重力坝折坡点高度对其抗震性能的影响

为了研究下游折坡点高度对混凝土重力坝抗震性能的影响,应用ABAQUS软件,以1967年Koyna震害工程为原型建立二维有限元模型.结果表明:随着折坡点位置的降低,坝面突变处的拉应力值逐渐增大,其中在90%~70%阶段呈近似线性增加,70%以下增加幅度趋缓;随着折坡点高度的降低,坝体上部晃动愈加剧烈,对坝顶建筑物的安全稳定性产生严重不利影响;当折坡点的高度控制在坝高的80%以上时,可以有效减弱或避免应力集中产生的破坏.在工程设计中合理控制下游折坡点的高度对提高坝体的抗震性能起到重要作用.

Influence of height of turning point on seismic performance of gravity dam

In order to determine the influence of height of downstream turning point on the seismic performance of concrete gravity dam, the ABAQUS software was used to establish the 2D finite element model with taking the Koyna earthquake disaster in 1967 as the prototype. The results show that with reducing the position of downstream turning point, the tensile stress at the dam surface mutation gradually increases. In addition, the tensile stress approximately increases linearly from the 70% to 90% stage, and the increasing amplitude tends to slow down below 70%. With decreasing the height of downstream turning point, the dam crest shakes more and more violently, which has serious adverse effect on the security and stability of building on the dam crest. When the height of downstream turning point is controlled to be higher than 80% of dam height, the damage caused by the stress concentration can be effectively weaken or avoided. The reasonable height of downstream turning point in the engineering design has important influence in improving the seismic performance of dam. 