Determination of soil strength parameters from unconfined compression testing on partially saturated soils

Abstract

The uneonfined compression test is used in most geotechnical studies to y -determine soil strength parameters. This test is recommended for fine cohesive > ^ soils with a degree of saturation of more than 90%. It has been observed that jj, ^ such conditions, especially the latter, seldom occur and the shear strength of | 0 partially saturated soils is underestimated when a null friction component (<j>=0°) and a cohesion value equal to half the axial compression stress at * £ failure are assumed (c= /i qj. Mathematical expressions are determined in this article in order to determine both the value of the internal friction angle "(J)" and that of cohesion "c" from the Mohr's circle corresponding to the stress conditions of the unconflned test, a comparative analysis of slope stability is carried out for both cohesive soils and soils with cohesion and friction.