Two and three-dimensional slope stability analyses of final wall for Miduk mine

Abstract

Background: In this research, Two and three-dimensional slope stability analyses of final slope for Miduk copper mine is investigated by using distinct element code. These analyses were repeated in three positions (dry- drained- wet) and were done for four walls of the mine; including eastern wall, northern wall, western wall and southern wall. Methods: The stability of Miduk copper mine walls were accomplished by distinct element code (UDEC&3DEC). Both 2D and 3D slope stability analyses were performed to establish the representative shear strength parameters to use in the analyses and to examine the differences in the results. The extended Mohr–Coulomb failure criterion was used for analyses. The rock mass was assumed to be permeable and also by the obtained data from surveying, laboratory tests and field observations. Results: The results are as follows: - Water and pore pressure in the faults and main joints were the most important destabilizer factors in these analyses. - The factor of safety after the drainage improved (27–34) % and (20–28) % based on the 3D and 2D slope stability analyses, respectively. - The difference in factors of safety between the 2D and 3D slope stability analyses for the deeper groundwater table (water level in the elevation 2540 on the walls) is less than 7 %. Conclusion: The factors of safety obtained from 2D slope stability analyses are not necessarily more conservative than 3D slope stability analyses. Analyses of the slope after lowering of groundwater table by horizontal drains showed that the factor of safety of the slope has improved tremendously. The differences in factors of safety for 2D and 3D slope stability analyses are greater for low groundwater table as compared with those for high groundwater table. The results illustrated how 3D slope stability analyses have become less daunting to perform and can be incorporated into routine slope designs.