), 徐子涵 地下建筑与工程系, 上海 200092
收稿日期:2019-12-03出版日期:2021-04-28发布日期:2021-04-30作者简介:李镜培(1963-),男,江西省赣州市人,教授,博士生导师,主要研究方向为岩土力学及桩基础工程.电话(Tel.):13901656003;E-mail: 基金资助:国家自然科学基金资助项目(41972274)Prediction of Ultimate Bearing Capacity of Long-Term Loaded Piles
LI Jingpei(), XU Zihan Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China
Received:2019-12-03Online:2021-04-28Published:2021-04-30摘要/Abstract
摘要： 为准确预测长期受荷桩的极限承载力,对桩基承载力时间效应经验公式的不足进行了探讨,并基于天然饱和黏土地基静压桩承载力时效性研究的理论成果,对经历长期受荷的旧桩承载力的影响因素进行了分析.在此基础上,采用相关研究机构的桩基承载试验数据开展分析,提出了考虑桩基承载力时间效应的静压桩极限承载力计算公式;提出了桩侧阻力时效系数γ,探讨了影响γ的一些关键因素,并基于试验数据提出了采用土体性质参数计算γ的方法.通过现场试验对本文方法的准确性进行了验证.研究结果表明:采用γ可对现行规范中单桩承载力计算公式进行修正,在保证安全性的前提下,获得更高的旧桩单桩承载力设计值;而γ则可采用不排水抗剪强度Su 及塑性指数IP进行预测.
关键词: 旧桩, 极限承载力, 时效系数, 不排水抗剪强度, 现场试验
Abstract: To predict the ultimate bearing capacity of long-term loaded piles, the shortcomings of current empirical formulas of pile bearing capacity considering time effect are discussed. Based on the current research of the bearing capacity of static bearing piles in natural saturated clay, factors for the bearing capacity of long-term loaded old piles are analyzed. Then, based on analysis of the data from pile foundation bearing tests, the formula for calculating the ultimate bearing capacity of jacked piles considering the time effect and the current pile foundation technical code is proposed, in which the pile side resistance aging coefficient of pile side resistance is proposed, and some factors for the aging coefficient are discussed. Based on the experimental data, a method for calculating the parameters in the formula by using soil properties is proposed. The accuracy of the proposed method is verified by a field test. The results show that this pile side resistance aging coefficient can predict the bearing capacity of single pile under current code, increase the design value of the bearing capacity of old piles while ensuring safety. By using the undrained shear strength and plasticity index, the pile side resistance aging coefficient can be predicted.
Key words: old pile, ultimate bearing capacity, aging coefficient, undrained shear strength, field test
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