Research On Stability And Parameter Optimization On The Roof Side Of Cross Exploitation And Inner Dumping In Zhahanaoer Open-pit Mine

Zhahanao’er open-pit mine achieves cross exploitation and inner dumping.Implementate the cross arrangement of the working line,along strike to advance,and dump waste disposal into internal waste dump mining procedures,top slop of cross exploitation and inner dumping is the north slope of the original vertical mining.It is inverse-dip layered slope of compounded coal seam and slope body occurs weak layer which are consistent with coal seam.It is important preconditions to study on the stability of slope under these conditions and design parameters of edge slope for safely,economically and reasonably mine overlaid minerals.According to cross exploitation and inner dumping top slope in the Zhahanao’er Open-pit Mine supported by dumping covering being time effect and space effec,the paper research on the stability variation and failure mode of composite slope based on field investigation,theoretical analysis,two-dimensional limit equilibrium,and three-dimensional numerical simulation.Base on cross exploitation and inner dumping have time-space effect on the top side slope,from two-dimensional point of view,adopting method of level by level optimization is to redesign slope final highwall parameters.Through three dimensional slope stability and failure mechanism of spatial deformation under simulated internal pressure,verify the rationality of the optimized slope.Research shows that weak layer reduce slope stability.Because cross exploitation and inner dumping top slope in the Zhahanao’er Open-pit Mine produce time effect and space effect,lead stability factor of differrent horizons require 1.2,1.1,1.05 from top to bottom.The angle of slope entirety increase to 29° after level by level optimization,and mining angle of deep and steep slope is increase to 34°.The optimized slope meets the stability requirements.It is primary cause of stress concentration at the toe of slope that weak layer give rise to inelastic yielding under the self weight stress.The paper provides guidance for north slope treatment in the Zhahanao’er Open-pit Mine and provide reference for slope stability analysis under similar conditions.