Stability Analysis Of Fullly-Mechanized Caving Tunnel And Its Valuation In Chaos Dynamic Ways

With the continual progress of mining technology, the full-mechanized caving technique has been widely spreaded and applied in thick seam extraction in our country. Requirments for the stability and support of the roadway' s surrounding rock is more strict for the thickness of extraction once is large and the concentration of extraction stress and the large affected scope of full-mechanized caving method. Research of the roadway stability and supporting mechanisation is still remains at the level of Newton' s definition thesis, in fact, the surrounding rock motation of the roadway appears clearly nonlinear dynamic feature.This dissertation set Nantun colliery as the protomodel. Firstly, the motation of the tunnel surrounding rock was analyzed by numerical simulation in decrete element method, the roadway' s stability under different pillar size and support conditions was analyzed in many factors such as the subsidence of the roof, displace of the pillar surface, horizantal stress in the roof, vertical and horizantal stress in the pillar and damage element of the surrounding rock, the following conclusion can be reached:the size of pillar and support condition have great effects on the displace, stress and damage area of fully-mechanized caving roadway surrounding rock;with the pillar size be larger, the stress area that the roadway be located change from low stress area to peak stress area and final be in original rock stress area;the undulating scope and level of stress in fully-mechanized caving roadway surrounding rock can be effectively weakened by bolts supports;the gathered data that describe the stability of fully-mechanized caving roadway surrounding rock is the time series changing with the time which have typical nonlinear feature.Secondly, according to the data gathered in the numerical simulation, the power spectrum analysis, fractal dimension and Lyapunov exponent calculation for the time series were carried out;when the pillar size is specially small or the roadway was located in the peak support stress area, the power spectrun have the feature of continuity, noise background and wide peak;the fractal dimension value that caluated from each group data all are fraction. the variable number that describe the system dynamic state was determined as 3 with the utility of...