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| Monitoring negative skin frictions on PHC pipe piles using FBG sensors |
| YANG Yong1,2,DAI Zihang1 |
(1. School of Civil Engineering,Fuzhou University,Fuzhou,Fujian 350116,China;2. Engineering Department,Fujian Mingwei Food Co.,Ltd.,Fuqing,Fujian 350301,China)
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Abstract At present,there are almost no reports on the field measurement of the prestressed high-strength concrete(PHC) pipe pile subjected to negative skin friction. To reveal the characteristics of negative skin friction on PHC pile piles,the measures of installation of and protection to the fiber Bragg grating sensors(FBG) on the PHC pipe piles were studied and the strains of 4 piles of a building foundation subjected to negative skin frictions induced by the recent soil filling were monitored for 21 months. The axial forces of the piles were deduced and their variation curves were plotted. The distribution and variation features of the axial forces of the piles under the loads from the superstructure and the negative skin frictions were analyzed. The measured values of the drag loads induced by the negative skin frictions on the PHC piles were notably greater than the values calculated according to the current Chinese code-Technical Code for Building Pile Foundation(JGJ94-2008),indicating that the current theoretical method still needs to be improved. In the strata with non-uniformly distributed soft and stiff layers,the negative skin and positive skin frictions might occur alternately and how to consider this kind of circumstance in theoretical calculations is worth studying. The quality of and avoiding the construction damage to the asphalt coating are the key to ensure the effective reduction of the negative skin friction.
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[1] 赵明华,贺 炜,曹文贵. 基桩负摩阻力计算方法初探[J]. 岩土力学,2004,25(9):1 442–1 446.(ZHAO Minghua,HE Wei,CAO Wengui. Study on calculation of negative skin friction resistance on piles[J]. Rock and Soil Mechanics,2004,25(9):1 442–1 446.(in Chinese))
[2] 赵明华,刘思思. 多层地基单桩负摩阻力的数值模拟计算[J]. 岩土工程学报,2008,30(3):336–340.(ZHAO Minghua,LIU Sisi. Numerical simulation of negative skin friction on single pile in multiple layer deposits[J]. Chinese Journal of Geotechnical Engineering,2008,30(3):336–340.(in Chinese))
[3] 孔纲强,杨 庆,郑鹏一,等. 考虑时间效应的斜桩基负摩阻力室内模型试验研究[J]. 岩土工程学报,2009,31(4):617–621.(KONG Gangqiang,YANG Qing,ZHENG Pengyi,et al. Model tests on negative skin friction for inclined pile considering time effect[J]. Chinese Journal of Geotechnical Engineering,2009,31(4):617–621.(in Chinese))
[4] 律文田,冷伍明,王永和. 软土地区桥台桩基负摩阻力试验研究[J]. 岩土工程学报,2005,27(6):642–645.(LU Wentian,LENG Wuming,WANG Yonghe. In-situ tests on negative friction resistance of abutment piles in soft soil[J]. Chinese Journal of Geotechnical Engineering,2005,27(6):642–645.(in Chinese))
[5] 吕颖钊. 钻孔灌注桩承载性能长期监测技术要求[J]. 浙江交通职业技术学院学报,2016,17(1):17–21.(LU Yingzhao. Technical requirements for long term monitoring of bearing performance of bored pile[J]. Journal of Zhejiang Institute of Communications,2016,17(1):17–21.(in Chinese))
[6] 徐青华,郭圣栋,张 璟. 苏通大桥主塔超大型群桩基础监测[J]. 公路交通科技,2007,(11):118–121.(XU Qinhua,GUO Shengdong,ZHANG Jing. Monitoring of super large pile group foundation of main tower of Su Tong Bridge[J]. Journal of Highway and Transportation Research and Development,2007,(11):118–121.(in Chinese))
[7] 秦邦民,李筱艳. 基桩安全监测及多传感器布置优化[J]. 西部探矿工程,2010,(7):20–22.(QIN Bangmin,LI Xiaoyan. Pile safety monitoring and sensor layout optimization[J]. West-China Exploration Engineering,2010,(7):20–22.(in Chinese))
[8] 恽斌峰. 布拉格光纤光栅传感器理论与实验研究[博士学位论文][D]. 南京:东南大学,2006.(YUN Binfeng. Theoretical and experimental study of fiber Bragg grating sensors[Ph. D. Thesis][D]. Nanjing:Southeast University,2006.(in Chinese))
[9] 肖俊华,袁聚云,赵锡宏. 桩基负摩擦力的试验模拟和计算应用[M]. 北京:科学出版社,2009:53–70.(XIAO Junhua,YUAN Jüyun,ZHAO Xihong. Experimental simulation and calculation of negative friction of pile foundation[M]. Beijing:Science Press,2009:53–70. (in Chinese))
[10] 张 茜,孙学先. 厚层黄土地区钻孔灌注长桩的负摩阻力[J]. 土工基础,2007,21(6):50–52.(ZHANG Qian,SUN Xuexian. The discussion about negative friction at long bored pile in deep loess[J]. Soil Engineering and Foundation,2007,21(6):50–52.(in Chinese))
[11] 高大钊,赵春风,徐 斌. 桩基础的设计方法与施工技术[M]. 北京:机械工业出版社,1999:84–85.(GAO Dazhao,ZHAO Chunfeng,XU Bing. The pile foundation design methods and construction technology[M]. Beijing:China Machine Press,1999:84–85.(in Chinese))
[12] 中华人民共和国行业标准编写组. JGJ94—2008 建筑桩基技术规范[S]. 北京:中国建筑工业出版社,2008.(The Professional Standards Compilation Group of People?s Republic of China. JGJ94—2008 Theoretical code for building pile foundations[S]. Beijing:China Architecture and Building Press,2008.(in Chinese))
[13] TAKAHASHI K,KATAYAMA T,SOUND S. Positive and negative skin friction on a pile in soft clayed ground at Haneda[C]// GEO-COAST?91.3-6. Yokohama:[s.n.],1991:6–13.
[14] 夏力农. 桩基负摩阻力特性的理论与试验研究[博士学位论文][D]. 长沙:中南大学,2007.(XIA Linong. Theoretical and field test study on behavior of negative skin friction in piles[Ph. D. Thesis][D]. Changsha:Central South University,2007.(in Chinese))
[15] 夏力农,王星华,蒋春平. 桩顶荷载对桩基负摩阻力特性的影响[J]. 防灾减灾工程学报,2005,25(4):359–362.(XIA Linong,WANG Xinghua,JIANG Chunping. Effect of pile top load on negative friction characteristics of pile foundation[J]. Journal of Disaster Prevention and Mitigation Engineering,2005,25(4):359–362.(in Chinese))
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