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 SiO2) having a particle size of 3 to 7m mu , and from 0.05 to 1.5% by weight of Na2O. This injecting grout has a gelation time not longer than 300 minutes. Soft ground can be consolidated by using the grout.
