Application of 3D-DDA integrated with unmanned aerial vehicle–laser scanner (UAV-LS) photogrammetry for stability analysis of a blocky rock mass slope

In stability analysis of discontinuity-controlled slopes, the rationality of results is related to the accuracy of three-dimensional (3D) slope morphology and the reliability of the discontinuity survey. With the advent of remote sensing technologies for engineering geological surveys and slope stability analyses, step-change increases have been made in the quality of data available and geometrical characterization of rock slopes. Although these techniques are frequently employed in the characterization of slope geometry and joint surfaces at present, limited research has been undertaken to effectively process the derived data and improve the quality in the reconstruction of slope geometry imported into 3D discontinuous numerical models. In this paper, an integrated system coupling 3D-DDA and UAV-LS photogrammetry is presented as a tool to evaluate the stability of a blocky rock mass slope. The system includes a UAV-LS module, a modeling module, a block-generation module, and a 3D-DDA calculation module. In the UAV-LS module, the use of UAV-LS system integrated with field mapping and site observations allows the acquisition of detailed outputs (point clouds) on both the slope and discontinuity geometry. An effective combination of commercial software Geomagic and Hyperworks is used in the modeling module to process oceans of 3D point cloud data and construct complex 3D geometrical models based on reverse engineering. In the block-generation module, the three-dimensional discontinuous deformation analysis (3D-DDA) method is then carried out in order to simulate the movement of potentially unstable blocks, within which an independent block-cutting algorithm is used to generate the blocks with arbitrary shapes and the finite structural planes similar to the real cases. The 3D-DDA calculation module uses 3D-DDA calculation algorithm to derive the simulation results. The capability of the proposed system for stability analysis of a jointed slope is demonstrated by a practical example.