A Thermo-Poro-Mechanics Model Predicts the Transition from Creep to Rapid Movement of Large Landslides

Risks associated with large landslides pose a severe threat to human life and property. Hence, the creep phase, the signal before the occurrence of large landslides, plays a significant role in the safety of mountainous areas. However, the mechanism of movement in the creep phase remains unclear. In this study, landslide events were divided into six blocks based on a thermo-poro-mechanical model. Blocks represent different landslide areas, which cannot be viewed collectively because of their varying external environments or intrinsic properties. We found that the phases of movement (stationary, creep, and rapid) of different blocks differed. Dividing the landslide into blocks may compensate for the disadvantage that a single sliding body model cannot reflect local creep. Additionally, friction strengthening and weakening were considered in this model. Friction strengthening refers to the phenomenon in which the friction coefficient increases with velocity, whereas friction weakening refers to the phenomenon in which the friction coefficient decreases with velocity. In this study, friction strengthening and weakening occurred before and after the critical velocity, respectively. Our findings suggest that the rapid movement of a landslide is mainly affected by the friction-weakening stage and the thermal-pressure generation stage. Furthermore, the former has a more profound influence than the latter. Notably, this model shows that the creep phase is controlled by friction strengthening. This study is expected to stimulate new ideas for landslide prediction.