Papers by Keyword: Numerical Simulation Test

Abstract: Significant geological factor of coal occurrence is layered structure of coal measures overburden rock, and bedrock sand-shale ratio is a key element of coal measures overburden rock layered structure. On the background of geological occurrence conditions of 2^-2 coal in Yushen coal mining area, the sandstone layer, sandstone average thickness and sand-shale ratio are taken as variables to build the 18 different types of layered structure models. On this basis, basic law of coal measures bedrock sand-shale ratios which is a key characteristic of layered structure impacting mining subsidence is mainly studied by using numerical simulation method. The results show that: firstly, in spite of any condition of sandstone layer coefficient subsidence coefficient always decrease with the increase of sand-shale ratios. However, the effect of sand-shale ratios on subsidence coefficient continuously decreased with the increasing of sandstone layer coefficient. Secondly, when the sandstone layer coefficient is less than 70%, the different sand-shale ratios have significant influence on the subsidence coefficient, and when the sandstone layer coefficient is more than 90%, subsidence coefficients corresponding to different sand-shale ratios show obvious convergence characteristics. The gap between each other is only 1%~2%. Thirdly, taking the subsidence coefficient corresponding to the sand-shale ratio is 6:4 as reference, the curves about the rate of decrease in subsidence coefficient is set up when the sand-shale ratio is 7:3 or 8:2, and the fitting equations are presented on the basis of Log3P1 mathematical model.

Abstract: On the basis of suitable arrangement for the special stress surrounding and parameters selection, Realistic Failure Process Analysis 2-D (RFPA2D) numerical simulation of extra-thick coal seams’ displacement and failure is carried out. It’s proved that the numerical simulation results are consistent with the in-sit measurement results of top coal’s advance supporting stress and deep-hole displacement. So application of RFPA2D in sub-level caving mining extra-thick coal seams is reliable. It’s also proved that application of RFPA2D in sub-level caving mining can do great help to study the nature of top coal’s displacement, fragmentation and failure process of extra-thick coal seams. As the top coal’s displacement and failure situation under certain circumstance can be forecasted by RFPA2D numerical simulation, the most suitable top coal thickness under certain circumstance can be predicted by RFPA2D numerical simulation test, which can do great benefit to extra-thick coal seams’ safe and high efficient mining.