Volume 2, Issue 4 (December 1979)
Strength and Stiffness of Silicate Grouted Sand with Different Stress Histories
The effects of stress history and relative density on the short-term strength and stiffness of a granular soil (Ottawa 20–30 sand) that was chemically stabilized with a sodium silicate grout, a solution of hydrated sodium silicate, water, ethyl acetate, and formamide, were investigated. A system was developed to inject grout into sand specimens that were prepared in a triaxial cell; the specimens were subjected to a confining stress of 360 kPa and grouted under a pressure of 144 kPa. The results are analyzed in terms of Mohr-Coulomb failure theory, and comparisons are made among the compressive strength, initial tangent modulus, angle of internal friction, and cohesion of the specimens for different test conditions.
The strength of the specimens grouted under a confining stress is seen to be a function primarily of their relative density. Little difference in mechanical behavior was observed between specimens grouted under a confining stress and those grouted under at-rest conditions. The angle of internal friction of grouted specimens with a low or high relative density differed only slightly from that of ungrouted specimens with a low or high relative density. However, the compressive strength of loose and dense grouted specimens increases relative to that of ungrouted specimens because of an increase in the cohesion, although the initial tangent modulus of loose and dense grouted specimens is similar to that of dense ungrouted specimens.