Study On Slope Angle Optimization Of Complex High And Steep Rock Slope

After thirty years’excavation, the mining work of Chengmenshan has entered the third stage of company schedule. The the slope will be higher than400meters in the end of the third mining stage. A lot of work was done to analyse the slope stability. The rock mass mechanic parameters were determined based on the field survey and a series of rock mechanic experiments. The analysis process of DIMINE-AutoCAD-SLIDE was built. The underground water, dynamic of earthquak e and the gravity of rockmass were considered during the process. The most critical slip surface and the minimum safety factor were searched by the way of auto-searching. The parameters of slope were optimized based on all the work at last. The main research work of the paper is summarized as below.(1) During several times of field survey to the open-pit excavation slope, the joint parameters of rockmass were measured and the joint density figure of every survy spot was made. A lot of rock samples of every lithologic character and Huni were collected to test the geology mechanic parameters. Combined with the history study, the parameters of almost all kinds of lithologic characters were determined(2) A series of experiments including direct shear and consolidation were conducted to study the characters of Huni. The correlation between the height of slope and angle of slope was analysed, and a comprehensive result was given. The angle of were19～23°and25°to Huni slope and Quaternary system soil slope respectively.(3) A digital geology model of the mining area was built using DIMINE a digital modeling software. The Simplified Bishop Method, Spencer Method and Morgenstern-Price were adopted to calculate the factor of safety. The most critical slip surface and the minimum safety factor were searched by the way of auto-searching. The result showed that the failure modes of the slope were mainly integral sliding. All the result provided theoretical support to the optimization of the slope.(4) Four kinds of operating condition of slope were compared during the analysis. The analysis results showed that the safety factor under the worst operating condition of most slopes was1.1or even lower. Considering the complicated geology condition of Chengmenshan, the permitted safety factor of1.20was choosed as the standard safety factor to optimize the slope parameters at last.