Coupling model of seepage-damage-fracture in fractured rock masses (extended flac3D model) and its appliance

Abstract: By comprehensive use of theory of structural mechanics of rock mass , geometrical damage mechanics and rock fluid mechanics,the model of seepage-damage-fracture coupling (extended FLAC3D model) was established. Baesd on FLAC3D existing computation modules,the programs of seepage-damage-fracture coupling in fractured rock masses were developed with the FISH language.Coupling mechanism of the model of seepage- damage-fracture coupling lies in that hydraulic gradient applies on the stress calculation units as permeate volume strength.Seepage pressure applies on the opening part of cracks as surface force, then lead rocks damage with discontinuous cracks splitting and growth; The cracks growth induce the increase of permeability coefficient, ultimately the change of seepage field.The seepage-damage-fracture coupling analysis on the fractured rock bank slope during the rising of water level in reservoir is shown.The laws of the distribution of the seepage field and rocks damage field evolution were obtained.A preliminary study on deformation of bank slope during the rising of water level in reservoir also was made .Coupling Analysis holds that deformation of bank slope is due to the interaction of increment seepage force and increment uplift force.For the fractured bank slope with the hight relative elevation of water storage , the increase of seepage pressure in fractures lead to damage zone growth with starting-crack and fracture propagation occuring.High seepage pressure lead to damage zone growth in unfavorable fault zone and even transfixion may be the important reasons which result in bank slope instability.