Abstract：For the excavation damage zone(EDZ) in underground construction，seepage is greatly influenced by the stress in the surrounding rock and the water pressure in cracks. For example，seepage velocity will increase with the water head pressure gradient increasing，and then the seepage becomes nonlinear instead of Darcy flow. So the properties of nonlinear seepage in cracked marble under different hydrostatic pressures and water pressures are focused on. Firstly，the seepage tests are performed using the self-developed temperature-stress-hydraulic coupling test system. According to the test results，the evolutionary law of seepage under different water head pressure gradients can be divided into three stages，namely，steady Darcy seepage，transition from Darcy seepage to nonlinear seepage and nonlinear seepage；and a complete quadratic polynomial is proposed to describe the relationship between water head pressure gradient and seepage velocity. Secondly，the relationship between critical water head pressure gradient and lateral deformation of rock specimen is described by a linear equation based on the deformation data；and then an empirical function is proposed for crack hydraulic aperture and the lateral deformation of specimen. Finally，the evolution of crack hydraulic aperture is studied，which is responsible for the variations of the critical water head pressure gradient，inherent permeability and quadratic term coefficient. Two conclusions are drawn as follows：(1) with the hydrostatic pressure increases，the crack hydraulic aperture reduces，which leads to reduction of the inherent permeability while augments of the critical water head pressure gradient and the quadratic term coefficient；and (2) with the water pressure increases，the crack hydraulic aperture increases，accordingly，the inherent permeability increases，but the critical water head pressure gradient and the quadratic term coefficient reduce.
