Simulation of spatially variable underground seismic motions in circular-arc canyons with horizontally-layered inhomogeneous medium
Received:October 08, 2017  Revised:December 27, 2017
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DOI:10.7511/jslx20171008001
KeyWord:coherence function  multi-layered circular-arc canyon  topographic effect  transfer function  underground multi-point earthquake motion
        
AuthorInstitution
柳国环 天津大学 建筑工程学院, 天津
马杰 天津大学 建筑工程学院, 天津
冯啸 天津大学 建筑工程学院, 天津
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Abstract:
      In this paper,a visual program for simulating spatially variable underground seismic motions in circular-arc canyons taking the horizontally-layered effect into account is developed,and the reliability of the program is verified.Firstly,the frequency-domain solution for the scattering of SH waves by a circular arc considering horizontally-layered effect is described.The essence of it is to break through traditional theoretical limitations of homogeneous medium and canyons do not pass through multi-layer soil.Secondly,a two-step transfer function method combining the transferring from flat-ground terrain to the canyon surface (step one) with the transferring from the canyon surface to underground location (step two) is adopted to derive the underground target PSD and response spectrum of circular-arc canyons.And then,the coherence function taking account of the flat-concave correlation of circular-arc field and its derivation are described in detail.Finally,aiming to provide convenience for further development and application of the simulation theory above,a program for simulating underground seismic motions in circular-arc canyons taking account of horizontally-layered effect is developed and the comparison between simulated and target results including PSD,response spectrum and coherence coefficient is given,which further verifies the rationality and reliability of the method.