【摘要】 在显式有限元方法结合黏弹性人工边界的时域波动方法的基础上,建立了地震波垂直输入时的一种简化输入方法。将近场有限元模型沿高度方向进行分层,将地震动的入射运动转化为作用于人工边界底面及分层后每层侧面上的均布力,以实现地震动的输入。与以等效节点力的方式实现的地震动输入相比,施加均布力的方式简化了地震波输入的前处理工作,且又能保证与等效节点力方式相同的精度。自由场数值算例表明:当该方法中的分层高度与波动有限元网格离散要求的最大尺寸相等时,该方法与等效节点力方法具有相同的精度;当局部区域按网格离散要求的最大尺寸进行分层而在其它区域放大分层高度时,局部区域上的近场波动响应仍可保证具有相当高的精度。另外,某隧道结构地震响应算例的计算结果同样说明了该方法的有效性。更多还原

【Abstract】 On the basis of the time-domain wave method combined with the explicit finite element method and the viscous-elastic artificial boundary condition,a simplified seismic wave input method for near-field wave analysis was proposed. With this approach,the near-field model was stratified in the height direction,and then the seismic motion was converted into stresses acted on the viscous-elastic artificial boundary to realize seismic wave input. Compared with the equivalent node force input method,the new method simplified the antecedent processing with an acceptable accuracy.The numerical results obtained from a free ground model indicated that when the stratified size equals the maximum size of the element mesh in dynamical analysis,the accuracy of the simplified method is the same as that of the equivalent node method; when the local parts of the near-field model were stratified with the maximum element mesn size of dynamical analysis while the other parts were stratified with a lager size,the dynamic responses of the local parts have a higher accuracy. Moreover,the dynamic response computation results of a rock tunnel demonstrated the effectiveness of the proposed simplified approach.更多还原