Stability Evaluation Of Open-pit Mine Slope Based On Fuzzy-random Reliability

Abstract:Due to the varied topography and natural factors in China, slope management has become an important content of the open-pit mine safety management. Any details negligence may result in landslide hazard, it is not only a security risk for open-pit mining, but also a huge threat to the personal safety of staff and corporate property.By taking Luo-Mu East Gobi open-pit mine as the research object, risk identification, reliability analysis and integral stability evaluation of the slope were studied. Meanwhile, the influencing factors and rating of slope stability were investigated. Works that have been done in this paper includes the following:1. The dangerous source of the factors affecting slope stability was identified after stope field survey and rock sampling.Firstly, based on ANSYS and FLAC3D software modeling, the open-pit slope engineering model whose final slope angles were determined as46°,47°and48°respectively after site investigation about stope hydrology, geology and environmental circumstances had finished. Secondly, the potential hazardous factors affectting slope stability were obtained after the hazard identification of the actual situation of the slope. Finally, fishbone chart about slope accident was drawed by the result of hazard identification2. Based on fuzzy-random reliability analysis, the stability analysis of slope engineering was carried out.Based on the limitations of the classical reliability theory, fuzzy-random reliability theory which considering the engineering uncertainty was selected to analyse the slope engineering. Firstly, slope model with the final slope angle of47°was taken as example to make a selection analysis about membership function, determining the sinusoidal function as membership function. Then after fuzzy-random reliability analysis of these three model, fuzzy-random probability of failure were0.0787、0.0861and0.0962without consideration of seismic loading, while0.0884、0.0902and0.1001with consideration of seismic loading respectively. At last sensitivity analysis on the slope failure probability with cohesion c and friction coefficient f were studied taking46°slope model as an example.3. The network level-set overall analysis and network level-matter-element extension analysis model were selected to integral analyse stability of slope engineering.Evaluation index system, which had16evaluation index of slope stability, was established according to the actual situation of the open-pit slope. The weight value of each evaluation was determined by the analytic network process. Combined with set pair analysis, slope stability evaluation level was determined as a relatively stable level. To avoid failure of set pair analysis, matter-element extension method was selected to analyse stability of slope engineering again, the evaluation grade is relatively stable level.