Firstly got the rock specimens with intrinsic fracture, then carried out seepage tests with high seepage pressure (>1MPa), in order to study the seepage regulation with different seepage pressures and confining pressures. The result stated that the relation between coefficient of permeability and net confining pressure is according to exponential relation. With the same net confining pressure, the coefficient of permeability increases according to the seepage increasing. The loading-unloading tests stated that the crack which experienced higher confining pressure and higher seepage pressure, the seepage speed increases at the second loading that should be resulted from the structural surface damage. Based on theory of seepage-stress coupling and developed fish language of FLAC3D, carried out the numerical simulation according to the test condition, the numerical results are coincident with test. Also analyzed JCR influent for seepage velocity, provided reference for further comprehension for the mechanism of rock crack seepage stress coupling.
Engineering rock is always located in the complex environment between stress field and seepage field such as high and steep slope, deep mining, subsea tunnel and so on. To the subsea tunnel as an example. Its main characteristic is high pore water pressure and large seepage gradient and disturbed by excavation construction. It is easy to cause water-inrush. For example Japanese Seikan Tunnel has happened four water inrush events and caused severe economical losing. So the rock mass seepage flow stress coupling has important social and economic significance.
Single fracture seepage is the base of rock fracture seepage. Early studies firstly got smooth cubic theorem of parallel plate fracture, fracture flow capacity is proportional to gap width (Zhou et al, 2007). The actual rock fracture surface has a degree of roughness and fluctuation. Through a lot of experiments, Barton, Witherspon et al (1980, 1985) corrected the fracture gap width based on the principle of equivalent of seepage flow. Zhou C.B. et al (2008) proposed generalized cubic law based on experiment and theory. Zhang Y.X. et al (2003) studied rough fracture seepage flow per unit width and average gap width between the hypercube and cubic phenomenon. Illustrate the complexity of rock joints and fissures seepage law. Hu D.W. et al (2009) studied the crack of the non-Darcy seepage law. C. Louis (1974) firstly conduct normal stress and seepage coupling test. He say that total stress, the effective normal stress and the relationship between permeability coefficient index.