高混凝土重力坝复杂坝基稳定安全度及极限承载能力研究

Study of stabilization safety and limit load carrying capacity for complex foundation of high concrete gravity dam

采用各向异性强化-软化的有厚度薄层单元模拟了坝基软弱夹层的力学变形特性,采用无厚度接触摩擦单元模拟坝基岩体节理裂隙,对高混凝土重力坝复杂坝基抗滑稳定采用三维非线性有限元分析,利用强度储备系数法模拟坝体坝基系统的渐进破坏过程、可能失稳模式,提出了塑性屈服区贯通的强度分析方法、典型特征点位移突变的变形体分析方法以及能量法联合判定坝体坝基系统极限承载力的研究方案,得出了坝体坝基系统的极限承载力。最后针对建设中的向家坝水电站高重力坝的深层抗滑问题进行了三维非线性有限元分析,计算结果表明,系统的极限承载能力由夹泥层的强度控制,极限状态的强度储备系数为2.7。

A kind of layer element with thickness and anisotropic hardening-softening character is adopted to simulate mechanics and deformation characteristic of soft interlayer in dam foundation.Contact friction element with no thickness is applied to simulating the joint in rock.Three-dimensional nonlinear finite element analysis is performed for slide resistance in deep foundation.Intensity safety factor is adopted to simulate gradual destroy progress and potential destabilization pattern.A judge method for limit load carrying capacity is presented,which synthesizes plastic zone pierce method,displacement jump of typical position and energy method.Then limit load carrying capacity of dam system is gained and slide resistance is evaluated.The finite element calculation results of actual project show that the limit load carrying capacity of dam system is decided by intensity of soft interlayer.Limit intensity safety factor is 2.7.