Mobility Character Of Earthquake-Induced Rockfall

Rockfall is a common geologic disaster in the mountain area of southwest China, causing a huge amount of losses in lives and properties. Earthquake-induced rockfall is a catastrophe pronounced in both scale and number. The motion characteristic of the earthquake-induced rockfall is still lack of investigation even though it should be one of the main reasons that triggers the catastrophe.A series of shaking table tests are conducted to investigate the motion characteristics of the earthquake-induced rockfall. The results show that:(1) when subjected to seismic loading, the rockfall exhibits stronger bouncing ability with a larger magnitude of the amplitude; the horizontal displacement is increased to a maximum of 48%, whilst the lateral displacement demonstrates an increase up to 152%. (2) The rockfall with more angularity shows stronger bouncing ability than its counterpart with less angularity, and the proportion of bounce is relatively larger. The horizontal and lateral displacements increase corresponding to the shape of triangular prism, quadrangular prism, pentagonal prism and hexagonal prism, respectively. The maximum horizontal displacement of the hexagonal prism is 1.63 times that of the triangular prism, whilst the maximum lateral displacement of the hexagonal prism is 3.99 times that of the triangular prism. (3) The influence of frequency on the horizontal and lateral displacements is not obvious. The reason can be the coupling of the frequency and impact force of the collision, (4) The rockfall with a larger magnitude of slenderness-ratio inclines to rotate. The horizontal and lateral displacements decrease with an increase in the slenderness-ratio. (5) The horizontal and lateral displacements are mainly influenced by the shape of the rockfall, amplitude and frenquency.Numerical simulations based on the Discontinuous Deformation Analysis (DDA) method are performed and the model developed is validated by the experimental results. A case study with EICentro and Kumamoto earthquake wave applied is shown. It is concluded that the horizontal displacement increases to a maximum of 40% when subjected to seismic loading. The horizontal displacement is in relation to the slope angle, increasing with an increase in the slope angle. In addition, with respect to the pragmatic perish rock, a DDA model with Qingping earthquake wave is developed to analyze the failure process and motion characteristics of the collapse. The results show that the motion characteristics are high influenced by the direction of applying seismic loading. The horizontal displacement may be more significantly affected with the seismic loading applied vertically than that applied horizontally.