Non-Darcy Seepage Theory And Its Engineering Application

At present,most of the engineering application of the seepage problem is based on the linear Darcy's law,but the actual groundwater flow in porous medium is affected by various factors,the flow is more complex,the actual flow is nonlinear.A lot of test data and monitoring data also confirmed the existence a lot of deviation from Darcy flow phenomenon,Therefore,if the linear Darcy's law is still used,there is a large error in the calculated water head distribution and seepage flow,There are some differences in the description of seepage movement,And the Seepage flow exists in various fields of engineering,and many engineering accidents are caused by seepage,in particular,it has a great influence on the safety of the project in some special circumstances.Therefore,the study of the deviation from Darcy seepage has important and far-reaching significance.In this paper,based on the analysis of the basic theory of seepage,and based on the basic principle of seepage mechanics,this paper has carried out the following work;(1)An overview of the basic principle of seepage,Darcy's law and the non Darcy flow theory are summarized and analyzed the causes of non Darcy seepage,and the seepage analysis method,summarized the seepage numerical calculation principle,Darcy seepage basic differential equation is derived.(2)According to the analysis of non Darcy flow,In view of the nonlinear seepage flow equation,combined with the seepage condition of earth rock dam,t In this paper,the differential equation of non Darcy flow with gravity and inertia force is derived in the form of fluid potential,and The finite volume method is used to solve the equation(3)In this paper,the calculation program was compiled by FORTRAN language,The solid modeling of the object of study by using ANSYS software,The unit node information is imported into the SP program's pre-processing module and the unit topology relation file is generated.The program is calculated and the results are calculated by TECPLOT software.(4)According toprevious research results and the measured data,We select typical examples to verify the rationality and accuracy of the equation.(5)Aake the actual dam project as an example,It carries out numerical simulation of non Darcy flow by using SP program,The simulation results of Darcy flow and non Darcy flow simulation are compared and analyzed.Thus,Non Darcy seepage formula is used to calculate,The free surface will be increased,downstream of the dam overflow point will be slightly increased,the hydraulic gradient increases,the more obvious,and with the increase of the upstream water head and hydraulic gradient increase,In this paper,the seepage dischargeis reduced by non Darcy seepage formula,the seepage discharge is reduced,The phenomenon of non Darcy percolation is more obvious...