Dump Flooding Instability Undermine Its Engineering Disposal Applications

Dump slope immersion instability compared to ordinary landslide has two outstanding characteristics:(1) dump surface is mainly composed of stope blasting stripping waste rock composition, these loose accumulation body is the accumulation of the secondary slope, due to their dispersion, complexity and variability, but differs by not strong perturbations of the rock and soil slope composed of;(2) the slope groundwater changes influence the engineering object, not only by the influence of groundwater, the most prominent feature is the dump in tailings reservoir upstream, with the production of continuously thorough, tailings reservoir water level will rise ceaselessly, will be partially submerged dump slope, bring new security issues.This paper takes Yunnan open-pit mine tailings upstream million in Manjiazhai dump as the research object, based on the test results by means of dump granular material mechanics parameter test. Through in Manjiazhai dump950platform, the1020platform and the1130platform for in-situ shear test, obtained respectively with marble consisting mainly of dispersion, mica schist based dispersions and quartz schist based dispersion of shear strength parameters respectively:c1=101.50kPa,φ1=23.84°; c2=23.40kPa,φ2=33.89°; c3=40.70kPa,φ3=21.74°; On the gradation of dispersion were direct shear test cut test research, analysis of the cohesive force and internal friction angle with the content of coarse particles of the relationship between the change of character, and the angle of internal friction with the content of coarse particles changes in nonlinear regression equation: y=-0.00004x3+0.00286x2+0.13650x+19.91371; Cohesion with coarse grain content variation equation of nonlinear regression:y=-0.00005x3+0.00539x2+0.02875x+20.15406; Wet disintegration test change dispersion particle composition content, while the particles of the relative position changes, cause of granular materials pore ratio changes, if the reaction in the materials strength mechanism in the process of particle groups, namely the change makes the density change, the particle contact point changing, shear resistance and corresponding changes.Based on the test results, according to different height of tailings reservoir water level rise divided condition, for Manjiazhai dump stability analysis. The calculation results show that the dump with tailings water level rising, the safety coefficient decreases, until the instability. Based on the numerical results, show that tailings reservoir water level rise rear dump stability will be reduced gradually, there is possibility of landslides. In view of this situation, put forward power using gravity retaining wall and masonry slope protection way of combining reinforcement disposition, by checking the disposal measures.