Experimental Study on Meso-Mechanical Behavior of Coarse-Grained Granular Soils

Granular-soils are widely distributed geomaterials in nature which significantly encounter geohazards as landslides and debris flows. The assessment of meso-mechanical behaviours of such geomaterials is quite complex due to the existence of varying conditions of soil compositions. In this study, the soil samples from Yunnan province of China are considered for triaxial tests under different consolidated drained and undrained (saturated and unsaturated) conditions with varying confining stresses. The extensive experimental investigation revealed that different consolidation and draining conditions significantly influence the meso-mechanical behaviour of granular-soils. The results show that the shear strength parameters decrease under different conditions, such as CD (unsaturated), CD (saturated) and CU (consolidated undrained), respectively. The stress–strain mechanism of samples under both CD (saturated and unsaturated) showed an obvious hardening behaviour with no peak stress while strain-softening behavior in CU (consolidated undrained) condition. Furthermore, the Mohr–Coulomb relationship is suggested to obtain and compare the p-q linear relationships of shear strength parameters under different conditions. The present study paved the way towards new insights into meso-mechanical behaviour and deformation characteristics in granular-soils existing in nature.