Influence of the back pressure technique on the shear strength of soils

Abstract

A series of consolidated-undrained triaxial tests with pore pressure measurement were carried out to study the influence of the back pressure technique on the shear strength of soils. Hand-remolded samples of normally consolidated and overconsolidated kaolinite, compacted samples of kaolinite, hand-remolded normally consolidated black cotton soil, and hand-remolded and undisturbed samples of red earth were tested with and without the back pressure technique. The results indicate that a back pressure can significantly influence the shear strength and pore pressure response of soils. Two mechanisms govern the influence of the back pressure; which one applies depends on whether the soils compress or dilate during shear. The effective stress parameters are essentially unaffected by the back pressure technique. A partial consolidation technique promises to be an effective time-saving method of determining the shear strength parameters.