水平向不均匀土对箱基动力阻抗的影响

Effects of horizontally inhomogeneous soil on dynamic impedance functions of box foundation

采用薄层元素法和有限单元法,建立了地基-箱形基础动力相互作用的三维分析模型,该模型可考虑箱形基础周围土的不均匀性影响。利用该模型,分析了水平方向不均匀土对箱形基础的水平和摇摆阻抗的影响。分析了水平方向不均匀土的厚度、剪切弹性模量以及材料阻尼比的影响。分析结果表明:水平方向不均匀土使得箱形基础的各种阻抗均降低,特别是阻抗的虚部。水平方向不均匀土对摇摆阻抗的影响较大。水平方向不均匀土的剪切弹性模量的影响较大而其材料阻尼的影响较小。随着水平方向不均匀土的厚度的增加和基础埋深的增加,其影响增大。

A numerical model for full three-dimensional dynamic soil-box foundation interaction considering the effects of the inhomogeneous soil around the foundation is developed by using the thin layered element method and the finite element method.The horizontal and rocking impedance functions of the box foundation in horizontally inhomogeneous media are compared with those in homogeneous media.The effects of thickness,shear modulus and material damping ratio of the horizontally inhomogeneous soil are studied.The results show that the consideration of the inhomogeneous soil results in reductions in the impedance functions,especially in the imaginary parts.The reductions are prominently in the rocking impedance functions.It is also found that the effects of thickness and shear modulus of the inhomogeneous soil are significant but the effects of the material damping are not significant.The effects of the horizontally inhomogeneous soil increase with the thickness and the embedment depth of the box foundation.