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IMPROVEMENT OF THE SIMPLE CONVERSION METHOD FOR LOAD-SETTLEMENT CURVES IN SELF-BALANCE TESTS
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摘要: 简单转换法是自平衡静载试验Q-s曲线转化为传统静载试验曲线的常用方法，上推桩桩身压缩量的计算精度决定了简单转换法及自平衡静载试验结果的准确性。针对现行简单转换法的不足，对上推桩桩身压缩量的计算方法展开研究，通过对上推桩受力机理的分析和有限元计算，得出桩侧摩阻力分布系数C直接影响上推桩桩身压缩量的计算精度，上推桩在上推力的作用下，桩侧负摩阻力沿桩身向上急剧减小，呈下凹双曲线型分布，且分布系数C随基桩长径比的增大而增大，由此给出了桩身压缩量更为精确的计算式，改进了现行的简单转换法。工程实践证明，改进的简单转换法更为准确、实用。Abstract: The simple conversion method is a common method for transform Q-s curves of self-balanced static load tests into curves of traditional static load tests. The calculation accuracy of compression for piles of being pushed-up determined the accuracy of the simple conversion method and the results of self-balanced static load tests.Aimed at the deficiency of the current simple conversion method, the compression calculations of the pushed-up piles were studied. Based on analysis of the force mechanisms for pushed-up piles and the finite element calculations, the distribution coefficient C of the side friction resistance for piles were obtained, which could influence the calculation accuracy of compression for pushed-up piles. Under the action of the thrust, the negative friction on the sides of piles decreased sharply upward along pile shafts, and the distribution of the negative friction was a concave hyperbola. With the increase of aspect ratios, the values of C increased.Therein, the calculation formula of pile compression was more accurate. Engineering examples showed that the improved simple transformation method was more accurate and practical.
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[1] OSTERBERG J. New Device for Load Testing Driven Piles and Drilled Shaft Separates Friction and End Bearing[J]. Piling and Deep Foundations, 1989, 5(2):421-427. [2] 中华人民共和国住房和城乡建设部.建筑基桩自平衡静载试验技术规程:JGJ/T 403-2017[S].北京:中国建筑工业出版社, 2017. [3] 中华人民共和国交通运输部.基桩自平衡法静载试验用荷载箱:JT/T 875-2013[S].北京:人民交通出版社, 2014. [4] 马远刚, 郑轩.自平衡试桩法荷载箱设计位置探讨[J]. 桥梁建设, 2006(增刊1):125-127. [5] 龚维明, 戴国亮, 蒋永生, 等.桩承载力自平衡测试理论与实践[J]. 建筑结构学报, 2002, 23(1):82-88. [6] 江苏省技术监督局.桩承载力自平衡测试技术规程:DB 32/T291-1999[S].南京:江苏省技术监督局, 1999. [7] 鲍育明, 刘亚文, 李志成, 等.自平衡法在桩基承载力检测中的应用[J]. 解放军理工大学学报(自然科学版), 2003, 4(3):49-52. [8] 龚维明, 蒋永生, 翟晋.桩承载力自平衡测试法[J]. 岩土工程学报, 2000, 22(5):532-536. [9] 中华人民共和国建设部.建筑桩基技术规范:JGJ 94-2008[S].北京:中国建筑工业出版社, 2008. [10] SEON H, MOGHADDAM R B, LAWSON W D. Assessment of Methods for Construction of an Equivalent Top Loading Curve from O-Cell Test Data[J]. Soils and Foundations, 2016, 56(5):889-903. [11] 马文杰, 蒋代军, 王博林, 等.桩长径比对桩基承载性能影响的试验研究[J]. 四川建筑科学研究, 2018, 44(6):69-73. [12] 曾友金, 章为民.桩长和桩轴向抗压刚度对桩极限承载力发挥的影响[J]. 土工基础, 2002, 3(9):50-53. [13] 鲁嘉, 喻军, 陈金祥, 等.砂土中成桩工艺对桩基承载性能影响的室内模型试验研究[J]. 岩石力学与工程学报, 2012, 31(5):1055-1063. [14] 陈仁朋, 周万欢, 曹卫平, 等.改进的桩土界面荷载传递双曲线模型及其在单桩负摩阻力时间效应研究中的应用[J]. 岩土工程学报, 2007(6):824-830. [15] 齐静静.湿陷性黄土地区地基处理试验研究[D].南京:东南大学, 2005. -
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