矿山废石对尾矿坝浸润线的影响机理研究

Study of the Influence Mechanism of Mine Waste Rock on Saturation Line of Tailings Dam

浸润线是衡量尾矿坝稳定性的关键指标,研究浸润线埋深变化对于提高尾矿坝的稳定性有重要意义。以斋家冲尾矿坝为工程背景,利用矿山废石与尾矿砂联合堆筑的方法建立了与原型相似的含废石柱尾矿坝的试验模型,分析废石柱的颗粒级配和间距对尾矿坝不同工况下的坝体单位时间渗流量和浸润线埋深的影响,并利用Geo-studio软件中SEEP/W研究了正常工况下的坝体渗流流态。结果表明:随着废石柱细颗粒含量的降低,坝体单位时间渗流量增加,浸润线埋深则降低;随着废石柱间距的增大,尾矿坝的单位时间渗流量减小,初期坝坝前坡脚处截面流量增大,孔隙水压力线与坝基的水平夹角减小,浸润线埋深随之抬高。研究结果可为类似尾矿坝的设计与施工提供参考,有利于减少废石对生态环境的影响。

Saturation line is the key index to evaluate stability of tailings dam,and it is of great significance to study it’s depth change for improving the stability of tailings dam.Based on the engineering background of Zhaijiachong tailings dam,the test model of tailings dam with waste rock pillar similar to the prototype was established by using the method of combined heap construction of mine waste rock and tailings,and the influences of grain composition and spacing of waste rock pillars on the seepage flow per unit time and saturation line height of tailings dam under different working conditions were analyzed.The seepage flow pattern of dam body under normal conditions was studied through simulation by using the SEEP/W modules in Geo-Studio software.The results were concluded as follows.Firstly,with the decrease of the fine particle content of the waste rock pillars,the seepage flow per unit time increased and the saturation line height decreased.Secondly,with the spacing of waste rock pillars increasing,the seepage flow unit time of tailings dam decreased,the flow of cross section at the front slope foot of the dam increased in the initial stage,the horizontal angle between the pore water pressure line and the dam foundation decreased,and the saturation line height rose accordingly.The research results could provide a reference for design and construction of the similar tailings dams,and would reduce the impact of waste rock on ecological environment.