Model test on the entrainment phenomenon and energy conversion mechanism of flow-like landslides

A reduced-scale physical model test with a scale of 1:2000 is designed based on the Wenjia Gully landslides. By changing the volume and kinetic energy of the sliding mass, we find that the material grading and bed-sediment thickness exert an important effect on the movement process of the landslide. To investigate the dependence of the entrainment on the grade of the sliding material and bed-sediment thickness, a series of comparison experiments with sliding masses of different grades and loose sediment bed materials of different thickness values are conducted. Furthermore, a high-speed camera is used to record the runout process. The experimental results indicate that because of the entrainment effect, the erosion depth of the substrate increases when the grade of the sliding mass increases. In addition, different characters appear in the erosion depth, volume of the accumulated area and entrainment length with the increase in bed-sediment thickness. Furthermore, the entrainment depth may increase when the bed-sediment thickness increases. The velocity of the sliding mass is reduced with the increase in basement thickness. Finally, based on the analysis of landslides and the previous experimental results, the energy conversion can be calculated to analyze the process of substrate entrainment for each sliding phase.