Chemical grout for ground injection and method for accretion
AssigneeNissan Chemical Industries, Ltd.
InventorsYoshitane Watanabe, Eiji Okumura, Mikio Ando
Life of this patent
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Abstract
A chemical grout for ground injection which is prepared by incorporating from 0.1 to 4.5 parts by weight of sulfamic acid and from 0.2 to 10.0 parts by weight of a water soluble magnesium salt into 100 parts by weight of an aqueous sol having a pH of 8 to 10.5 and containing from 5 to 25% by weight of colloidal silica (as SiO.sub.2) having a particle size of 3 to 7 m.mu., and from 0.05 to 1.5% by weight of Na.sub.2 O. This injecting grout has a gelation time not longer than 300 minutes. Soft ground can be consolidated by using the grout.
Claims15
A chemical grout for ground injection, comprising:
- an aqueous sol having an original pH of 8 to 10.5, said aqueous sol comprising (a) 5 to 25% by weight of colloidal SiO.sub.2 having a particle size of 3 to 7 m.mu., (b) 0.05to 1.5% by weight of Na.sub.2 O and (c) water;
- 0.1 to 4.5 parts by weight of sulfamic acid per 100 parts by weight of said aqueous sol;
- and
- 0. 2 to 10.0 parts by weight of a water soluble magnesium salt selected from the group consisting of magnesium sulfamate, magnesium sulfate and a mixture thereof per 100 parts by weight of said aqueous sol.
A method for strengthening soft ground, comprising injecting into said ground a chemical grout comprising:
- an aqueous sol having an original pH of 8 to 10.5, said aqueous sol comprising (a) 5to 25% by weight of colloidal SiO.sub.2 having a particle size of 3 to 7 m.mu., (b) 0.05to 1.5% by weight of Na.sub.2 O and (c) water;
- 0.1 to 4.5 parts by weight of sulfamic acid per 100 parts by weight of said aqueous sol;
- and
- 0.2 to 10.0 parts by weight of a water soluble magnesium salt selected from the group consisting of magnesium sulfamate, magnesium sulfate and a mixture thereof per 100 parts by weight of said aqueous sol.
A method of making a chemical grout for ground injection, comprising adding (a) 0.1 to 4.5 parts by weight of sulfamic acid and 0.2 to 10.0 parts by weight of a water soluble magnesium salt selected from the group consisting of magnesium sulfamate, magnesium sulfate and a mixture thereof to (b) 100 parts by weight of an aqueous sol having a pH of 8 to 10.5 and comprising 5to 25% by weight of colloidal SiO.sub.2 having a particle size of 3 to 7 m.mu. and 0.05to 1.5% by weight of Na.sub.2 O and water.
Dependencies are inferred from the claim text.