Abstract: To analyze the influence of bending stiffness of reinforcement on the bearing capacity of reinforced soil structures, the beam element form is applied to modeling for reinforcement. Based on the dynamic relaxation (DR) method, the finite element model of beam element simulating reinforcement is presented. Firstly, the beam element stiffness matrix is constructed and the solution to internal force vector is obtained. Then, the fictitious mass density is defined just for numerical purposes and a mass matrix is established. The beam model is embedded in the existing dynamic relaxation calculation program. To validate the performance and accuracy of the beam element model , the loading simulation of simple beam is conducted. Subsequently model, the numerical study for the reinforced sandy ground physical model test is carried out by combining the beam element model and the DR calculation program (including the sand constitutive and the interface models). The comparison of simulation results between the beam element model and bar element model are conducted. The influences of tensile stiffness and bending stiffness on the bearing capacities of reinforced sand foundation are discussed respectively. The simulation results show that the tensile stiffness has little effect on the bearing capacity of the reinforced sand foundation. The influence of bending stiffness on bearing capacity is related to the reinforcement layout; especially when the shear band occurs in the reinforced sand structures, the impact will increase. Thus, to analyze the reinforced mechanism of reinforced sand structures, the beam element is recommended (with bending stiffness) in the simulation procedure.

Key words: reinforced sand, reinforced material, dynamic relaxation method, finite element method(FEM), beam element, stiffness effect