Effect of Loading Path on the Mechanical Properties of Completely Decomposed Granite Soil Based on the Multiscale Method

Mechanical properties of intact completely decomposed granite (CDG) soil, widely distributed in South China, decrease drastically as encountering external load-related disturbance or soaked by water. In this study, staged triaxial consolidated drained (CD) test and microscopic scanning were conducted using intact CDG specimens extracted from a construction site to investigate the mechanical behavior and microscopic pore distribution. The results show that the stress-strain relationship reveals a shrinking behavior in the first-stage loading and a brittle behavior in the second-stage loading. The development of cracks is affected by the principal stress, which causes the pores and cracks to shrink or partially close. In addition, Esec-1 increases linearly with the increase of confining pressure, but Esec-2 decreases exponentially.