摘要
在TI场地平面外动力刚度矩阵的基础上,推导出斜线均布荷载动力格林函数,进而以该格林函数为基本解建立间接边界元方法求解了沉积谷地对平面SH波的散射问题。文中验证了方法的正确性,并分别将沉积内部和外部介质考虑为TI介质,在频域和时域内进行了计算分析。研究表明:沉积TI参数的改变主要导致了沉积自身动力特性的改变,进而使得沉积表面位移幅值放大谱的峰值频率和谱值均发生明显改变;半空间TI参数的改变则导致了各方向上半空间与沉积阻抗比的改变,因而对放大谱的峰值频率影响较小,其影响主要体现在峰值大小上;另外,通过求解Ricker波输入下沉积附近观测点的位移幅值时程发现,沉积和半空间的TI参数亦对弹性波在含沉积半空间中的传播有着显著影响。
Soil shows obvious anisotropic characteristics due to the action of deposition .However ,research on site seismic re‐sponse by considering the soil as anisotropic medium has seldom been studied .Transversely isotropic （TI） medium model is the reasonable mechanical model to describe the anisotropy of soil and is very convenient for engineering application .So ,it is of important academic significance and application value ,to carry out research on complex site response by using the TI medium model .The green′s functions for uniform distributed loads acting on an inclined line is deduced based on the exact anti‐plane dynamic stiffness matrix ,then the indirect boundary element method is proposed by using these green′s functions as fundamen‐tal solutions ,and finally ,the wave scattering problem of an alluvial valley for incident plane SH waves is studied .The method is verified and numerical calculations are performed both in the frequency and time domain by considering the medium of the al‐luvial valley and the half‐space as TI medium ,respectively .Numerical results show that the variation of the TI parameters of the alluvial mainly leads to the change of the self‐dynamic characters of the valley ,and then leads to the significance change of the peak frequency and spectral value of the surface displacement amplitude amplification spectrum on the surface of the valley ;the variation of the TI parameters of the half‐space leads to the change of the change of the impedance ratio along various direc‐tions ,and it mainly affects the amplitudes of the amplification spectrum and has little effects on the peak frequency .In addi‐tion ,the TI parameter of alluvial valley and the half‐space also has a significant effect on the wave propagation in valley and in the half‐space ,through calculating the time histories of the displacement amplitude near the valley incident by the Ricker time histories .
出处
《振动工程学报》
EI
CSCD
北大核心
2016年第4期666-678,共13页
Journal of Vibration Engineering
基金
国家自然科学基金资助项目(51578373
51578348
51578372)
作者简介
巴振宁（1980-），男，博士，副教授。电话：13752331405；E—mail：bazhenning_001@163．com
通讯作者：梁建文（1965-），男，博士，教授。E-mail：Liang@tju．edu．com
