To solve seismic wave scattering by a large-scale three-dimensional(3-D) hill topography, a fast parallel indirect boundary element method(IBEM) is developed by proposing a new construction method for the wave field, ...To solve seismic wave scattering by a large-scale three-dimensional(3-D) hill topography, a fast parallel indirect boundary element method(IBEM) is developed by proposing a new construction method for the wave field, modifying the generalized minimum residual(GMRES) algorithm and constructing an Open MP plus MPI parallel model. The validations of accuracy and efficiency show that this method can solve 3-D seismic response of a large-scale hill topography for broadband waves, and overcome the weakness of large storage and low efficiency of the traditional IBEM. Based on this new algorithm architecture, taking the broadband scattering of plane SV waves by a large-scale Gaussian-shaped hill of thousands-meters height as an example, the influence of several important parameters is investigated, including the incident frequency, the incident angle and the height-width and length-width ratio of the hill. The numerical results illustrate that the amplification effect on the ground motion by a near-hemispherical hill is more significant than the narrow hill. For low-frequency waves, the scattering effect of the higher hill is more pronounced, and there is only a single peak near the top of the hill. However, for high-frequency waves, rapid spatial variation of displacement amplitude appears on the hill surface.展开更多
A two and a half dimensional(2.5D)multi-domain indirect boundary element method(IBEM)is developed to study the wave scattering of obliquely incident P-,SV-and SH-waves by a hill-valley staggered topography in a multi-...A two and a half dimensional(2.5D)multi-domain indirect boundary element method(IBEM)is developed to study the wave scattering of obliquely incident P-,SV-and SH-waves by a hill-valley staggered topography in a multi-layered half-space.The IBEM algorithm includes using 2.5D full-space and half-space Green’s functions to construct scattered fields in decomposed closed and opened half-space regions,respectively,and using the dynamic stiffness method to solve the free fields.All regions are finally integrated by introducing the compatibility conditions to obtain the total wave fields.The proposed 2.5D IBEM has the flexibility in dealing with complex boundaries by directly applying the fictitious loads on the regions’boundaries,with a less storage requirement compared to the full 3D models.Besides,by combining the specific advantages of the two kinds of Green’s functions,the method is well suitable for handling coupled topographies with high accuracy.The method is validated by comparison with published results for a single valley as well as a single hill topography.The effects of height-to-width ratio of hill and layering on dynamic responses are further parametrically investigated by numerical implementations in frequency domain.Results show that the interaction between valley and hills can lead to a more significant amplification within the valley region,and dynamic responses are deeply influenced by the height-to-width of hill,simultaneously depending on incident angle and frequency.Besides,the site effects become more complex when the stratification feature is taken into account.展开更多
基金National Natural Science Foundation of China under Grant No. 51678390National Natural Science Foundation of China under Grant No. 51708391the Major Science and Technology Projects in Tianjin under Grant No. 18ZXAQSF00110。
文摘To solve seismic wave scattering by a large-scale three-dimensional(3-D) hill topography, a fast parallel indirect boundary element method(IBEM) is developed by proposing a new construction method for the wave field, modifying the generalized minimum residual(GMRES) algorithm and constructing an Open MP plus MPI parallel model. The validations of accuracy and efficiency show that this method can solve 3-D seismic response of a large-scale hill topography for broadband waves, and overcome the weakness of large storage and low efficiency of the traditional IBEM. Based on this new algorithm architecture, taking the broadband scattering of plane SV waves by a large-scale Gaussian-shaped hill of thousands-meters height as an example, the influence of several important parameters is investigated, including the incident frequency, the incident angle and the height-width and length-width ratio of the hill. The numerical results illustrate that the amplification effect on the ground motion by a near-hemispherical hill is more significant than the narrow hill. For low-frequency waves, the scattering effect of the higher hill is more pronounced, and there is only a single peak near the top of the hill. However, for high-frequency waves, rapid spatial variation of displacement amplitude appears on the hill surface.
文摘A two and a half dimensional(2.5D)multi-domain indirect boundary element method(IBEM)is developed to study the wave scattering of obliquely incident P-,SV-and SH-waves by a hill-valley staggered topography in a multi-layered half-space.The IBEM algorithm includes using 2.5D full-space and half-space Green’s functions to construct scattered fields in decomposed closed and opened half-space regions,respectively,and using the dynamic stiffness method to solve the free fields.All regions are finally integrated by introducing the compatibility conditions to obtain the total wave fields.The proposed 2.5D IBEM has the flexibility in dealing with complex boundaries by directly applying the fictitious loads on the regions’boundaries,with a less storage requirement compared to the full 3D models.Besides,by combining the specific advantages of the two kinds of Green’s functions,the method is well suitable for handling coupled topographies with high accuracy.The method is validated by comparison with published results for a single valley as well as a single hill topography.The effects of height-to-width ratio of hill and layering on dynamic responses are further parametrically investigated by numerical implementations in frequency domain.Results show that the interaction between valley and hills can lead to a more significant amplification within the valley region,and dynamic responses are deeply influenced by the height-to-width of hill,simultaneously depending on incident angle and frequency.Besides,the site effects become more complex when the stratification feature is taken into account.
