توصيفگر ها :
معدنكاري زيرزميني , استخراج از طبقات فرعي , توالي استخراج , پايداري فضاهاي زيرزميني , روش عددي
چكيده انگليسي :
In underground mines that perform drilling and mining operations by extracting from sub-layers, in most cases, several underground spaces with different arrangements are created side by side, whose influence on each other may cause disturbances in their stability, and in addition Therefore, the excavation of these spaces leads to settlement on the surface of the earth, as a result, surface and subsurface structures may be damaged. In the mines that proceed with the method of extraction from the sub-grades, the extraction steps are of particular importance in terms of the economic aspect and the stability of the underground space for the mine; The issue of drilling sequences and the interaction of underground spaces in civil structures has been studied abundantly, but this issue has been neglected in mines. In this research, the stability of underground spaces and the settlement resulting from the excavation of tunnels, ramps, and high and low waists of mineral material in Faizabad Nain lead and zinc mine with different extraction sequences have been done. For this purpose, to investigate the effects of the underground mining sequence on the stability of underground structures in this research, two scenarios were considered separately, in the first scenario, the characteristics of the upper waist and lower waist and the mineral substance for GSI = 65 were calculated and the effects of the extraction steps in The lengths of 10, 15 and 20 meters were examined and in the second scenario, using the Taguchi method in MINITAB software, a number of tests were conducted based on different parameters of upper waist, lower waist, mineral matter and steps of 10, 15 and 20 meters. Three different levels of GSI = 45, 55, 65 were designed and investigated. In this research, using the finite difference numerical method by FLAC3D software, the stability of underground spaces, including waist-high, access tunnels and vertical bearing on the layer along with the settlement resulting from their excavation, was analyzed. The geometry of the model was designed by Catia and Rhino software, and its output for FLAC3D was done by Gridel software. In general, in this research, the results of numerical modeling showed that the greatest effect of mineral extraction is on the stability of the upper waist area, because the mineral is located under this area and is directly related to it. Also, according to the amount of displacement at different levels for different extraction steps, as well as the process of changing the values of the plastic surface and the ratio of stress to resistance, it can be found that the lower the extraction step, the lower the maximum displacement and the greater the stability of the underground space. If the amount of extraction step increases, the amount of maximum displacement will be higher and the stability of the underground space will be lower. Finally, in general, it can be concluded that in the Faiz Abad underground lead and zinc mine, due to the resistance of the rock, the change in the drilling step does not have much effect on the stability of the structures and settlement. This is such that no significant change is observed in the displacements within the different sequences of mineral drilling.
Keyword: underground mining, extraction from sub-levels, extraction sequence, stability of underground spaces, numerical method
