某尾矿坝稳定性分析与加固措施

Stability Analysis of a Tailing Dams and its Strengthening Measures

针对某尾矿库堆积坝下游坡出现的水流高位出逸及流砂现象,对该尾矿坝进行了渗流与稳定计算,提出了渗流和稳定评价意见及可行的除险加固方案。研究内容包括:采用先进的三维激光扫描仪对尾矿坝及其附近区域进行大比例尺地形测量,现场测量堆积坝坡及干滩坡比,为数值计算提供基础地形资料;现场取尾矿砂样本,进行室内试验,包括颗粒分析、渗透性和强度参数试验等;根据下游坡出逸点高度进行渗流计算输入参数反分析,获取合理的尾矿砂渗透系数各向异性比例与坝顶垂直入渗流量;对尾矿坝现状与远期规划坝高进行6个工况的渗流与抗滑稳定分析,指出坝体处于滑动失稳临界状态,提出采用辐射井降水的排渗措施。该尾矿库采用辐射井降水后,稳定安全系数提高至1.7以上,坝体下游坡水流高位出逸和流砂管涌现象已基本消除。

The phenomena of flowing sands and water exit at high positions on the downstream slope of a railings filled dam were focused in the seepage and stability analysis of the tailing dams to propose a safety evaluation of its seepage and stability, and strengthening measures in this paper. The safety evaluation included： a field surveying of the topography of the tailing dams and its neighboring area with an advanced 3D laser scanner to provide basic data for numerical computation; an indoor laboratory testing of samples from the tailing dams consists of grain distribution, permeability, and shear strength tests; a back-analysis based on the heights of water exit position to get proper anisotropic values of hydraulic seepage in railings and vertical flux on the top of the dam; a series of seepage and stability analyses for six cases of dam heights accounting the current state and the future plans of the tailing dams indicate that the dam was under a critical state of sliding failure, and the radiation wells should be implemented as precipitation measures to strengthen the tailing dams. After adoption of the strengthening measures, the safety factor has been increased over 1.7 so that the phenomena of water exit at high positions and piping on the downstream of the dam have been eliminated.