考虑渗流特性的岩体结构面分形特性研究

 裂隙的连通性和密度是影响岩体渗流特性的重要因素。从岩体渗流研究的需要出发，对计算机模拟的岩体裂隙网络，应用分形几何理论，提出考虑裂隙连通性和密度影响的岩体结构面信息维数的计算方法，建立信息维数与岩体渗透系数的关系，进而可以用信息维数和岩体结构面几何参数来直接推求各向异性裂隙岩体的渗透系数张量。工程算例表明：(1) 考虑渗流应力耦合作用时，用容量维数计算的渗透系数比用信息维数计算的值高出2倍多，说明用容量维数计算岩体渗透系数会夸大裂隙岩体的渗透能力；(2) 信息维数能较好地反映裂隙密度对渗流的影响。信息维数越大，表明岩体内连通裂隙数量越多，因而岩体的渗透性就更大一些。

STUDY ON FRACTAL PROPERTY OF FRACTURED ROCK MASS CONSIDERING SEEPAGE CHARACTERISTICS

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.