提出基于考虑断层模型的输入地震动评价理论,为水电工程的抗震设计和既有设施抗震复核时地震动输入(设定)提供一个有效可行的途径。该体系基于断层震源破裂模型,震源至评价场地的三维物理模型,根据差分法或波数积分法等地震理论计算与统计(经验)格林函数法的复合计算技术,进行建设场地和广域地区的地震动模拟,综合考虑了地震三个构成要素,即震源效应、传播途径和场地效应,具有明确的理论背景和可行性。符合抗震设计更为合理,同时又符合经济性的原则。该方法可提供模型区域所有地点的宽频地震动时程,对于水库下游和工程场地周围地区的抗震设防以及地震预警工作也提供了基础。
This study provides an effective method of seismic input to simulate the near-fauh ground wave motions for the anti-earthquake design or checking of hydraulic structures. This hybrid method is based on a fault rupture model, a 3D finite difference method (or discrete wave-number method), and the stochastic (or empirical) Green function for modeling the motions of 3D underground structures in the region from the earthquake source to the concerned sites. With the characterized asperity model for source heterogeneity introduced, the method has a theoretical basis and is feasible for application, conforming the seismic design principles of reasonableness and economical efficiency. Results demonstrate that source effect, propagation path and site effect (local geological conditions) are three crucial factors to the practical simulation of broad-band ground motions caused by earthquake waves. The method is useful for producing the basic data of seismic design for reservoir area and also suitable for real-time simulation.