EXPERIMENTAL STUDY ON RELATIONSHIP BETWEEN STRUCTURAL CHARACTERISTICS OF LOOSE SOIL SLOPE AND ACCUMULATION CHARACTERISTICS OF LANDSLIDE DAM

According to physical model tests,we discuss the dynamic process and accumulation characteristics of landslide dams formed under three different slope features including uniform slope(slope compositions mixed uniformly,parallel slope(soil layer surface parallel to the sliding surface) and intersecting slope(soil layer surface intersecting with the sliding surface). The material distribution and morphological characteristics of the landslide dams are studied by sub-regional sampling and 3D scanning technology. The results demonstrate that the accumulation characteristics of landslide dam are closely related with the slope body. The material distribution in the longitudinal direction(along the main river) and cross-sectional direction(along the sliding direction) of the dam are basically corresponded with that of the slope body,but different in vertical direction due to the differences in dynamic process and accumulation mechanism of the landslide dam under different slope conditions. The uniform slope and parallel slopes are initiated in an overall-starting mode. Obvious vertical infiltration effect and material exchange are present during the movement process,leading to the inverse grading distribution of sediment in the vertical direction of the dams. And the cross-sectional shapes of the dam are mostly flat and inclined. The intersecting slopes present a layered-starting mode. The original sequences are maintained during the movement and accumulation process. The pushing-climbing effect and horizontal infiltration can occur under some conditions,accounting for the inverse grading characteristic of sediment distribution in the vertical direction and undulating cross-sectional shape of the dam. This study promotes a better understanding of the relationship between slope body and landslide dam and provides a basis for rapid assessment of the stability of landslide dam and restoration of the initial state of the slope.