Comprehensive Analysis Of Dynamic Destabilization To Roadway Of A Large Scale Across-section In The Crushed Rocks Conditions

The large scale of mined-out-area(LSMA) will be caused inevitably due to excavation of a large scale across-section in crushed rock-mass conditions, and its failure behavior and process is very complex. Those mainly related to the mechanical properties and its deterioration in EDZ(excavation disturbed zone), unstable calamity and abnormality of roof rocks and squeezing and its coupling effect so as to destabilization, delamination upon deepening rocks at roof induced to the local dynamic destabilization. All of process that the micro-scale deformation shifts to large scale manifested non-linear behavior. This brought challenge for engineering unstable control and hazard prevention. Owing to historically seismic-action, the broken rock-mass brought engineering structure destabilization. Yang-Chang-Wan coalfield locates the western seismic-region, joints and cracks of rock-mass are very abundant. The localized of stress in the form of roof falling occurred frequently.The rockmass is soften and fractured, with the maximum cross-section area of 20.4 square meters in Yang-chang-wan Coal Mine. There happened several large scale collapsel instability phenomena in EDZ, with the maximum volume of 216 cubic meters. It restricts the minging production severity and makes mining sequence tensity which is to be solved as soon as possible.Based on the comprehensive investigation of characteristics on regional geology or seismic, the spatial variability of rock-mass, excavation techniques and support models (spatial layout, types, parameters, etc). Firstly, the field engineering geological environment, characteristics of lithologic correlation, mining characters or parameters and dynamical instability of roadway were generally investigated. Secondly, the analysis of the physical simulation and numerical computation as prediction had been adopted. In addition, Acoustic emission(AE),Borehole-Camera and RSM. The field monitoring includes surface deformation, the deep of delamination and its corresponding movement regularity, in-situ experiment and test of bolt-cable mechanical property and engineering quality, etc. All those were intended to seek the mechanism on localization deformation and destabilization in softening and crushed rock-mass conditions at large. This research is very significant to safe mining.