Study On The Underground Structure Stability And Reliability Based On The Re-Constitutional Mining Environment

The deposit of the Kelatongke Copper-Nickel Mine possesses some characteristics such as poor rockmass, high-value and deep-lying, and the reconstruction of mined-out environment and continuous caving method with subsequent backfilling is applied to exploit it. The innovative technology of the mining method is the new working procedure. First constructing an artificial structure around the ore body by the filling technology, strata control technology and grouting technology; and then adopting the induction caving method to achieve high efficiency mining; in the end backfilling the stope with the waste tailings after drawing out the ore. Generally speaking, the artificial structure is the key technology in reconstructing the mining environment for which affects directly the working safe and mining cost. Based on the complex and indefinite of the characters of rockmass, stress condition, as well as the process of construction, it is necessary to study the stability and reliability of the artificial structure. This paper makes a depth research on it and obtains such achievements:(1) Through carrying out the detailed investigation of the engineering geomechanic, the information of jointed in rockmass, rock stresses, hydrogeology and geological engineering rockmass are gained, also the planning and programming of project construction is made based on such information.(2) This study simulates the two caving modes' mining process, compares them between the stope's stability and ore particle size, selects the side-extruding caving mode as the best caving method.(3) Using the displacement and plastic zone as the criterion, the stability of artificial structure is analyzed by the FLAC3D software, which optimizes the stope structural parameters and mining sequence, as well as propose the practical and feasible control measures. The size of the artificial structure is designed: the thickness of roof 9m, the width of pillar is 6m, as well as the thickness of bottom structure is 8m.(4) The software of NESSUS is applied to analyze the reliability of the artificial structure. After adjusting some important variables and calculating again, the reliability value of the structure get to 0.967374, which meets the engineering design demands.