Three dimensional mechanical numerical analyzing on mine pass construction of metal mine
Mine use sublevel caving method, in the production process, the mine pass is an essential ore transport channel, in the production plays an very important role. Therefore the stability of the chute is an important technical support of the mining production and the safety in underground metal mines. Taking a sublevel caving method mining as the research background, Using the MIDAS / GTS finite element software to do numerical analysis of the chute excavation and support of three-dimensional mechanical problems. Results show that: After chute excavation, the wall within 0.3m of a significant displacement, shift several millimeters; different levels of access road excavation, the wall is affected little, But the access road junction with the chute significant displacement, especially with the chute increase the depth of wall the displacement increases; Slip road connecting the wells and different levels of support according to the design parameters, the effect of displacement control of the range of wall displacement and the interchange of access road and chute is significant.
Numerical simulation of structural parameters of large section pillarless sublevel caving of Jinshandian Ore Mine
Aiming at the problem of pillarless sublevel caving structural parameters of the third period mining area of Jinshandian Ore Mine,the possible structural parameters are simulated and analyzed by using sublevel caving simulation system –SLS which is developed by Northeastern University of China and the geotechnical engineer software-FLAC3D which is developed by ITASCA Inc.The numerical experiment indicates that independent advance of ore breaking influences the recovery index evidently,and the independent advance of ore breaking of 3.5-4.5 m has more advantage in recovery index.Also considering the rock blasting effect,the independent advance of ore breaking of 3.5 m is recommended.The numerical simulation of sequential excavation of tunnel groups in a mine block is also carried out.By analyzing the displacements,stresses and plastic zone of excavation simulation,it is concluded that the tunnel groups have satisfactory stability with the designed structural parameters.To sum up,sublevel height of 14 m,drift interval of 16 m,tunnel width of 3.6 m and tunnel height of 3.2 m are reasonable for both the recovery index and the surrounding rock stability.
In situ strength criteria for tunnel design in highly-stressed rock masses
Abstract The selection of rock mass strength parameters and the approach to assessing the mechanical and thermal-mechanical rock mass behaviour around tunnels are important aspects of designing underground openings for a spent nuclear fuel waste repository. This paper demonstrates how strength criteria based on in situ observations can be used to design stable underground openings in rock masses subjected to adverse stress conditions. The findings are based upon work conducted at AECL’s Underground Research Laboratory (URL) regarding rock mass strength around tunnels in sparsely fractured granite.