Study On Optimum Design Of Stope Structure Parameters And Reliability Analysis

The determination of favorable stope structure parameters is the key issue of safety and high efficiency production of mine, which is also the routine work of mining design practice. When determining the specific engineering designed parameters, the multi-scheme evaluation and analysis are to be used, for which diversified ways are applied to analyze the influence rules of different factors. On the engineering background of the parameters design of Xinli district of Sanshandao Gold Mine, the geological situation of construction of the mining area is analyzed in detail. The comprehensive methods of mechanical analysis, numerical simulation and reliability analysis are applied for the design of stope structure parameters. A series of different arrangement of stope structure parameter are analyzed through the methods, to study the stress and strain distribution of stope and surrounding rock of different situation, thus the best combination of stope structure parameters can be determined. The main research and achievements are as follows:(1) The detailed engineering geological investigation was carried out to obtain the law of in-situ stress field, joint fissure distribution and geological groups. Then the range of the stope structure parameters was initially designed from the aspect of mechanical analysis.(2) The FEM software ANSYS was used for the first numerical simulation of mine room exploitation process, considering the dynamic effect of step by step excavation. Through the comparative analysis of stress and strain of different excavation situation of during the mining process, the most dangerous excavation step was determined. Then the step could be used for the analysis of stope structure optimum selection. Thus the design results were in demand of the stope structure stability of the key step.(3) The three-dimension geo-mechanical model was established for the consequent simulation analysis. The 3 different pillar section size and 4 pillar interval space were selected. And the 12 different combinations of the two parameters were used for the simulation. The 12 sets of different stress and displacement distribution were calculated. Through the analysis of the 12 calculated results, the 5 sets were selected for the possible stope structure parameters combined with the aspects of mining technical conditions and economy.(4) The reliability of the initially determined parameters of numerical simulation was analyzed. The analysis focused on the reliability of the pillar function. The implicit performance function of the limit state of pillar was established, which took into account of the three main factors influencing the pillar strength of the random of rock mass strength, pillar size and rock mass mechanical characteristics. On the basis of the reliability and failure probability results, combined with the requirements of mining technology and economy, the ultimate structure parameters are that the pillar section size is 4m×4m and pillar interval space 12m.