摘要
针对地基工程复杂的随机非线性力学增益,基于黏塑性非线性随机有限元优势,借助Mohr-Coulomb破坏准则下的黏性拟时间步,推导在三维及平面应变条件下黏塑性非线性随机有限元的本构关系式,建立基于全量理论的黏塑性非线性随机有限元列式.在Naylor孔隙水压理论基础上,提出考虑各向同性及各向异性孔压条件的土体介质黏塑性非线性随机本构模型.以施工期三层复合地基为例,分别针对关联及非关联流动法则2种工况,研究地基在增量加载条件下的位移、应力、黏塑性应变、孔隙水压等矢量场的随机数字特征,以及地基在各个加载时期的可靠度情况.结果表明,在复杂工况下复合地基中有效应力及孔隙水压的数字特征与可靠指标分布的内在联系紧密;由非关联到关联流动法则,有效应力增加,孔压减小,同时随着孔压变异下降、可靠指标显著提高,由此形成在随机数学覆盖下完整的非线性数学模型.
The three-dimensional constitutional relationship and the plane strain constitutional relationship under the viscous-plastic non-linear stochastic numerical model were induced by the help of Mohr-Coulomb failure criterion viscous quasi-time step form.Thereby,complicated characteristics of stochastic non-linear mechanics gain on foundation engineering were studied based on key merits of the viscous-plastic non-linear stochastic finite element method.Furthermore,founded here was total strain theoretic viscous-plastic non-linear stochastic finite element algorithm.Porous medium viscous-plastic non-linear stochastic constitution in joint with isotropic as well as anisotropic porous pressure was invited on the basis of Naylor super static porous pressure theory.With the application to a three strata composite foundation during construction period,the random vector fields of displacement,stress,viscous-plastic strain,porous pressure,in addition to the reliability distribution of the foundation on every loading phase were researched under two working behaviors respectively,namely,associated flow rule and unassociated flow rule.The comprehensive studies show that the reliability index has a close relation with the stochastic characteristics of the effective stress and porous pressure of the composite foundation under complex work behaviors;and that with the range from unassociated flow rule to associated one,the effective stress escalates under the decrease of expectation and variation on porous pressure while the reliability index accumulating,on which,the precise nonlinear numerical model under random mathematical coverage is formed.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2010年第4期798-805,共8页
Journal of Zhejiang University：Engineering Science
基金
国家自然科学基金资助项目(50379046)
教育部博士点基金资助项目(A50221)
关键词
黏性拟时间步
黏塑性非线性
随机有限元方法
层状地基
流动法则
孔隙压力特征
地基可靠度
viscous quasi-time step
viscous-plastic non-linearity
stochastic finite element method
stratified foundation
flow rule
porous pressure characteristics
foundation reliability
