抗拔桩的变形与极限承载力计算  

Calculation of displacement and ultimate uplift capacity of tension piles

作　　者：朱碧堂[1] 杨敏[1] 

机构地区：[1]同济大学地下建筑与工程系,上海200092

出　　处：《建筑结构学报》2006年第3期120-129,共10页Journal of Building Structures

基　　金：上海市科委重点基础研究资助项目(02DJ14062);教育部博士点基金资助项目(20020247003)

摘　　要：抗拔桩常用于地下构筑物的抗浮和受较大弯矩作用高耸构筑物的基础。本文推导了基于轴向Winkler地基模型的抗拔桩弹性解答和基于统一极限摩阻分布(由Nc,αs和n三参数描述)的弹塑性有限差分求解方法,编制了相应的程序。应用上述解答和程序,对抗拔桩的变形性状和极限承载力进行了详细地研究,重点讨论了Winkler模型弹簧刚度ks、统一极限摩阻参数Nc、αs和n,以及上覆土层对抗拔桩的变形和极限承载力的影响。结果表明,Nc和ks对抗拔桩的弹塑性变形影响显著,而极限承载力主要取决于Nc值和上覆土层厚度。Tension piles are widely used for resisting uplift loads of underground structures such as deep basements and underground transformer substation, and as foundations for tall buildings subjected to high bending moments. Based on the axial Winkler foundation model, both elastic closed form solutions and elasto-plastic solutions using a unified ultimate skin friction along pile shaft in conjunction with finite difference methods are presented in this paper. Accordingly, a spreadsheet program is developed. Using these solutions and the program, displacement and ultimate uplift capacity of tension piles are examined in detail; effects of modulus of subgrade reaction ks for the Winkler model, unified ultimate skin friction coefficients No, α s, n and excavation depth on pile displacement and ultimate uplift capacity are investigated. It indicates that the values of Nc and ks have significant influence on the displacement, while uplift capacity of tension piles is dominated by value of Nc and overburden stress.

关 键 词：抗拔桩 统一极限摩阻 弹塑性分析 极限承载力 

分 类 号：TU473.1[建筑科学—结构工程]