强震区堆石坝应力变形的DDA法分析

基于非连续变形分析方法(DDA),针对堆石坝中堆积颗粒的应变特性,对各部分程序建立或改进了接口,实现了堆石料的随机分布,并且能够满足级配要求;同时也实现了堆积颗粒在筑坝中逐层堆积、逐层加载的过程。探索了DDA中弹簧刚度和步位移比的最佳取值范围。在此基础上,分析了堆石坝施工、蓄水及地震作用下的应力变形特征。结果表明:施工过程中坝体的沉降量最大;蓄水后,坝体两侧水平位移变化明显,出现向下游偏移的趋势;在地震波作用下,坝体水平向和竖向加速度峰值随高程增加而增大,符合一般堆石坝规律,表明改进后的DDA程序具有较好适用性。

Discontinuous deformation analysis of stress and deformation of rock-fill dam in meizoseismal area

Based on the discontinuous deformation analysis ( DDA) and in view of the strain characteristics of the accumulated particle in rock fill dams, by modifying some part of the original DDA and developing some interfaces, we achieve the random distribution of rockfill material that could meet requirements of gradation, also realize the layer-by-layer accumulation and loading of different particles in dam filling process. The optimal range of two important parameters in DDA of the spring stiffness and the displacement ratio are explored. On this basis, we use the DDA to analyze the stress and deformation characteristics of a rock-fill dam in construction, water impoundment and earthquake condition. The results show that the dam settlement in con-struction period is the largest;after water impoundment, the horizontal displacement at two-side of the dam changes obviously, showing a tendency to the downstream;under seismic condition, the horizontal and vertical peak acceleration increase with dam elevation, which is in accordance with general principles, proving the applicability of the DDA program.