STUDY ON FRACTAL PROPERTY OF FRACTURED ROCK MASS CONSIDERING SEEPAGE CHARACTERISTICS
ZHANG Yanhong1,2,CHAI Junrui1,3
(1. College of Hydroelectric Engineering,Xi¢an University of Technology,Xi¢an,Shaanxi 710048,China;2. Department of Hydroelectric Engineering,Gansu Agricultural University,Lanzhou,Gansu 730070,China;3. College of Civil and Hydroelectric Engineering,China Three Gorges University,Yichang,Hubei 443002,China)
Abstract:Both the fissure connectivity and density are the important influencing factors of seepage characteristics in fractured rock mass. In order to meet the needs of seepage study in fractured rock mass,based on the theory of fractal geometry,the method to calculate fractal dimension of fractured rock mass considering fissures connectivity and their density after simulating out the fissures network by Monte Carlo technique is proposed. Moreover,the relationship between information dimension and permeability coefficient of rock mass is presented,so the permeability tensor of anisotropic fractured rock can be deduced directly by its geometry parameters and information dimension. Further results from project case as follows:(1) when considering the role of seepage coupling with stress,the rock mass permeability given by capacity dimension is 2 times more than that by information dimension,it shows that calculating permeability with capacity dimension will exaggerate the volume of seepage in rock mass;and (2) the value of information dimension can accurately describe how the fissure density affects fluid flow in fractured rock mass,because the bigger value of information dimension always shows the more quantity of interconnected fissures and the more permeability capacity in rock mass.