考虑时间效应的群桩负摩阻力模型试验研究
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摘要
基桩负摩阻力是桩基础设计中必须考虑的重要问题之一,但是针对考虑土体固结时间效应的群桩负摩阻力研究却相对较少。进行了在地面堆载固结条件下,黏性土层中3×3群桩负摩阻力性状的室内模型试验研究,测得了不同桩间距(3d,4d,6d)条件下各位置桩(角桩、边桩、中心桩)的桩侧负摩阻力、桩端阻力以及桩周土体分层沉降随固结时间的变化情况,分析了桩身下拽力和中性点位置随时间的变化规律;并进行了同等条件下单桩及2×2群桩(4d)试验作为比较分析。试验结果表明,群桩中桩侧负摩阻力引起的下拽力和中性点位置都存在明显的时间效应和群桩效应,其数值与基桩数、基桩的布置位置及桩间距等因素有关;在本文试验情况下,当桩–土相对位移达到2 mm时,桩侧负摩阻力将达到其最大值的80%～90%。
Negative skin friction is one of important problems in design of pile foundation,but the negative skin friction of pile groups considering time effect is less studied.The negative skin friction of 3 × 3 pile groups(3d,4d,6d) on the viscosous soil layer under surface load consolidation conditions is studied by model tests.The negative skin friction of pile side,tip resistance of pile and variation of settlement of each soil layer with consolidated time are measured.The position of neutral point and dragload are analyzed.For comparative analysis,a single pile and 2 × 2 pile groups(4d) are tested under the same conditions.The results show that the dragload and position of neutral point caused by the negative skin friction of pile side exhibit significant time effect and pile group effect for both the single pile and pile groups,and they are affected by the number of piles,the position of piles in group and the spacing of piles.It is also shown that the negative skin friction of pile side reaches 80%～ 90 % of the maximum one when the relative displacement of pile-soil reaches 2 mm under the present model test conditions.
Negative skin friction is one of important problems in design of pile foundation,but the negative skin friction of pile groups considering time effect is less studied.The negative skin friction of 3 × 3 pile groups(3d,4d,6d) on the viscosous soil layer under surface load consolidation conditions is studied by model tests.The negative skin friction of pile side,tip resistance of pile and variation of settlement of each soil layer with consolidated time are measured.The position of neutral point and dragload are analyzed.For comparative analysis,a single pile and 2 × 2 pile groups(4d) are tested under the same conditions.The results show that the dragload and position of neutral point caused by the negative skin friction of pile side exhibit significant time effect and pile group effect for both the single pile and pile groups,and they are affected by the number of piles,the position of piles in group and the spacing of piles.It is also shown that the negative skin friction of pile side reaches 80%～ 90 % of the maximum one when the relative displacement of pile-soil reaches 2 mm under the present model test conditions.
引文
[1]黄强.桩基工程若干热点技术问题[M].北京:中国建材工业出版社,1996.(HUANG Qiang.Some hotspot technical problems on pile foundation engineering[M].Beijing:China of Building Materials Industry Press,1996.(in Chinese))
[2]SAWAGUCHI M,TAKAHASHI K.Model test on negative friction acting on batter piles[C]//Proceedings of 32nd Japan Annual Meeting on Civil Engineering,1977:556–557.(in Japanese)
[3]SHIBATA T,SEKIGUCHI H,TSUJI I,YUKITOMO H.Model tests on negative friction acting on piles[C]//Proceedings of 22nd Japan Sympo SMFE,1977:49–55.(in Japanese)
[4]SHIBATA T,SEKIGUCHI H,YUKITOMO H.Model test and analysis of negative skin friction acting on piles[J].Soils and Foundations,1982,22(2):29–39.
[5]TOMA T M.A model study of negative skin friction on a fixed base pile in soft clay[D].Edinburgh:Heriot-watt University,1989.
