【摘要】 目的针对水平地震力作用下钢板桩围堰体系的动力受力变形特性分别进行振型分解反应谱分析和动力时程分析,并将计算结果加以比较,为工程设计与实践提供参考依据.方法通过建立双排钢板桩围堰体系动力有限元数值模型,采用Lanczos特征值法提取围堰体系自然频率与振型,利用Newmark逐步积分方法求解考虑几何非线性的动力平衡方程.结果双排钢板桩围堰体系振动固有周期较小,围堰体系正向平动刚度较负向平动刚度要小;在水平地震力作用下,围堰体系地震水平位移响应在围堰上部靠近外侧区域最为显著;外侧钢板桩受力变形响应较内侧钢板桩更为显著.结论内、外侧钢板桩水平位移分布均随着高度的增大而增大.相反的,内、外侧钢板桩广义剪应力分布均随着高度的增大而减小.更多还原

【Abstract】 Based on the computational FEM model of cofferdam system with steel sheet piles,numerical analyses with both response spectrum and step-by-step integration methods are conducted by using Lanczos eigenvalue extraction technique to obtain natural frequencies and modes.Dynamic equations are solved with Newmark implicit method considering geometric nonlinearity.Furthermore,results comparison between different methods are made and the conclusion may provide some reference for engineering practice and design.The computational results show that the natural frequency of cofferdam system is low and the horizontal translation stiffness of cofferdam in positive direction is higher than that in negative direction.Under seismic excitation,the displacement response of inner steel sheet is much more obvious than that of outer one.And the distribution of horizontal displacements in steel sheets presents the characteristics that the corresponding values increase with their heights in the cofferdam system.On the contrary,the deviatonic stresses of cofferdam decrease with the augments of height.更多还原