PREDICTION OF NONLINEAR STRUCTURAL EARTHQUAKE RESPONSE BASED ON HYBRID METHOD CONSIDERING LOCAL SEISMIC ACTIVITIES AND UNDERGROUND SOIL CHARACTERISTICS

采用直接2.5维边界元法对三维haskell型断裂引起的二维沉积盆地强地面运动进行了评价，以估计1995年兵库根地震期间神户市重毁带地震动的放大特征。详细探讨了不同类型沉积盆地剖面对盆地强地面运动的影响。讨论了拉普拉斯方程中裂纹问题的三维快速多重边界积分方程求解方法。该方法采用Hrycak和Rokhlin提出的一种新的多极展开方法，结合配点法求解裂纹问题的离散超奇异边界积分方程。采用广义最小残差法结合快速多极子法对所得数值方程进行了求解。结果表明，当未知数大于约1300个时，所得到的编码比常规编码速度快。提出了一种计算桩顶水平荷载作用下时变非线性动力土阻力的方法。在此过程中，仅假定桩上某些点的弯矩是通过观测预先给定的。特别考虑了一种数据处理方法，该方法结合了给定数据的平滑过程和引入正则化与惩罚矩阵，以提高从观测数据（包括测量误差）估计的准确性。通过数值算例验证了该方法的有效性。

A direct 2.5 dimensional boundary element method is applied to evaluate strong ground motions in two-dimensional sedimentary basin due to a three-dimensional Haskell-type fault to estimate the amplification characteristics of the ground motions in the heavily damaged belt zone in Kobe City during the 1995 Hyogo-ken earthquake. The effects of different types of cross-section of the sedimentary basin on the strong gound motions in the basin are examined in detail.We discuss a three-dimensional fast multiple boundary integral equation method for crack problems in Laplace's equation. The proposed implementation uses a new multipole expansion proposed by Hrycak and Rokhlin in conjunction with collocation in the solution of a discretised hypersingular boundary integral equation for crack problems. The resulting numerical equation is solved with GMRES(generalised minimum residual method) in connection with FMM(fast multipole method). It is found that the obtained code is faster than a conventional one when the number of unknowns is greater than about 1300.We present a method to evaluate time-varying nonlinear dynamic soil resistance to a pile when subjected to horizontal excitations on the top of the pile. In the procedure only bending moments at some points on the pile are assumed to be given in advance by observation. Special consideration to a data processing method, which combines a smoothing procedure for given data and introduction of regularization with a penalty matrix, is made for improving the accuracy of the estimation from the observed data including measurement errors. The validity of the proposed procedure is studied and confirmed through numerical examples.