【摘要】 基于软件ABAQUS的二次开发平台,引入Byrne修正的Martin和Finn孔压应变模型,并与土体动力黏塑性记忆型嵌套面模型相结合,通过编制Fortran子程序,嵌入到软件ABAQUS中,实现了软件ABAQUS的有效应力算法,对南京片状细砂土的不排水循环三轴试验进行三维数值仿真。通过与循环三轴试验结果的比较,发现数值模拟结果基本上能再现南京片状细砂的不排水循环特性,如不排水循环三轴试验的动应力?应变关系、应变累积、应变软化等;且数值仿真结果较好地反映了试验结果的振动孔压发展特征。研究的意义在于理想三维数值模拟试验能够突破常规的室内土工试验能力及其局限性,这为今后饱和砂土不排水循环特性的宏、细观机理的进一步研究奠定了基础。更多还原

【Abstract】 Based on the ABAQUS finite-element software,the Martin and Finn pore-water pressure-strain model modified by Byrne is inset into the viscous-plastic memorial nested yield surface dynamic constitutive model and the modified constitutive model is developed according to the further developing platform,and an effective stress calculating method is implemented.By means of the three-dimensional numerical model,the cyclic triaxial undrained shear tests of flake-shaped Nanjing fine sand soil are simulated by using ABAQUS with the modified constitutive model.Comparing the numerical simulation results with the cyclic triaxial test results,the undrained dynamic properties of the flake-shaped Nanjing fine sand soil,such as dynamic stress-strain relationship,stain accumulation and stain softening appear.For the development of pore water pressure,good agreement between the results of numerical simulations and laboratory tests is shown.It is shown that the numerical method is feasible for simulating the dynamic stress-strain behavior and the pore-water pressure development of Nanjing fine sand under cyclic loading.The meaning of this research lies on the fact that three-dimensional numerical simulation of cyclic triaxial tests can break through the limits of real lab tests.In addition,it will be helpful to the study of the application of the geotechnical problems in future.更多还原