Optimization And Stability Analysis Of Stacking Elements In A Mine Dump

One of the key points in the research of safety science is to eliminate accidents in the bud. In this thesis, we consider various factors influencing the safety of spoilbank before design, and optimize a kind of spoilbank that is safe and economic as well. This thesis is based on the situation of a certain metal mine in Yunnan province planning to build spoilbank No.2, applies theory of limit equilibrium, saturated-unsaturated theory and reliability theory to explore a set of spoilbank design and stability analysis, to achieve stable and efficient dumping and safe production. The main results are as follows:(1) In order to research the influence of different stacking modes and time-space effects on the stability of spoilbank, on the basis of the preliminary design of spoilbank, with spoilbank model formed by different stacking modes as the foundation of analysis, it studies change rules of stacking parameters optimization design and safety coefficient in the process of stacking in different areas. The research results show that security coefficient of multi-step overlay dump is relatively high, thus we should calculate the security coefficient after finishing stacking in the project; when slope toe stacking type in initial period, safety coefficient is low, while it is continuously increasing after 6 ～ 8 steps and becomes safer rather than dangerous. We may flexibly combine the two stacking ways of slope toe stacking type and multi-step overlay dump, and rationally utilize different stacking sequences, slope bottom to resist slip and other space effects to promote the stability of spoilbank.(2) Apply saturated-unsaturated seepage theory and theory of slope stability to analyze slope seepage field after dumping of spoilbank No.2 under the condition of different rainfall infiltration. In order to make rainfall damage rule under the condition of rainfall be more obvious, we especially observe for 10 days after 24 hours continuous heavy rainfall to analyze internal hydraulic distribution and safety coefficient changes within spoilbank; It shows that waste rocks in spoilbank is difficult to store groundwater for its larger permeability coefficient, so as that underground water level will rapidly rise in a short period of time under condition of rainfall and reduce slope stability. Due to underground water at the bottom of slope close to the ground, it is easier to be saturated and form pull-type landslide at slope toe, where the direction of filtration will change as rainfall from paralleling to the residual soil seeping into slope surface seeping, and it is likely to take away the fine sand. If this goes for a long time, it is easier to form soft slope toe, which should be considered seriously.(3) By applying Monte Carlo method, the study explored the slope instability probability which less than safety coefficient under different conditions.