PURPOSE: To obtain a single type of the title soln. which is rendered conformable to soil properties through free regulation of coagulation and consolidation time, by dropwise adding a CaCl2 soln. with a predetermined specific gravity to a sodium silicate soln. with a predetermined concn. in an amt. not exceeding a predetermined amt. every minute and agitating at a predetermined speed of rotation.

CONSTITUTION: The titled soln. is prepd. by dropwise adding a CaCl2 soln. with a specific gravity of 1.001W1.015 to a sodium silicate soln. with a concn. adjusted to 15W40° B'e in an amt. not exceeding 600cc per min and sufficiently agitating at a speed of rotation of 120W160r.p.m. so as to obtain a single type of mixed soln. Thus it is possible to prepare a single type of mixed soln. by mixing a sodium silicate soln. and a CaCl2 soln. which has hitherto bean impossible. In the use as a grout soln. for improvement and consolidation of soil, since the coagulation and consolidation time can be freely regulated, it is possible to apply the soln. to a varied type of soil. Further, there is an advantage that the chemical reaction in the soil can be rendered complete by sufficiently agitating the sodium silicate soln. and the CaCl2 soln. in a mixing tank prior to injection into soil.