Abstract:With the development of the economics, the geosynthetics were widely used in practical engineering like slope and retaining wall. The interface frictional resistance force of the reinforced soil interface is a critical aspect in the design process. In this paper, the progressive failure behavior of the reinforced soil interface under the pullout condition is mainly investigated, pullout process is divided into three phases, pure elastic phase during which follows a elastic relation between the shear stress and shear displacement of the interface; elastic-plastic phase during which a transition point divided the elastic and plastic zones; fully plastic phase. The analytical solution of the tensile force, shear stress and displacement in all stages is given. The results from analysis method are agree well with pullout tests. In addition, investigate the regularity of distribution of the frictional resistance in detail and analyze the influence factors, which include the length of the reinforcement, elasticity modulus of the geosynthetics, shear stiffness and length of plastic zone.