Stability Analysis Of A Dump Based On Nonlinear Strength Index

The dumping site,as an engineering facility for storing waste stripped materials in open-pit mines,is a unique high,large and loose material accumulation formed by manpower.The construction of large-scale ultra-high dumping sites is a major measure to reduce land mining in my country's mining projects.With the increase of the dumping height,the internal stress of the dumping yard becomes larger and larger,which causes the particle crushing effect of the dumped materials.The traditional linear strength index cannot accurately reflect the stability of the dumping yard slope.This paper takes the stability of a large-scale ultra-high dump in an iron mine as the main research objective,and uses nonlinear strength indicators to analyze the stability of the dump.(1)Through on-site reconnaissance and investigation,according to the existing historical data of the dump site,the hydrometeorological and topographic features of the site of the dump site are explained.Perform on-site moisture content test,particle size screening test,on-site large single volume test,etc.to determine the moisture content,density and particle size composition of the dumped materials;at the same time,take a certain amount of dumped materials for triaxial shearing Shear test to determine the stress-strain relationship and nonlinear strength index of the dumping site materials,which provides the basis for the dumping site seepage analysis and dump site stability analysis.The results show that the shear strength index of the bulk material of the dump site has different degrees of reduction under the action of a certain confining pressure.(2)Regarding the bearing capacity of the dump site foundation,two calculation methods were selected to analyze the maximum pile height that the dump site foundation can bear.The analysis results show that the dump site foundation bearing capacity meets the design stacking requirements.(3)According to the actual project,the 1-1 section,the 2-2 section and the 3-3 section with protection objects in the downstream were selected to establish a numerical simulation analysis model for the seepage flow of the dump,and the characteristics of the seepage field of the dump slope were studied..The results show that under different rainfall conditions,the impact depth of the transient saturated zone is different,and the volumetric water content of the characteristic points of the slope surface shows an increasing trend;under the conditions of equal intensity rainfall,the rainfall duration is the main factor that causes the slope seepage field change.(4)Based on the analysis of the seepage field of the dump slope,the nonlinear strength index is used to calculate and analyze the stability of the dump,and a calculation model that can reflect the actual boundary conditions of the dump is established,taking full account of the high confining pressure.The impact of particle fragmentation on slope stability.Study the overall safety factor of the dump site and the slope stress distribution law to comprehensively analyze the slope stability under normal operating conditions and seismic conditions.Comparing and analyzing the stability of the dump slope under the linear strength index,it can be seen from the analysis result that the safety factor calculated by the linear strength index is smaller than the safety factor calculated by the nonlinear calculation,and the linear index is used to calculate the coarse-grained material slope.It may be conservative;rainfall will reduce the safety factor of slopes,and the greater the rainfall intensity,the more obvious the degree of safety factor reduction.In this paper,based on the limit equilibrium method,nonlinear strength indexes are used to analyze the stability of the high slope of the dump.