Seismic input method coupling ground motion and fault dislocation for near-fault engineering sites
Accurate seismic response analysis of near-fault engineering sites requires precise coupling loads of ground motion and fault dislocation.However,current studies tend to rely on excessive assumptions about fault movement behavior,leading to a failure in accurately representing the coupled effects of seismic activity and fault slip.To address this issue,this paper proposes a seismic input method considering the coupling of ground motion and fault slip in the near-fault engineering sites.Firstly,the seismic source scale global domain is divided into the internal domain where the engineering site is located,and the external domain beyond the site.Secondly,the seismic wave field is obtained at the source scale through the kinematic source model.Subsequently,an Extended Domain Reduction Method(XDRM)is established for models featuring non-continuous internal domains with active faults.This method transforms the seismic wave field propagating to the internal domain into dynamic loads,which are then applied to the fault boundaries and internal truncation boundaries.This achieves the seismic response analysis of near-fault engineering sites under the coupled effects of ground motion and fault dislocation.Finally,three topographical scenarios—flat terrain,mountainous terrain,and valley terrain—are designed to validate the reliability of this method.Results indicate that The XDRM calculation results exhibit a good agreement with the kinematic source model,demonstrating high accuracy.Moreover,the proposed method can effectively capture the coupling distribution features of ground motion and fault dislocation,as well as near-fault effects,including velocity pulses,hanging-wall effects,and vertical effects.Through the analysis and comparison of seismic responses in different terrain features,the broad applicability of the proposed method has been validated.This can provide a scientific basis for seismic design analysis in practical engineering.
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