NON-DARCY SEEPAGE ITERATIVE ALGORITHM FOR CAVING HETEROGENEOUS FLAT FLOW FIELD
采空区流场非达西渗流一种新的迭代算法

To solve the Bachmat nonlinear seepage equation,an iterative algorithm based on the variable permeability Darcy seepage is proposed,considering the goaf characters.Finite element numerical model for nonlinear air leakage flow pattern in caving goaf is established,the flow laws(contours of wind pressure and lines of stream function)and the goaf air leakage intensity distributions(velocity field)are obtained by calculating the air leakage seepage of complex boundary goal,which are found to be consistent with the practical flow patterns.The results indicate that the iterative algorithm converges with oscillation,and the convergence is rapid;in comparison to the Darcy seepage,only the largest wind velocity around the local area near the working face for the nonlinear seepage reduces to 0.61 of the original value,and there is no significant difference in other areas.