The study on rock thermal fractures at sliding surface of Jiweishan landslide

High temperatures lead to thermal fracture in the rock, which can greatly impair the rock's mechanical properties. During Jiweishan landslide, rocks on the sliding surface generate high temperatures due to frictional heating. Studies on thermal fracture during landslides and its influence on the sliding process are unclear. Here we use thermogravimetry and dilatometry to study the thermal expansion and thermal fracture of the rocks at the base of the 2009 Jiweishan landslide. Experimental results show that rocks generate a large number of thermal fractures and thermal expansion while reaching temperatures of up to 827.3 & nbsp;C. The generation of CO2 gas also significantly produces and promotes thermal fractures. This indicates that the rapid heating process during the Jiweishan landslide could have caused thermal fractures on the sliding surface during the landslide, which could have then weakened the mechanical properties of the rock, making the sliding surface more susceptible to entrainment. As a result, the sliding surface lost frictional resistance during the landslide, resulting in a faster sliding velocity and a longer sliding distance. In addition, we infer that thermal fracture is beneficial for CO2 gas to be released from the rock and enter the sliding zone, which may produce pore pressure, reduce the effective normal stress on the sliding surface, and which also contributes to the lubrication.