Stability analysis of complex terrain slope based on multi-source point cloud fusion

Numerical modelling is a common routine for slope stability analysis in the complex terrain, and the accuracy of topographic survey has a great impact on the results. In this study, a combination of unmanned aerial vehicle (UAV) photogrammetry and 3D laser scanning technique was first proposed to establish a high-precision digital elevation model (DEM), which could be accurate to 0.2 m, fulfilling the engineering requirements. Then, a series of 3D/2D finite element models (FEM) were constituted on the basis of DEM to investigate the slope stability in the complex terrain. The results indicate that the deformation of complex terrain slope is chiefly triggered by compression-shear failure and the failure zones are mostly distributed on the middle-upper part and the scarp. Furthermore, the complex terrain slope is divided into concave, convex, concave-convex and convex-concave slope according to the topographical curvature, and the factor of safety (FOS) is as follows: the maximum value 1.8504 for the concave-convex slope, the minimum value 1.1129 for the convex-concave slope, and the median for either concave or convex slope. The inflection points and curvature of the slope jointly determine the shape of nonlinear slope, dominating the morphological effect on the slope stability, so the rational use of section morphological effect will be conducive to the overall stability of the slope. For four representative slopes, the plastic deformation first emerges into the middle, then progressively develops to the upper, and finally forms the connected failure zones.