group or hydroxyalkyl group having 1 to 4 carbon atoms, R_2 is a hydroxyalkyl group and n is an integer of 3 or more] is injected into the soil. How to strengthen soil.