尼雅水库坝料动力特性研究及三维地震反应分析

为研究沥青混凝土心墙坝抗震能力,以新疆尼雅水库为例,利用大型三轴仪进行动模量阻尼比和永久变形试验,分析筑坝材料的动力特性,并采用等效线性黏-弹性模型和大工双曲线残余变形模型对坝体进行地震反应分析。结果表明:砂砾料和过渡料的最大动剪切模量比堆石料高4%～11%,而堆石料的最大阻尼比比砂砾料和过渡料高4%～14%;心墙沥青混凝土的最大动剪切模量随着围压和固结比的增大而增大;地震动力反应时,坝体各方向最大位移、加速度和最大永久变形均发生在坝顶处,且顺河向最大位移为0.042 m,最大加速度为4.98 m/s~2,坝体上下游土体顺河向可产生拉应力破坏,心墙最大永久变形发生在坝顶处,坝体的最大沉降比心墙高0.035 m,坝体与心墙协调变形能力较强。结果表明,尼雅沥青混凝土心墙坝"金包银"结构具有良好的抗震性能。

Dynamic characteristics of dam materials and three-dimensional seismic response analysis of Niya Reservoir

In order to study the anti-seismic capacity of asphalt concrete core wall dams, taking the Niya Reservoir in Xinjiang as an example, the dynamic characteristics of dam materials were analyzed by large-scale triaxial apparatus dynamic modulus damping ratio and permanent deformation test, and the seismic response of dam body was analyzed by using equivalent linear viscoelastic model and hyperbolic residual deformation model of Dalian Institute of Technology. The results show that the maximum dynamic shear modulus of sand gravel and transition material is 4% to 11% higher than that of rockfill material, and the maximum damping ratio of rockfill material is 4% to 14% higher than that of sand gravel and transition material. The maximum dynamic shear modulus of asphalt concrete increases with the increase of confining pressure and consolidation ratio. During the earthquake dynamic response, the maximum displacement, acceleration and maximum permanent deformation of the dam body occur at the dam crest, and the maximum displacement along the river is 0.042m with the maximum acceleration of 4.98m/s2. The upstream and downstream soils of the dam may cause tensile stress failure along the river, the maximum permanent deformation of the core wall occurs at the top of the dam, and the maximum settlement of the dam body is 0.035m higher than that of the core wall, showing strong coordinated deformation ability of the dam body and the core wall. According to the research, the gold rimming silver structure of the Niya asphalt concrete core wall dam has good seismic performance.