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 can’t meet the demand of dumping,so it needs to dump in the anticline area.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 anticline area are 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 Morgenstern-price method is used to study the slip mode and stability changes of the dumping bench when the single-step tracking dump in the anticline area is 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 coefficient index and dumping volume index are constructed,the entropy-based TOPSIS method is used to weight the selected indicators,and the best plan for substrate processing is 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 surface 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.