Temperature Evolution in Sandy Soil Under Large-Displacement Shear

Abstract

Granular material within the sliding zone of a landslide can undergo large-displacement shearing during its motion. The mechanical behaviour of the material under such shear process significantly affects the basal friction of a landslide and therefore governs its mobility. Both field observations and laboratory experiments have provided evidence that this shear process is companied by significant temperature generation. The generated heat can dynamically modify the shear strength of the material by degrading organic matter or influencing pore pressure. Although the effects of shear-induced temperature rise have been discussed in previous studies, it remains difficult to directly record the temperature evolution during large-displacement shearing. In this study, a direct temperature measurement unit integrated with a ring-shear apparatus is developed to record the complete temperature evolution process, from heating to cooling. Ring-shear tests were conducted on silica sand samples with two different grain sizes. The results indicate that the temperature evolution curve exhibits an initial increase followed by a steady rising phase once the specimen reaches the critical state. With continued shearing, the temperature generation rate gradually decreases, which is attributed to grain crushing occurring within the shear zone. The measurements further reveal a pronounced spatial heterogeneity in temperature distribution along the shear zone, with the temperature at the centre being approximately four times higher than that near the boundary. These obtained data are expected to be valuable for calibrating parameters in thermal-mechanically coupled numerical analyses of landslide dynamics.