[6]吴一伟,费涵昌,林侨兴,等.砂土液化对桩基的影响[J].同济大学学报,1995,23(3):360–364.(WU Yi-wei,FEI Han-chang,LIN Qiao-xing,et al.The effect of pile by sand clay liquefaction[J].Journal of Tongji University,1995,23(3):360–364.(in Chinese))
[7]张晓健.现浇混凝土薄壁管桩负摩阻力特性试验研究与分析[D].南京:河海大学,2006.(ZHANG Xiao-jian.Test study on properties of negative skin friction of thin-wall pipe pile using cast-in-situ concrete[D].Nanjing:Hohai University,2006.(in Chinese))
[8]谢依航.基桩负摩擦力之模型试验[D].台湾:国立中央大学,2006.(XIE Yi-hang.A model test for measuring downdrag behavior of a pile in a clay layer[D].Taiwan:National Central University,2006.(in Chinese))
[9]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,2007,29(6):824–830.(CHEN Ren-peng,ZHOU Wan-huang,CAO Wei-ping,et al.Improved hyperbolic model of load-transfer for pile-soil interface and its application in study of negative friction of single piles considering time effect[J].Chinese Journal of Geotechnical Engineering,2007,29(6):824–830.(in Chinese))
[10]夏力农.桩基负摩阻力特性的理论与试验研究[D].长沙:中南大学,2007.(XIA Li-nong.Theoretical and field test study on behavior of negative skin friction in piles[D].Changsha:Central South University,2007.(in Chinese))
[11]肖俊华,周国然,袁聚云,等.高桩码头桩基础负摩擦力现场试验研究——上海洋山深水港工程现场试验[J].岩土力学,2008,29(4):1097–1102.(XIAO Jun-hua,ZHOU Guo-ran,YUAN Ju-yun,et al.In-situ tests on negative skin friction of piles in high-piled wharf—In-situ test in Shanghai Yangshan deep water port engineering[J].Rock and Soil Mechanics,2008,29(4):1097–1102.(in Chinese))
[12]黄雪峰,陈正汉,哈双,等.大厚度自重湿陷性黄土中灌注桩承载性状与负摩阻力的试验研究[J].岩土工程学报,2007,29(3):338–346.(HUANG Xue-feng,CHEN Zheng-han,HA Shuang,et al.Research on bearing behaviors and negative friction force for filling piles in the site of collapsible loess with big thickness[J].Chinese Journal of Geotechnical Engineering,2007,29(3):338–346.(in Chinese))
[13]杨庆,孔纲强,郑鹏一,等.堆载条件下单桩负摩阻力模型试验研究[J].岩土力学,2008,29(10):2805–2810.(YANG Qing,KONG Gang-qiang,ZHENG Peng-yi,et al.Model test study on negative skin friction for single pile under surface load[J].Rock and Soil Mechanics,2008,29(10):2805–2810.(in Chinese))
[14]王兰民,孙军杰,黄雪峰,等.黄土场地地震陷时桩基负摩阻力的现场试验研究[J].岩土工程学报,2008,30(8):341–348.(WANG Lan-min,SUN Jun-jie,HUANG Xue-feng,et al.Field tests on negative skin friction along piles caused by seismic settlement of loess[J].Chinese Journal of Geotechnical Engineering,2008,30(8):341–348.(in Chinese))
[15]FELLENIUS B H.Basics of foundation design[M].2nd ed.Richmond:BiTeech Publishers,1999:164.
[16]JGJ94—2008建筑桩基技术规范[S].北京:中国建筑工业出版社,2008.(JGJ94—2008 Technical code for building pile foundations[S].Beijing:China Architecture and Building Press,2008.(in Chinese))
[2]SAWAGUCHI M,TAKAHASHI K.Model test on negative friction acting on batter piles[C]//Proceedings of 32nd Japan Annual Meeting on Civil Engineering,1977:556–557.(in Japanese)
[3]SHIBATA T,SEKIGUCHI H,TSUJI I,YUKITOMO H.Model tests on negative friction acting on piles[C]//Proceedings of 22nd Japan Sympo SMFE,1977:49–55.(in Japanese)
[4]SHIBATA T,SEKIGUCHI H,YUKITOMO H.Model test and analysis of negative skin friction acting on piles[J].Soils and Foundations,1982,22(2):29–39.
