Influence of geometric parameters and elastic modulus on seismic dynamic response of rock slopes by IBEM#br#
BA Zhenning1，2，WU Mengtao1，2，LIANG Jianwen1，2
(1. Department of Civil Engineering，Tianjin University，Tianjin 300350，China；
2. Key Laboratory of Coast Civil Structure Safety，Ministry of Education，Tianjin University，Tianjin 300350，China)
Abstract：An indirect boundary element method for solving the dynamic response of slopes in layered half-space was proposed，and the influence of geometric parameters and elastic modulus on seismic effect of rock slopes was studied. The method simulates the scattered wave field generated by the slope topography by applying inclined and horizontal fictitious distributed loads on corresponding boundaries，avoiding the singularity problem in the conventional boundary element method and thus obtaining higher calculation accuracy and faster solution speed. The correctness and convergence of the developed method were analyzed，and the corresponding numerical calculations were carried out. Results show that the seismic dynamic response of rock slopes has significant elevation amplification effect，i. e.，the peak acceleration(PGA) amplification factor of the slope surface increases nonlinearly with increasing the relative elevation and the horizontal acceleration response is greater than the vertical. The ratios of the horizontal amplification factor to the vertical respectively corresponding to soft rock and hard rock can reach 1.51 and 1.14 in the calculation examples. The geometric parameters and elastic modulus of the slope have important influence on the dynamic response of the top of the slope. The PGA amplification factor increases with increasing the angle and height of the slope while attenuates with rising the elastic modulus. Comparisons indicate that the amplification factor calculated by the Code for Seismic Design of Buildings (GB50011—2010) does not take into account the influence of lithology and at the same time underestimates the topographic effect to some extent. According to the analysis results with different input seismic waves，an empirical formula for evaluating the dynamic response of the rock slope with the changes of geometric parameters and elastic modulus was proposed，which facilitates the quantitative description of research results. By analyzing the Fourier spectrum characteristics(of rock slopes such as peak value，shape and predominant frequency)，the spectrum law of dynamic response at the top with changing geometric parameters and elastic modulus was obtained，and then the spectral ratio curve was introduced to quantitatively evaluate the spectral amplification effect of ground motion with different angles，heights and shear wave velocities.
巴振宁1，2，吴孟桃1，2，梁建文1，2. 坡体几何参数与弹性模量对岩质斜坡地震动力响应的影响：IBEM求解[J]. 岩石力学与工程学报, 2019, 38(8): 1578-1592.
BA Zhenning1，2，WU Mengtao1，2，LIANG Jianwen1，2. Influence of geometric parameters and elastic modulus on seismic dynamic response of rock slopes by IBEM#br#. , 2019, 38(8): 1578-1592.
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2019, Vol. 38 
