剪胀角对地基极限承载力影响的有限元极限分析  

Effect of shear dilatancy angle on ultimate bearing capacity of foundation by FEM limit analysis

作　　者：赵金勇[1] 蒋刚[1] 杨磊[1] 宰金珉[1] 王旭东[1] 

机构地区：[1]南京工业大学土木工程学院,江苏南京210009

出　　处：《南京工业大学学报（自然科学版）》2008年第5期28-32,共5页Journal of Nanjing Tech University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(50478005);江苏省自然科学基金资助项目(BK2004420)

摘　　要：采用有限元增量加载法计算地基极限承载力,分析不同剪胀角取值对计算结果的影响,结果表明,剪胀角对地基极限承载力的影响大致可以分为震荡段和稳定段2个阶段.在震荡段内,地基极限承载力随剪胀角增加呈震荡跳跃特征,且对单元类型和网格疏密程度敏感;在平稳段内,地基极限承载力随剪胀角的变化不大,与Prandlt理论解一致.剪胀角对基底附近塑性区的发展分布和破坏模式亦有显著影响,随剪胀角的增大塑性区分布逐渐扩大.当剪胀角小于某特定值时,地基破坏表现为基底土体的冲切刺入,类似于地基的冲剪破坏;当剪胀角大于某特定值时,塑性区分布类似于Prandlt破坏机构,有明显的主动区、过渡区和被动区.The effect of shear dilatancy angle on ultimate bearing capacity of foundation was analyzed by elastoplastic finite element method （FEM） with step laoding. The results show that the effect can be separated into fluctuative phase, and steady phase. At the fluctuative phase, the ultimate hearing capacity of foundation is fluctuative with the shear dilatancy angle increase, and the results are depended on element type and element density. At the steady phase, the ultimate bearing capacity has little change with shear dilatancy angle changes, and is close to the solution of the classical Prandtl method. The shear dilatancy angle obviously affects plastic zone on the foundation. As the shear dilatancy angle is less than certain angle, the foundation penetrates into the ground, being similar to punching failure; as the shear dilatancy angle is greater than certain angle and the distribution of the plastic zone is similar to that of Prandtl pattern, the obvious active zone, transitional zone and passive zone can be observed.

关 键 词：剪胀角 屈服准则 地基极限承载力 有限元极限分析 破坏模式 

分 类 号：TU470.1[建筑科学—结构工程] TU457[建筑科学—土工工程]