露天矿背斜区内排土场边坡基底处理方式优选研究

露天矿内排土场边坡的稳定是露天矿顺利生产的重要保障,而排土场基底的岩层赋存条件是影响排土场边坡稳定性的重要因素。安家岭露天矿开采进入背斜影响区,现有内排空间无法满足排土需求,需要在背斜区进行排土。为解决露天矿背斜倾角较大区域倾斜基底排土场稳定性问题,以安家岭露天矿内排土场为研究对象,提出了针对背斜区倾斜基底进行处理的3个方案:基底麻面爆破处理,跟踪排弃台阶坡脚处拉抗滑沟处理以及背斜区倾角12°位置留设抗滑煤柱;使用Geo-studio软件Morgenstern-Price法研究在不同基底处理方式下进行背斜区单台阶跟踪排土,排土台阶的滑移模式以及稳定性变化情况。通过计算各个方案的经济成本,跟踪排土台阶稳定性系数以及背斜区域的单位排土量,构建了成本、稳定性系数、排土量3个评价指标,采用基于熵权TOPSIS法对所选指标进行加权,并根据方案与理想解的贴近度大小确定基底处理的最佳方案。研究结果表明:背斜区单排土台阶滑移模式为以排弃台阶坡顶至排弃物料内部的圆弧滑面为侧滑面,以沿着基底平面为底部滑面的切层-顺层滑动;相同排弃参数的排弃台阶,在基底坡度从陡变缓的过渡区域,排土台阶的基底平面接近于圆弧面,且单台阶排弃量增加,台阶稳定性发生突变,安全系数较上部台阶显著降低;通过基于熵权TOPSIS法对3个方案进行优选,确定麻面爆破方案为基底处理的最优方案。

Study on optimization of treatment methods for inclined basement of inner dump slope in anticline area of open-pit mine

The stability of the side slope of the dump in the open-pit mine is an important guarantee for the smooth production of open-pit mine,and the rock formation conditions at the base of the dump is an important factor affecting the stability of the dump.As Anjialing Open-pit Mine access into the anticline area,the existing internal drainage space couldn′t meet the demand of dumping,so it needs to dump in the anticline area.In order to solve the stability problem of dump overlying the bedrock with large dip angle in Open-pit Mine,taking the internal dumping of the Anjialing Open-pit Mine as the research object,three methods for dealing with the inclined basement in the anti?cline area were proposed:the blasting treatment on the pockmarked surface of the basement,anti-sliding ditch excavation treatment at the foot of the track dumping step slope,anti-sliding coal pillars at the 12°dip in the anticline area.The Geo-studio software Morgensternprice method was used to study the slip mode and stability changes of the dumping bench when the single-step tracking dump in the anti?cline area was performed under different substrate treatment methods.By calculating the economic cost of each plan,tracking the stability coefficient of the dumping bench and the unit dumping volume in the anticline area,three evaluation indicators of cost index,stability coef?ficient index and dumping volume index were constructed,the entropy-based TOPSIS method was used to weight the selected indicators,and the best plan for substrate processing was determined according to the degree of closeness between the plan and the ideal solution.The results of the study show that:the slip pattern of the single-dumped soil steps in the anticline area is that the arc sliding surface from the top of the dumping step slope to the inside of the dumping material is the side sliding surface,and the base plane is the bottom sliding sur?face these two sliding surfaces causes the cut-to-layer sliding;for the dumping steps with the same dumping parameters,in the transition area where the base slope changes from steep to gentle,the base plane of the dumping steps is close to the arc surface,and the single-step dumping volume increased,the stability of the steps changes suddenly and the safety factor is significantly lower than that of the upper steps;the three schemes are optimized through the entropy-based TOPSIS method,and the pockmarked blasting scheme is determined as the optimal scheme for substrate treatment.