Rock Mass Fluid-stress Coupling Process And Coal Seam Floor Water Inrush Mechanism Study

Coal seam floor water inrush hazard is a significant hazard which is a threat to coalmine safety. Coal seam floor water inrush mechanism has always been a hot and difficultproblem in coal mine water hazard control technique study. Water inrush is the result offluid-stress coupling process. Coupled action of fluid and stress was studied as the principleline to reveal coal seam floor water inrush mechanism which has an important theoreticalsignificance and engineering application value.Triaxial tests and permeability tests of fine sandstone, medium sandstone, gritstoneand limestone under different confining pressure and different hydraulic pressure werecarried out. Rock strength and deformation characteristics were obtained. Permeabilitycharacteristics during full stress-strain process were analyzed. Mechnism of how confiningpressure and osmotic pressure difference control rock permeability was put forward.Permeambility dynamic evolution model and fitting fules were established. Characteristicsof acoustic emission during rock failure process were analyzed.Based on the optimized rock engineering system method, coal seam floor water inrshcoupling network was established to reveal coal seam floor water inrush mechanism.Control equations considering the effective stress and deformation of rock mass werederived.Coal seam floor structures were divided to three types which are complete floor,unconnected floor and connected floor. Four water inrush cases were analyzed to explaindifferent fluid-stress coupling model. Post-disaster floor type identification model wasestablished and applicated. The identification result was checked by ananalog simulationmodel. During the analog simulation process, relationship between water pressure andwater inflow was obtained. Coal seam floor pressue and failure characteristics were studiedby COMSOL Multiphysics. Floor structure identification method includes pre-disasteridentification and post-disaster identification is useful to analyze water inrush signs andwater inrush characteristics.Based on experimental study, theoretical analysis, analog simulation, numerialsimulation and cases analysis, the fluid-stress coupling water inrush mechanism wasformed. Coal seam floor structure identification method was established. The new waterinrush mechanism can supply technical support to prevent and control coal mine waterhazard.