关键词: 斜坡, 岩性, 岩体结构, 天然波, 正弦波, 加速度响应

Abstract: Lithology and rock structure of a rock slope are two of the most important controlling factors on its deformation and failure process during earthquake. Four shaking table models of slopes are designed to explore the effects of the above two factors on slope seismic responses. Referring to lithology, hard rock with high strength and soft rock with low strength are modeled, at the same time, an isotropic slope and a horizontally layered slope are selected for each kind of lithology. Based on a large number of sensor recordings, results are analyzed under excitations of both the real waves and sine waves which have the similar predominant frequency. The main conclusions are drawn as follows: (1) The horizontal accelerations on the slope surface and inside the slope demonstrate topographic amplification effect for all the 4 model slopes; and the maximum amplification factor occuring at the crest of the soft rock slope model; (2) The topographic effects in soft rock slopes are stronger than those in hard rock slopes, which is more obvious in the two isotropic rock slopes, and the topographic effect in the isotropic and soft rock slope depict nonlinear change laws. (3) When the shaking direction accords with the horizontal structure surface just as in the present study, the layered slopes demonstrate stronger topographic amplification effect for horizontal accelerations, especially in soft rock slopes; (4) Lithology plays a more important role in topographic effect than discontinuity in a rock slope during earthquake. The results provide a reference for the seismic design of rock slopes.

Key words: slope, lithology, rock structure, real waves, sine waves, acceleration responses