软土地基中扩底抗拔中长桩的极限承载力分析  

Analysis of uplift capacity of long enlarged-base pile in soft soil ground

作　　者：郦建俊[1,2] 黄茂松[1,3] 王卫东[4] 陈峥[5] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]上海建科工程项目管理有限公司,上海200032 [3]同济大学岩土及地下工程教育部重点实验室 [4]华东建筑设计研究院,上海200002 [5]华东电力设计院,上海200063

出　　处：《岩土力学》2009年第9期2643-2650,2666,共9页Rock and Soil Mechanics

基　　金：上海市科委科技攻关重点项目(052112010)

摘　　要：扩底抗拔桩的研究和应用以短桩居多,并且大都以砂土或软岩为持力层,对于软土地基中扩底抗拔桩的承载力研究较少。基于扩大头局部剪切滑移面假设的极限平衡法,推导出扩底抗拔中长桩在分层地基中极限承载力的简化计算公式;结合有关工程实例的原位试桩结果,对扩大头影响高度进行了确定,同时还探讨了所提出方法在超长桩中的适用性。研究结果表明,提出的简化分析方法能合理地揭示上海软土地区扩底抗拔中长桩的破坏机制,并获得承载力变化的一般规律。Determination of ultimate uplift capacity for enlarged-base pile plays a dominant role in engineering design. Resorting to limit equilibrium method based on local cutting slippage surface, a new simple formula of uplift capacity of enlarged-base pile in soft clay is deduced. Calculated results by the proposed formula have a good accordance with field test data. Based on above analysis approach, range of enlarged base is gained combined with the in situ test and engineering example. Finally, the analysis approach is applied to long enlarged-base pile and some useful conclusions are drawn： Failure mechanism of enlarged-base pile embedded in soft clay can be interpreted rationally with local cutting slippage surface; Range of enlarged base is related to pile radii and embedded depth.

关 键 词：扩底抗拔桩 局部剪切滑移面 极限平衡法 极限承载力 

分 类 号：TU473.1[建筑科学—结构工程]