地震波斜入射条件下重力坝动力响应分析  

Time-domain seismic response for gravity dam to obliquely incident and seismic waves

作　　者：苑举卫[1,2] 杜成斌[1] 刘志明[1] 

机构地区：[1]河海大学工程力学系,南京210098 [2]江苏鸿基科技有限公司,南京210008

出　　处：《振动与冲击》2011年第7期120-126,共7页Journal of Vibration and Shock

基　　金：973课题资助(2007CB714104);中国水利水电科学研究院开放研究资金资助项目(2008538613)

摘　　要：为建立反映设计地震动的斜入射波场,将地表地震动时程分量分解为斜入射的平面SV波和平面P波,使其共同作用下在地表产生与设计地震动分量相同的响应,而其他方向响应为0,根据固体介质中波的传播理论,推导了斜入射波入射角度之间的关系,以及幅值与设计地震动分量的联系,通过采用平面波和远场散射波混合透射的应力人工边界条件,得到了反映设计地震动的地震波斜入射条件下的解析方式,以此为基础建立了时域计算分析模型。将该方法应用于某重力坝?地基动力相互作用分析,在不同地基刚度下与垂直入射的情况进行了比较,计算结果表明:地震波斜入射时对重力坝结构有明显的影响,尤其是坝-基交界面上,结构的动力响应要大于地震波垂直入射时结构的动力响应。该方法在均匀地基假设下构造了反映地表设计地震动特征的斜入射波系,斜入射波系在地表的响应具有非一致特征,同时该方法考虑了地基的辐射阻尼,可用于重大工程在地震动非一致输入下的动力响应分析。Here,the time-domain calculating method for dynamic interaction between gravity dam and foundation object to obliquely incident and seismic waves was developed based on hypothesis of homogeneous foundation,in which both oblique plane SV wave and oblique plane P wave were input simultaneously at artificial boundary and produced similar seismic response to that of the design seismic component at surface of half space.According to theory of wave propagating in solid,both incidence angles and amplitudes of the oblique waves had deterministic relation.Taking the interaction between gravity dam and foundation as an example,its time-domain seismic response was calculated and analyzed.The preliminary results showed that obliquely incident and seismic waves have greater influence on the area near the interface of dam and foundation,where the dynamic response to obliquely incident and seismic waves is larger than that to vertically incident and seismic waves.The method took both design seismic component and radiation damping of foundation into account,and produced nonuniform motion at interface of dam and foundation,so it could be used to study dynamic response of a structure under nonuniform input.

关 键 词：时域地震响应 设计地震动 斜入射 粘弹性边界 重力坝-地基动力相互作用 

分 类 号：TV642[水利工程—水利水电工程]