Abstract:Based on laboratory data of unsaturated flow in clay,the constitutive model of unsaturated flow coupled model for clay considering plastic strain hardening and Hoek-Brown model is applied to simulate the swelling and shrinking behavior of clay shaft during excavation,concrete lining stage and long time ventilation. With the help of numerical simulation,the flow process in clay from initial saturated to desaturated and then to resaturated is stated. Furthermore,the sensitivity analysis of Biot coefficient,capillary pressure and water relative permeability with saturation degree is discussed;and the results show that the hydraulic parameters have effects on unsaturated zone in surrounding rock mass,especially the water relative permeability,while the mechanical behavior of clay has low effect on unsaturated flow law in surrounding rock mass.