[5]TOMA T M.A model study of negative skin friction on a fixed base pile in soft clay[D].Edinburgh:Heriot-watt University,1989.
[6]吴一伟,费涵昌,林侨兴,等.砂土液化对桩基的影响[J].同济大学学报,1995,23(3):360–364.(WU Yi-wei,FEI Han-chang,LIN Qiao-xing,et al.The effect of pile by sand clay liquefaction[J].Journal of Tongji University,1995,23(3):360–364.(in Chinese))
[7]张晓健.现浇混凝土薄壁管桩负摩阻力特性试验研究与分析[D].南京:河海大学,2006.(ZHANG Xiao-jian.Test study on properties of negative skin friction of thin-wall pipe pile using cast-in-situ concrete[D].Nanjing:Hohai University,2006.(in Chinese))
[8]谢依航.基桩负摩擦力之模型试验[D].台湾:国立中央大学,2006.(XIE Yi-hang.A model test for measuring downdrag behavior of a pile in a clay layer[D].Taiwan:National Central University,2006.(in Chinese))
[9]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,2007,29(6):824–830.(CHEN Ren-peng,ZHOU Wan-huang,CAO Wei-ping,et al.Improved hyperbolic model of load-transfer for pile-soil interface and its application in study of negative friction of single piles considering time effect[J].Chinese Journal of Geotechnical Engineering,2007,29(6):824–830.(in Chinese))
[10]夏力农.桩基负摩阻力特性的理论与试验研究[D].长沙:中南大学,2007.(XIA Li-nong.Theoretical and field test study on behavior of negative skin friction in piles[D].Changsha:Central South University,2007.(in Chinese))
[11]肖俊华,周国然,袁聚云,等.高桩码头桩基础负摩擦力现场试验研究——上海洋山深水港工程现场试验[J].岩土力学,2008,29(4):1097–1102.(XIAO Jun-hua,ZHOU Guo-ran,YUAN Ju-yun,et al.In-situ tests on negative skin friction of piles in high-piled wharf—In-situ test in Shanghai Yangshan deep water port engineering[J].Rock and Soil Mechanics,2008,29(4):1097–1102.(in Chinese))
[12]黄雪峰,陈正汉,哈双,等.大厚度自重湿陷性黄土中灌注桩承载性状与负摩阻力的试验研究[J].岩土工程学报,2007,29(3):338–346.(HUANG Xue-feng,CHEN Zheng-han,HA Shuang,et al.Research on bearing behaviors and negative friction force for filling piles in the site of collapsible loess with big thickness[J].Chinese Journal of Geotechnical Engineering,2007,29(3):338–346.(in Chinese))
[13]杨庆,孔纲强,郑鹏一,等.堆载条件下单桩负摩阻力模型试验研究[J].岩土力学,2008,29(10):2805–2810.(YANG Qing,KONG Gang-qiang,ZHENG Peng-yi,et al.Model test study on negative skin friction for single pile under surface load[J].Rock and Soil Mechanics,2008,29(10):2805–2810.(in Chinese))
[14]王兰民,孙军杰,黄雪峰,等.黄土场地地震陷时桩基负摩阻力的现场试验研究[J].岩土工程学报,2008,30(8):341–348.(WANG Lan-min,SUN Jun-jie,HUANG Xue-feng,et al.Field tests on negative skin friction along piles caused by seismic settlement of loess[J].Chinese Journal of Geotechnical Engineering,2008,30(8):341–348.(in Chinese))
[15]FELLENIUS B H.Basics of foundation design[M].2nd ed.Richmond:BiTeech Publishers,1999:164.
[16]JGJ94—2008建筑桩基技术规范[S].北京:中国建筑工业出版社,2008.(JGJ94—2008 Technical code for building pile foundations[S].Beijing:China Architecture and Building Press,2008.(in Chinese))
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