多座已建高面板堆石坝在运行期或遭遇地震时面板发生了挤压破坏现象。本文采用三维静、动力有限元方法,分析了高面板堆石坝面板的坝轴向应力分布规律,研究了竖缝压缩模量对面板挤压应力的影响。分析表明:满蓄时由于水压力的作用,堆石体对面板产生指向河谷的摩擦力,因此面板的坝轴向应力以压应力为主,最大值发生在河谷中部,面板两岸坝肩局部存在较小的拉应力;地震后大坝发生整体沉陷,导致河谷中央坝顶区域面板的坝轴向压应力最大。随着坝高的增加,运行期和地震期面板的坝轴向压应力均逐渐增大。将河谷中央面板主要受压区的竖缝采用压缩模量较低的填充材料后,能有效减轻面板的坝轴向压应力。
Extruding rupture of face slabs occurred on some of the built high concrete-faced rock-fill dams(CFRD).In this paper,a three-dimensional(3-D) static and dynamic finite element(FE) method is used to analyze the axial stresses of CFRD face slabs,and the influence of compressive modulus of vertical construction joints on axial compressive stress is studied.The analysis shows that water pressure-caused friction force of face slabs points to the valley and it produces compressive stresses in most parts of face slabs.Hence the compressive stress that has a peak value at the center of valley area,dominates the dam-axial stress,and small tensile stress occurs only locally around the dam abutments.If earthquakes occur,an overall subsidence of the dam causes a significant increase in the peak compressive stress,and shifts its location to the dam crest around the central valley.The compressive stress of face slabs gradually increases as the dam height increases.Thus an effective method of reducing the axial compressive stress is the use of filling material of lower compression modulus for the vertical construction joints in the central valley region.