基于Geo-studio的尾矿库加高扩容后坝体稳定性分析

Stability analysis of tailings dam after heightening and capacity expansion based on Geo-studio

加高已有尾矿坝是扩大尾矿库库容的一种经济可行的办法,但尾矿库等级升高,溃坝风险增大。以辽宁某尾矿库为例,通过现场勘查和室内试验获得堆积层基本物理力学参数;对比实测浸润线,利用Geo-studio软件模拟分析尾矿坝加高前后渗流场并优化渗透系数,进一步分析坝体静力稳定性和地震动力响应。结果表明:尾矿库浸润线最小埋深在10 m以上,符合规程要求;采用瑞典圆弧法和简化Bishop法计算的安全系数均高于允许最小安全系数,地震对坝体安全性影响较小,只有局部液化;加高后最危险滑面位于初期坝附近370 m标高以下,主要为深层圆弧形滑移,原因是尾粉土渗透性较低导致浸润线升高,建议实时监测尤其是洪水期浸润线高度,必要时采取相应措施降低浸润线,有效杜绝渗透破坏。

It is an economic and feasible method to enlarge the capacity of the tailings pond by heightening the existing tailings dam.However, the grade of the tailings pond increases, and the risk of dam break increases.Taking a tailings pond in Liaoning province as an example, the basic physical and mechanical parameters of the accumulation layer are obtained through field investigation and laboratory tests.Compared with the measured phreatic line, the seepage field of the tailings dam after heightening is simulated and analyzed by Geo-studio software, the permeability coefficient is optimized, and the static stability and seismic dynamic response of the dam are further analyzed.The results show that the minimum buried depth of the saturation line of the tailings pond is more than 10 m, which meets the requirements of regulations.The safety factors calculated by the Swedish slip circular method and simplified Bishop method are higher than the allowable minimum safety factor.The earthquake has little impact on the safety of the dam, and only local liquefaction is found.The most dangerous sliding surface of the heightened tailings dam is located near the initial dam and below the elevation of 370 m.The reason is that the permeability of tail silt is low, increasing by increasing phreatic line.It is recommended to monitor the height of the phreatic line in real-time, especially during the flood period.If necessary, take corresponding measures to reduce the phreatic line, to effectively prevent seepage damage.