Discrete Element Simulation Analysis of Time-dependent Deformation and Failure Mode of 2# Toppling Slope of a Hydropower Station

In order to thoroughly analyze the deformation and failure characteristics of toppling Slope, this work took the 2# toppling slope in the left bank of a hydropower station stilling basin as an example, the discrete element numerical simulation is carried out to analysis the time-dependent deformation and its deformation mechanism based on field survey, and the failure mode under the earthquake action or the current situation was also analyzed. The results are as follows. The deformation and failure of a slope is a progressive process from quantitative change to qualitative change, in this case, the unstable geological body will fail when progresses a certain degree, resulting in the displacement increase rapidly, and the displacement has some certain shock characteristics if triggered by earthquake. The previous or prometaphase deformation and failure of a toppling slope is dominated by the structure′s shear moving. With the gradually accumulated of tension effects, the deformation is mainly controlled by tensile rupture. Horizontal velocity and acceleration of the particle in slope have the elevation amplification effect under earthquake action, and the acceleration amplification coefficient is greater than the speed′s, and slope will get a big horizontal acceleration due to the acceleration effect of power wave and the release of elastic strain energy of rock mass when it destroys, which indicates the weak structural plane of rock mass controls the stability of rock slope. At present, 2# toppling slope is in a stable state as a whole, and its failure mode gives priority to the local collapse or the sliding along a small ridge on surface, but it may get entire failure when suffered from earthquake, in that case, the failure process should be the surface first to collapse and tumble, the slope shakes to loose, finally form a type of "sliding-tension" landslide.