ON THE SHEAR STIFFNESS DECREASE OF SANDY SOILS DUE TO PARTICLE CRUSHING PROGRESS

Abstract

Many previous studies have focused on theoretical and experimental evaluations of the crushing of sandy soil particles under high pressure conditions. From the perspective of practical scenarios, the decreased bearing capacity caused by volume shrinkage and the reduced shear strength and stiffness caused by the crushing of sandy soil particles are important aspects. Therefore, this study aims to confirm the decrease in the shear stiffness of sandy soils subjected to various stress levels combined with high principal stresses. Author conducted crushing tests using the high-pressure true tri-axial compression apparatus under the planned stress paths. Tests on isotropic compression without deviatoric stress q and those involving combinations of the mean stress p and deviatoric stress q up to the shear failure line (SFL) on the p-q plane are employed to characterize the particle crushing of sandy soils. The results indicate that the shear stiffness of sandy soils starts to decrease due to particle crushing under a combination of low mean stress p and high deviatoric stress q. Furthermore, experimental formulas regarding the decrease in shear stiffness due to particle crushing were estimated based on the relationships among the mean stress p, deviatoric stress q and deviatoric strain εd.