上游式尾矿坝地震响应实例分析

摘要

The various tailing ponds in the vicinity of Tangshan were damaged seriously affected by the Tangshan earth-quake (Ms=7. 8,28-July-1976). In order to study the seismic response characteristics of the tailings dam,influences of Tangs-han earthquake on tailings particle size distribution,shear strength and compressibility were analyzed based on geological explo-rations before and after the earthquake. The results presented that:① After the Tangshan earthquake,the content of fine grain increases in superstratum of the tailings dam(buried depth≤12 m),decreases in lower stratum(12~ 25 m depth range).②The influence of earthquake on the tailings dam characterize as region. The internal friction angle becomes smaller,the tailings get looser in superstratum and more dense in lower stratum in the area close to the downstream dam slope,while the tailings are getting looser in lower stratum and more dense in superstratum in the area near waterline in reservoir.③Compression properties of tailings are almost not influenced in the Tangshan earthquake action. The research achievements can provide reference for seismic design of upstream tailings dam in earthquake area.%1976年7月28日发生的唐山大地震对区域内的多个尾矿坝造成了不同程度的破坏.为研究地震作用下尾矿坝体的响应特征,以唐山地震前后某尾矿坝勘察成果为依据,分析了地震对尾矿粒度分布、抗剪强度及尾矿压缩特性的影响.研究结果表明:①地震后,尾矿坝上层(埋深≤12 m范围)细粒尾矿增加,下层(埋深12~25 m范围)细粒尾矿减少.②地震对尾矿坝的影响具有区域性.地震后靠近下游坝坡区域尾砂内摩擦角总体降低,上层尾矿变松散,下层尾矿变密实;靠近库内水边线区域,上层尾矿变密实,下层尾矿变松散.③地震作用下尾矿的压缩特性基本不受影响.研究成果可以为地震区上游式尾矿坝的抗震设计提供参考.