Laboratory investigation into the monotonic and cyclic behaviour of a clean sand stabilised with colloidal silica

Abstract

This paper presents a laboratory investigation into passive stabilisation of liquefiable sands by means of colloidal silica (CS). In order to examine the improvement of the mechanical behaviour of liquefiable sands stabilised with CS, an extensive laboratory testing programme comprising unconfined compressive strength and Brazilian tensile strength tests, as well as undrained monotonic and cyclic triaxial tests, was performed on a clean quartz sand treated with CS. The test results are compared to the corresponding results for the untreated sand. The effects of CS concentration, curing time, density and confining stress on the monotonic and cyclic response of the treated sand are examined, among others. It is shown that stabilisation of the tested sand with CS significantly improves both the undrained monotonic and cyclic strength. The influence of CS concentration on the monotonic response is reduced with increasing mean effective stress. Cyclic resistance, however, is shown to be practically unaffected by CS concentration. Furthermore, cyclic straining at 5 to 10% of double-amplitude axial strain does not influence the undrained shear strength of the stabilised sand.