观音岩水电站混合坝接头结构形式研究

Study on configuration shape of concrete connection of Guanyinyan Mixed Dam

将无厚度接触摩擦单元,引入观音岩混合坝接头的堆石体与混凝土挡墙之间的接触面力学行为进行模拟。采用Ducan双曲线E-B模型模拟堆石体及心墙的本构关系,考虑堆石坝的实际填筑施工过程和水库蓄水过程,对接头处的结构形式进行了接触面坡度变化和水平面上转角变化的敏感性分析,以揭示竣工期和运行期不同接头结构形式接触面上的法向应力、接触状态和可能发生水力劈裂的范围,推荐最优的接头结构方案。大坝连接坝段的三维非线性仿真分析结果表明,心墙接触面上的法向正应力均为压应力,接触面坡度越陡,接触面法向压应力越小;混凝土挡墙向上游转动的转角越大,法向压应力越大。综合来看,插入式方案4的接头部位的综合防渗性能最好,因此推荐该方案为混合坝接头的结构设计方案。

The non-thickness contact friction element is presented to simulate the mechanical behavior of contact surface between rockfill and concrete retaining wall for Guanyinyan Hydropower Station mixed dam, which makes up of a rockf/ll dam and a miler compacted concrete gravity dam. The Ducan hyperbola E-B constitutive model is applied to simulate rockfill body and clay core wall＇s stress-strain relations. Considering actual construction process and impounding process, sensitivity analysis are performed for varying of configuration shape of concrete connection, which include contact surface slope changing and contact surface rotating to upstream on horizontal plane. Normal stress, contact state and latent water power crack area of contact surface for different configuration shapes of concrete connection can be revealed through sensitivity analysis. So the better configuration shape of concrete connection can be recommended. The three-dimensional nonlinear FEM simulation results show that normal stress on contact surface of clay core wall is all compression stress; the one is smaller when contact surface slope steeper and rotation angle smaller to upstream. In sum the seepage prevention of the fourth design scheme among wrapped connection configuration shape is better than others from a comprehensive consideration, which will be recommended to be the design scheme.