地震波斜入射下水下地基场地的等效线性化分析方法及应用  

Application of equivalent linear method in underwater site analysis under oblique incidence of seismic waves

作　　者：张奎[1] 李伟华[1] 赵成刚[1] ZHANG Kui;LI Weihua;ZHAO Chenggang(School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《振动与冲击》2020年第22期41-49,共9页Journal of Vibration and Shock

基　　金：国家重点基础研究发展计划(“973”计划)项目(2015CB0578000);国家自然科学基金项目(51378058);中央高校基本科研业务费专项(2015JBZ008)。

摘　　要：水下地基场地动力响应分析是水下结构抗震设计的基础,但其作为一个多介质耦合的复杂动力问题,现有的研究成果多是将饱和土体视为线弹性材料,考虑土体非线性的研究相对较少。在水-成层饱和土-基岩场地地震波线性解的基础上,建立了平面波斜入射下水下地基场地分析的二维等效线性化方法,通过典型场地分析,研究了入射波峰值加速度、水深及上覆软土层厚度对水土交界面处峰值加速度放大系数的影响规律。研究结果表明:非线性效应对水平峰值加速度放大系数的影响要比竖向的大,且非线性下的放大系数可能大于线性情况下的地震响应结果;水层分别在P波和SV波入射角15°~70°和45°~70°内对水平峰值加速度放大系数产生了较大的影响。P波作用产生的影响随着水深的增加而减小,SV波的影响则与入射波有关。相比于SV波对竖向峰值加速度放大系数的影响,P波的影响作用更大;上覆软土层较厚时对水平峰值加速度放大系数的影响较为明显,并且SV波的作用时软土层的影响明显大于P波作用时,但两者对竖向峰值加速度放大系数的影响均较小。The dynamic response analysis of the underwater site is the basis of aseismic design of underwater structures.However,since the dynamic problem of underwater site is a multi-media coupling and complex problem,the existing research results mostly regard saturated soil as an elastic single-phase material.There are few studies on the nonlinearity of saturated soil.Based on the linear solution of the water-stratified saturated soil-bedrock site,a two-dimensional equivalent linearization method under oblique incidence of seismic waves was established.A typical site analysis was explored to study the effects of the peak acceleration of incident wave,water depth and overlying soft soil thickness on the peak acceleration amplification coefficient at the interface of water and soil.The results show that compared with the vertical peak acceleration amplification factor,the nonlinearity has a greater effect on the horizontal result,and the nonlinear amplification factor may be greater than the linear result.The water layer has a greater effect on the horizontal peak acceleration amplification coefficient in the range of 15°-70°and 45°-70°incident angles of P wave and SV wave respectively,and P wave has a more obvious effect on the vertical peak acceleration amplification coefficient than SV wave.When the overlying soft soil layer is thick,it has a greater effect on the horizontal peak acceleration amplification coefficient in the range of 35°-70°P wave incidence angle,and SV wave has a greater effect on the horizontal peak acceleration amplification coefficient than P wave,however,either of P wave and SV wave has little effect on the vertical peak acceleration amplification coefficient.

关 键 词：水下地基场地 等效线性化法 平面波 峰值加速度 

分 类 号：TU43[建筑科学—岩土工程]