Stepped settlement: A possible mechanism for translational landslides

Translational landslides are a unique type of landslide that often causes disastrous consequences during their concealment. Based on the latest study and survey results, we discussed the cause of translational landslides and built a corresponding model. Then, the reliability of the genetic mechanism was validated via case studies. The results showed that higher water levels increase the total stress, thus leading to stepped settlement of the bedrock. The alternate assemblage of hard and soft layers causes large quantities of tension fissures and considerable settlement. This enormous settlement produces larger gravitational potential energies and impact energies and leads to the generation of pull rift troughs. In addition, a large number of landslides occurred with relatively moderate amounts of rainfall. The increasing total stress on the sill caused by the reservoir water level and the heavy rainfall represents the spatiotemporal difference in the stepped settlement of bedrock, which is one of the main reasons for atypical landslides. Therefore, analyses of the failure mechanism and safety evaluations of translational landslides in reservoir areas should focus on their special engineering geological information such as the sliding bed with distributed soft and hard strata.