INFLUENCE OF TENSILE STIFFNESS OF GEOSYNTHETIC REINFORCEMENTS ON PERFORMANCE OF REINFORCED SLOPES

Geosynthetic-reinforced slopes are commonly designed using limit equilibrium methods, which assume geosynthetics and soil reaching a limit equilibrium state simultaneously. The design methodologies only ensure that the slopes have necessary factors of safety for global stability, sliding as well as internal stability by placing sufficiently strong and long geosynthetic reinforcement in the slopes. However, the performance of slopes also depends on deformations especially when structures, such as bridge abutments or buildings, are on the top of the slopes. The deformation related performance is not considered in the limit equilibrium methods. This paper presents a numerical study on reinforced slopes with different tensile stiffness of geosynthetic reinforcements based on the deformation analysis. This study indicates that soil and geosynthetic reinforcements do not necessarily reach the limit equilibrium state at the same time. In other words, the soil may yield first before the geosynthetic reinforcements fully develop their tensile strengths or pullout capacities. The yielding of the soil results in excessive deformations of the slopes. The paper reveals that slopes with different tensile stiffness of geosynthetic reinforcements perform differently in many ways although all the slopes have the same factor of safety against stability by using the simplified Bishop's limit equilibrium design method. This paper investigates the influence of tensile stiffness of geosynthetic reinforcements on horizontal and vertical displacements, maximwm shear strains and their locations, and tensile force distributions along the reinforcements. It is concluded that the tensile stiffness of geosynthtic reinforcements is an important factor that affects the performance of reinforced slopes, therefore, its influence should be taken into account in the design. For the covering abstract see ITRD E117244.