基于Davidenkov本构模型的三维沉积盆地非线性地震动谱元法模拟  

Nonlinear ground motion simulation of three-dimensional sedimentary basin based on Davidenkov constitutive model and spectral element method

作　　者：巴振宁[1,2,3] 赵靖轩 桑巧稚 梁建文[1,2,3] BA Zhenning;ZHAO Jingxuan;SANG Qiaozhi;LIANG Jianwen(Key Laboratory of Coast Civil Structure Safety of Ministry of Education(Tianjin University),Tianjin 300350,China;Laboratory of Earthquake Engineering Simulation and Seismic Resilience of China Earthquake Administration(Tianjin University),Tianjin 300350,China;Department of Civil Engineering,Tianjin University,Tianjin 300350,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]滨海土木工程结构与安全教育部重点实验室,天津300350 [2]天津大学中国地震局地震工程综合模拟与城乡抗震韧性重点实验室,天津300350 [3]天津大学土木工程系,天津300350 [4]同济大学地下建筑与工程系,上海200092

出　　处：《岩土工程学报》2024年第7期1387-1397,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52178495);国家自然科学基金地震科学联合基金(重点)项目(U2139208)。

摘　　要：为研究三维沉积盆地内低波速土体非线性反应对近断层地震动的影响,实现基于物理的全过程(震源破裂-地震波传播-复杂场地效应-近地表土体非线性反应)三维复杂场地地震动模拟,在谱元SPECFEM3D程序中进行二次开发,采用目前具有丰富工程应用且适用于不同土类的三参数Martin-Seed-Davidenkov本构模型,结合已有的不规则加卸载准则,通过在程序中修改每个显式时间步下的应力增量,实现了土体剪切模量的实时更新和加卸载拐点的有效识别,将土体的非线性特性纳入到三维复杂场地地震动模拟中。首先将建立的三维模型通过施加合理边界退化至一维,与一维非线性动力分析软件DEEPSOIL的结果进行了对比,验证了开发的正确性;进而将开发的程序应用于中国滇西南地区施甸盆地的非线性地震动模拟,并与相应的线性结果进行了对比。结果显示,受土体非线性的影响,施甸地区PGA和PGV较线性结果峰值均降低,且非线性土体对PGV的影响更加明显,较线性结果最大降低约30%;沉积非线性使沉积内部观测点的速度及其反应谱幅值降低,且特征频率向长周期方向移动。In order to study the influences of nonlinear response of low-wave velocity soil on near-fault ground motion in three-dimensional sedimentary basin,and realize the simulation of three-dimensional complex site ground motion based on the whole process of physics(source rupture-seismic wave propagation-complex site effect-near-surface soil nonlinear response),the secondary development is carried out in the spectral element method code-SPECFEM3D.The three-parameter Martin-Seed-Davidenkov constitutive model with generous engineering applications and suitable for different soil types is adopted.Based on the existing irregular loading and unloading criteria,the real-time updating of shear modulus of soil and the effective identification of loading and unloading inflection points are realized by modifying the stress increment at each explicit time step in the code.The nonlinear characteristics of soil are incorporated into the three-dimensional complex site ground motion simulation.The established three-dimensional model is first degenerated to one-dimensional one by applying a reasonable boundary,and compared with the results of one-dimensional nonlinear dynamic analysis software DEEPSOIL to verify the correctness of the development.Furthermore,the developed code is applied to the nonlinear ground motion simulation of the Shidian Basin in southwestern Yunnan province,China,and compared with the corresponding linear results.The results show that the peak values of acceleration and velocity in Shidian area are lower than those of linear results,and the influences of nonlinear soil on PGV are more obvious,which is about 30%lower than that of linear results.The deposition nonlinearity reduces the velocity and amplitude of response spectra of the receivers inside the deposition,and the characteristic frequency moves to the long period direction.

关 键 词：非线性地震反应 三维沉积盆地 Davidenkov本构模型 谱元法 

分 类 号：TU435[建筑科学—岩土工程]