中文摘要：

为分析加筋材料的抗弯刚度对加筋性能的影响，加筋材料采用梁单元形式。基于动态松弛法，通过定义梁单元的刚度矩阵，求解内力矢量，随后定义虚拟质量密度而建立总质量矩阵，将加筋材料的梁单元有限元模型嵌入到已有的动态松弛法求解程序中。通过对简支梁的简单加载模拟验证了该梁单元模型的准确性能。随后，将该有限元模型与已有的动态松弛法计算程序结合（含砂土本构及弱面单元模型），对加筋砂土地基室内模型试验进行了数值模拟。将梁单元的模拟结果与杆单元（梁单元的特例）模拟结果进行了比较，并分别探讨了抗拉刚度和抗弯刚度对加筋砂土地基承载性能的影响。结果表明：抗拉刚度对承载能力的影响较小；抗弯刚度对承载力的影响程度与加筋材料的布置形式有关，特别是当加筋砂土中出现剪切带以后，其影响逐渐增大。因此，在分析加筋砂土结构的增强机制时，建议采用梁单元（具有一定的抗弯刚度）对加筋材料进行模拟。

英文摘要：

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 stiff ess） in the simulation procedure.