饱和软黏土地基静压管桩承载力时间效应试验研究  

Field test study of time effect on ultimate bearing capacity of jacked pipe pile in soft clay

作　　者：张明义[1] 刘俊伟[2] 于秀霞 

机构地区：[1]青岛理工大学土木工程学院,青岛266033 [2]浙江大学岩土工程研究所,杭州310058 [3]青岛万合建筑设计有限公司,青岛266520

出　　处：《岩土力学》2009年第10期3005-3008,共4页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.50678086)资助

摘　　要：对饱和软黏土地基中的静压管桩进行隔时复压试验发现,复压起动压桩力在沉桩25d后的增长幅度达2.5倍以上,且前期增长较快而后期较慢。理论分析及试验对比证明,利用隔时复压起动压力作为静压桩极限承载力是合理的,而且可以观察到承载力短期内的变化,是进行承载力时效性研究的有效试验途径,分析后认为承载力的增长主要是由于桩侧黏土抗剪强度的提高所致。通过修正得到黏土层桩侧单位面积侧阻力的增长曲线,回归分析得出3种不同的预测公式,对比发现基于对数函数的预测表达式更接近实际情况。In the re-pressed tests with jacked pipe piles in soft clay, it was observed that the re-pressed starting pressure can reach to more than 2.5 times the final pressure for 25 days after finishing the installation; and it increased more rapidly in early period than later. It is reasonable to use start pressure as the ultimate bearing capacity of jacked pile by theoretical analyses and test results, and the changes of beating capacity in short term can be found, which is a effective method to study the time effect. The increase of the bearing capacity mainly resulted from the development of clay shear strength around pile. The increase curves of pile lateral resistance per unit area in clay are confirmed by modification; and three forecasting formulas are derived by regression analysis. By contrast, it is more acceptable to adopt logarithm expression as the formula to forecast bearing capacity of jacked piles.

关 键 词：静压桩 时间效应 隔时复压试验 起动压力 回归分析 

分 类 号：TU442[建筑科学—岩土工程]