Fluid-solid Coupling Numerical Model of Equivalent Continuous Medium for Rockmass Under Mining and Its Application

It is importance to research the seepage law of excavated rockmass for preventing and controlling of water hazards, an equivalent porous medium conductivity for rockmass under coal mining was deduced according to cubic law, in which the strain was considered as a parameter. Basing on FLAC(3D), an equivalent continuous medium numerical model was developed with the fluid-solid coupling effect was sonsidered, the calculating programme was built with FISH lanuage. The study results indicate that, in the initial stages, the increasing permeability zones in the excavated rockmass has the shape of "M"in the roof and "W"in the floor, the conductive fracture formed when the two increasing permeability zones intersect in the aquifer and the roof. The pore pressure change periodically in the aquifer, when water bursting the pressure reach the ultimate value and then falling rapidlly, the conductivity taking the strain as a parameter can describe the seepage law of rock mass under mining exactly.