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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。
In order to analyze the influence of the flexural rigidity of the stiffened material on the stiffener performance, the stiffened material is in the form of beam elements. Based on the dynamic relaxation method, the internal force vector is solved by defining the stiffness matrix of the beam element, and then the virtual mass density is defined to establish the total mass matrix. The finite element model of the beam element embedded with stiffened material is embedded into the existing dynamic relaxation method. The accuracy of the beam element model is verified by a simple loading simulation of simply supported beams. Subsequently, this finite element model was combined with the existing dynamic relaxation method (including the constitutive model of sand and weak element) to simulate the indoor model test of reinforced sand foundation. The simulation results of beam elements are compared with those of rod elements (the special case of beam elements), and the effects of tensile stiffness and flexural rigidity on the bearing capacity of the reinforced sand foundation are discussed respectively. The results show that the effect of tensile stiffness on the bearing capacity is small. The influence of the bending stiffness on the bearing capacity is related to the arrangement of reinforcement material. Especially when the shear band appears in the reinforced sand, Big. Therefore, when analyzing the reinforcing mechanism of the reinforced sand structure, it is suggested to simulate the reinforced material with the beam element (with certain bending rigidity).