Effect of bedrock-surface inclination on characteristics of trailing edge crack in soil landslide sliding along the bedrock surface

The position of the trailing edge crack is often the location of the boundary of the trailing edge in a soil landslide. This paper aims to explore the effect of bedrock-surface inclination on the characteristics of the trailing edge crack in a soil landslide sliding along the bedrock surface. Twelve laboratory tests on trailing edge cracks in soil landslides along the bedrock surface are first conducted. A theoretical approach for calculating the position of the trailing edge crack is then proposed. The theoretical approach is finally applied to calculate the positions of trailing edge cracks in twelve laboratory landslides and two field landslides. The results show that the inclinations of the trailing edge cracks in the twelve laboratory tests range from 63.7° to 78.1°. As the bedrock-surface inclination increases，the failure mode of the trailing edge crack transitions from predominantly tensile failure to predominantly shear failure，resulting in a corresponding decrease in the inclination of the trailing edge crack. The proposed theoretical approach treats the landslide as a stressed body，with the slip surface divided into two parts：the bottom slip surface and the steeper trailing edge crack surface. The bottom slip surface exhibits shear failure. In contrast，the trailing edge crack surface exhibits tensile failure and shear failure at positions near and far from the slope surface，respectively. For both laboratory and field landslides，the overall deviation of the trailing edge crack positions calculated by the theoretical approach from the measured positions is not significant. The results of this study help to accurately locate the trailing edge crack in the landslide.