A Numerical Model for Analyses of Flow Through Rock Discontinuities

Water flow in open smooth or rough rock joints, under laminar or turbulent regime, is discussed. The use of a "virtual joint" concept has allowed the development of a numerical model for analyses of non-linear flow in open rock joints by means of the finite element method. The model was verified against published results of laboratory tests on plates of slate and charnockite, carried out to check the validity of existing flow laws. The joints flow analyses, realized to verify the numerical model, have shown very good agreement with the laboratory tests' results. This, together with existing means of determining the joint's opening and relative roughness through field water pressure tests will permit adequate flow analyses of the foundation drainage systems of concrete gravity dams, lying on jointed rock.