震源破裂产生速度大脉冲对沉积盆地长周期非线性效应的影响研究

It is the current international issue that studying on nonlinear long-period effect of sedimentary basins during the large velocity pulse with complex source rupture process. The conventional methods are difficult to apply because of hysteretic nonlinear seismic response of the earth surface shallow structure in time domain, long-period resonance of the interaction on predominant period of large velocity pulse ground motion and the natural period of sedimentary basin structure. In this project, rich explore results in recent years of Yuxi area in Yunnan Province, which are shallow seismic reflection exploration, microtremor observations, seismic borehole exploration, magnetotelluric method, gravity measurements, electrical resistivity probe are used, simultaneously, the information imaging technology and the additional work on site are increased, integrated geophysical methods of sedimentary basin structure probe are proposed, and “Wisdom” China fine Yuxi-Jiangchuan-Tonghai three-dimensional basin structure models are built. The second, Newmark "new" explicit numerical integration formula in decoupled near-field wave propagation numerical simulation technology(DWPT), and combination of the discrete grid four-time accuracy of GMS finite difference method are put forward, and Qujiang seismogenic fault are implemented by several source rupture mode and multiple complex rupture process, researching the relations of large velocity pulse, the source rupture mode and process, generation mechanism of large near-fault velocity pulses are studied. Then, the nonlinear long-period ground motion effects of Yuxi-Jiangchuan-Tonghai sedimentary basin are simulated and analyzed. There are important theoretical and engineering values for revealing long-period seismic characteristics of sedimentary basins, estimating nonlinear seismic response of complex site and strong ground motion input of major projects, and revising seismic design of long-period engineering structures.

复杂震源破裂产生速度大脉冲对沉积盆地长周期非线性效应的影响研究是当今国际前沿课题，因速度大脉冲强震动与沉积盆地长周期共振产生强烈非线性，使得常规方法难以适用。拟利用近年来在云南玉溪地区开展的浅层地震反射勘探、地脉动观测、地震钻孔探测、大地电磁测深、重力测量、电阻率探测等探测结果，采用信息技术完善与野外探测补充，提出一套沉积盆地综合地球物理探测方法，构建“智慧”中国玉溪-江川-通海沉积盆地三维结构模型。建立Newmark“新”显式数值积分格式DWPT解耦近场波动数值模拟技术与不连续网格4阶精度GMS有限差分有机结合方法，在曲江发震断层上研究多种震源破裂模式和复杂震源破裂过程与速度大脉冲之间的关系，探讨近断层速度大脉冲的产生机理，数值模拟玉溪-江川-通海沉积盆地的长周期非线性地震动效应。该研究对于刻画盆地效应、估计场地非线性地震响应和长周期工程结构的抗震设计等均具有重要的理论意义和工程价值。

复杂震源破裂产生速度大脉冲对沉积盆地长周期非线性效应的影响研究是当今国际前沿课题，因速度大脉冲强震动与沉积盆地长周期共振产生强烈非线性，使得常规方法难以适用。利用近年来在云南玉溪地区开展的浅层地震反射勘探、地脉动观测、地震钻孔探测、大地电磁测深、重力测量、电阻率探测等探测结果，采用信息技术完善与野外探测补充，提出了一套沉积盆地综合地球物理探测方法，构建“智慧”中国玉溪-江川-通海沉积盆地三维结构模型。建立Newmark“新”显式数值积分格式DWPT解耦近场波动数值模拟技术与不连续网格4阶精度GMS有限差分有机结合方法，在曲江发震断层上研究多种震源破裂模式和复杂震源破裂过程与速度大脉冲之间的关系，探讨近断层速度大脉冲的产生机理，数值模拟了玉溪-江川-通海沉积盆地的长周期非线性地震动效应。该研究对于刻画盆地效应、估计场地非线性地震响应和长周期工程结构的抗震设计等均具有重要的理论意义和工程价值。