摘要
对于横观各向同性软基上深埋式大圆筒结构的承载力,假定大圆筒结构绕筒体内中轴线上某点发生转动失稳,靠近泥面附近形成潜在破坏楔体,而筒底部形成球形滑裂面,以此为基础,基于塑性极限分析理论考虑软土强度的各向异性效应,提出一种改进的极限分析上限解法。根据加载过程中筒体前主动侧土体与筒体间界面的脱离或黏结等两种不同的接触状态,将可能的破坏机制划分为仅在筒后被动侧形成楔体形破坏的单面破坏机制和在筒前主动侧与筒后被动侧均形成楔体形破坏的双面破坏机制。利用大型通用有限元分析软件ABAQUS,采用基于Hill屈服准则的理想弹塑性本构模型,对软基上大圆筒结构的水平承载力进行三维弹塑性数值分析,由此所得到的破坏模式及大圆筒结构水平承载力与所提出的改进的极限分析上限解法基本一致。进而通过变动参数的对比分析,探讨K0固结条件下软黏土不排水抗剪强度的各向异性、荷载作用点高度及结构-土界面摩擦折减系数等对大圆筒结构承载力的影响。
A modified three-dimensional plastic limit analysis method of bearing capacity of large-diameter cylindrical structure in cross-isotropic soft ground is presented.The most likely failure mechanism is assumed to be of a composite rupture surface which is composed of an individual wedge in passive zone or two wedges in both active and passive zones near the mudline,depending on separation or bonding state at the interface between the cylindrical structure and neighboring soils in the active wedge,and a truncated spherical slip surface at the base of the cylinder when the structure tends to overturn around a point which is located on the symmetry axis of the structure.The cylindrical structure and soil interaction system under consideration is also numerically analyzed by the finite element method with software ABAQUS,in which the soil is assumed to obey the Hill′s yield criterion.Both the failure mechanism assumed and the plastic limit analysis predictions are validated by numerical computations based on FEM.The effects of strength anisotropy of soil,height of loading action point above the mudline and coefficient of friction of the soil-structure interface on bearing capacity of deeply-embedded large-diameter cylindrical structure are examined through comparative analyses.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2007年第1期94-101,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50579006
50179006)
国家自然科学基金重点项目(50639010)
跨世纪优秀人才培养计划研究基金项目(教技函[1999]2号)
关键词
土力学
大圆筒结构
软基
横观各向同性
极限分析上限解法
有限元分析
soil mechanicsl
arge-diameter cylindrical structure
soft soil
cross-isotropy
upper-bound procedure of limit analysis
finite element analysis
