Experimental study on the effect of particle size on the shear characteristics of large-displacement soil exposed to heat treatment: Shear fluctuation and heat degradation

Abstract

The shear characteristics of soil on the basal face of a landslide body have important implications on landslide dynamics. In this study, ring-shear tests were carried out on quartz sand to study the shear characteristics of soil particle materials on the basal facies. Quartz sand samples of different particle sizes (0.25–1 mm) were treated at high temperature (20–800 °C) to determine the influence of temperature and particle size distribution (PSD) on their shear characteristics at different shear speeds. The shear characteristics of the samples were analyzed, including the shear stress, shear stress fluctuation, density variation, and degree of fragmentation. The results show that the amplitude of shear stress fluctuation increases with increasing shear velocity. It can be determined that the smaller the particle size, the greater the residual shear strength. Elevated temperature has a certain influence on the quartz sand and the shear characteristics (e.g., shear stress) exhibit a low degree of deterioration. The dilatancy and compaction mechanism of the samples under large displacement shearing is further discussed.