混凝土防渗墙变形与应力分布特性

Deformation and stress distribution characteristics of concrete cut-off wall

以建于覆盖层上的土石坝为背景,对80m深覆盖层上的沥青混凝土心墙坝进行填筑和蓄水三维有限元数值精细模拟,采用非协调元模拟防渗墙单元以更精确地描述其弯曲变形模式.分析不同加载时段防渗墙的变形规律,并讨论墙体应力分布规律及其拉应力产生演化机理.结果表明:满蓄期,防渗墙岸坡附近的弯曲变形较大,是较危险部位,墙体下游侧的岸坡附近处于受拉状态.弯曲引起的墙体下游侧拉应力与下游墙面的夹角基本小于30°,且在下游墙面的投影偏向坝轴向.改善下游侧覆盖层土体特性能有效降低该区域的拉应力.研究成果可为深厚覆盖层中防渗墙的合理设计提供参考.

Three-dimensional finite element analysis were carried out on the background of dams built on overburden,to simulate the layered filling and water impounding process of an asphalt concrete core dam built on an 80 m deep overburden.Nonconforming element was employed to present more precisely the deformation modes of the concrete cut-off wall built in the overburden.The deformation behavior of the cut-off wall was analyzed at different stages.The stress distribution rule and mechanism in cut-off wall were presented.As results,the part near the bank slop of the cut-off wall has large bending at full storage stage,which is relatively dangerous.The downstream side of concrete cut-off wall is in a state of tension.The angle between the tensile stress caused by bending and the downstream surface was less than 30°;the projection for the tensile stress on downstream surface tends to the dam axial direction.The tensile stress can be effectively reduced if the soil on downstream side of the wall is reinforced.The research results can offer reference for reasonably designing a concrete cut-off wall built in overburden.