考虑应变软化的T-bar承载力CEL有限元分析

CEL Finite Element Analysis of T-bar Bearing Capacity with Strain Softening

通过欧拉-拉格朗日(Coupled Eulerian-Lagrangian,CEL)大变形有限元对不考虑应变软化的T形触探仪(T-bar)承载力系数进行计算,其计算结果与已有塑性理论解和RITSS(Remeshing and Interpolation with Small Strain,即在小变形有限元的基础上通过网格重剖分和应力插值技术实现大变形有限元分析)的计算结果均吻合较好,验证了CEL计算模型的可靠性。在ABAQUS有限元平台的基础上进行二次开发,编写应变软化子程序计算出考虑应变软化的T-bar承载力系数,其计算结果与RITSS吻合较好,验证了应变软化子程序的可靠性。对T-bar周围土体的软化程度和流动机制分析发现,应变软化使土体抗剪强度减小的同时还改变了土体的流动机制,这两个因素的综合作用导致T-bar的承载力系数减小,从而揭示了应变软化对T-bar承载力系数的影响机理。

The T-bar bearing capacity coefficients without considering strain softening was calculated by CEL（ Coupled Eulerian- Lagrangian）,a large deformation finite element method. The results from CEL method are in good agreement with the results of existing plastic theoretical solutions and RITSS（ remeshing and interpolation with small strain,in which the large deformation finite element analysis is realized by remeshing technique and stress interpolation technique on the basis of small deformation finite element）,thus the reliability of the CEL calculation model is verified. Based on the ABAQUS finite element platform,we developed a new compile strain softening subroutine to calculate T-bar bearing capacity coefficient considering strain softening. The results by strain softening subroutine are in good agreement with the results of RITSS,so the reliability of the strain softening subroutine is verified. By analyzing the degree of softening and flow mechanism of soil around T-bar,it can be found that strain softening not only reduces the shear strength of soil,but also changes its flow mechanism. The combined effects of these two factors lead to the decrease of the bearing capacity coefficient of T-bar. So,the effect mechanism of strain softening on the bearing capacity coefficient of T-bar was revealed.