一种斜坡桥梁桩基础自由段桩长确定方法
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摘要
以斜坡桥梁桩基自由段桩长的确定方法为研究目标,将桩前自由段桩长范围内存在变形趋势的岩土体视为三维楔形受力体,考虑桩前受力体的自重及两侧拉力、受力体底部的极限抗滑力和摩阻力、桩土间接触压应力,推导其滑动力合力计算式,依据受力体的临界稳定状态确定斜坡桥梁桩基自由段桩长,并采用C#开发斜坡桥梁桩基自由段桩长的计算程序。运用该程序对斜坡桩基自由段桩长取值影响因素进行的敏感性分析结果表明:斜坡坡角、桩土接触压应力、内摩擦角对自由段桩长取值的影响较敏感,而桩周岩土体重度对自由段桩长取值的敏感性较小。采用此方法对长昆客运专线部分陡坡桥基自由段桩长设计取值的计算结果表明:当斜坡坡度较缓、地层较为坚硬时,位于其上的桥基内力计算可忽略自由段桩长的影响;当斜坡坡度较陡或斜坡岩土体强度较低时,计算得到的自由段桩长取值相对较大,斜坡桥梁桩基础设计须考虑自由段桩长对桩基内力计算的影响。
Taking the method for determining the free segment length of bridge pile foundation on slope as the research target,the rock and soil mass with deformation trend in the free segment length of front pile is regarded as the three-dimensional wedge-shaped force body.Considering the dead weight of the force body in front of pile,the pulling force on both sides,the ultimate sliding resistance,frictional resistance at the bottom of the force body and the contact compressive stress between pile and soil,the formula for calculating its resultant sliding force is deduced.Based on the critical stability of the force body,the free segment length of bridge pile foundation on slope is determined,and the calculation program for the free segment length of bridge pile foundation on slope is developed by C#.The sensitivity analysis of the influencing factors on the free segment length of pile foundation on slope is carried out by using this program.Results show that the slope angle,the pile-soil contact compressive stress and the internal friction angle are relatively sensitive to the free segment length of pile,while the volume-weight of the rock and soil mass surrounding the pile is less sensitive to the free segment length of pile.The proposed method is used to calculate the design values of some free segment lengths of the steep slope bridge foundation on Chang-Kun passenger dedicated line.Results show that when the slope is gentle and the stratum is hard,the influence of the free segment length of pile can be neglected in the calculation of the internal force on bridge foundation.When the slope is steep or the strength of slope rock and soil is low,the calculated value of the free segment length of pile is relatively large.The influence of the free segment length of pile on the calculation of the internal force of pile foundation should be considered in the design of bridge pile foundation on steep slope.
Taking the method for determining the free segment length of bridge pile foundation on slope as the research target,the rock and soil mass with deformation trend in the free segment length of front pile is regarded as the three-dimensional wedge-shaped force body.Considering the dead weight of the force body in front of pile,the pulling force on both sides,the ultimate sliding resistance,frictional resistance at the bottom of the force body and the contact compressive stress between pile and soil,the formula for calculating its resultant sliding force is deduced.Based on the critical stability of the force body,the free segment length of bridge pile foundation on slope is determined,and the calculation program for the free segment length of bridge pile foundation on slope is developed by C#.The sensitivity analysis of the influencing factors on the free segment length of pile foundation on slope is carried out by using this program.Results show that the slope angle,the pile-soil contact compressive stress and the internal friction angle are relatively sensitive to the free segment length of pile,while the volume-weight of the rock and soil mass surrounding the pile is less sensitive to the free segment length of pile.The proposed method is used to calculate the design values of some free segment lengths of the steep slope bridge foundation on Chang-Kun passenger dedicated line.Results show that when the slope is gentle and the stratum is hard,the influence of the free segment length of pile can be neglected in the calculation of the internal force on bridge foundation.When the slope is steep or the strength of slope rock and soil is low,the calculated value of the free segment length of pile is relatively large.The influence of the free segment length of pile on the calculation of the internal force of pile foundation should be considered in the design of bridge pile foundation on steep slope.
引文
[1]高宗余,方秦汉,卫军.中国铁路桥梁技术发展与展望[J].铁道工程学报,2007(1):55-59.(GAO Zongyu,FANG Qinhan,WEI Jun.Development and Prospects for Technology of Railway Bridge in China[J].Journal of Railway Engineering Society,2007(1):55-59.in Chinese)
[2]铁道第三侦察设计院.TB 10002.5—2005铁路桥涵地基和基础设计规范[S].北京:中国铁道出版社,2005.
[3]王春雷,谢强.桥基荷载作用下三维高边坡岩体力学行为及桥基位置确定的研究[J].中国铁道科学,2011,32(2):136-138.(WANG Chunlei,XIE Qiang.Study on the Three-Dimensional Mechanical Behaviour of the Rock Mass on High Slope under Bridge Foundation Load and the Determination of Bridge Foundation Position[J].China Railway Science,2011,32(2):136-138.in Chinese)
[4]铁道部第一勘测设计院.铁路工程地质手册[M].北京:中国铁道出版社,1999.
[5]徐健强.黄土陡坡桥梁桩基础设计[J].铁道标准设计,2011(9):40-47.(XU Jianqiang.Design of Bridge Pile Foundation on Steep Loess Slopes[J].Railway Standard Design,2011(9):40-47.in Chinese)
[6]BROMS B B.Lateral Resistance of Piles in Cohesive Soils[J].Journal of Soil Mechanics and Foundation Engineering,1964,90(2):122-155.
[7]BROWN D A,MORR I C.Lateral Load Behavior of Pile Group in Sand[J].Journal of Geotechnical Engineering,ASCE,1988,114(11):1261-1276.
[8]ASHOUR M,NORRIS P.Modeling Lateral Soil-Pile Response Based on Soil-Pile Interaction[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(5):420-428.
[9]蔺鹏臻,武发辉,杨子江.考虑边坡效应的桥梁桩基受力分析[J].中国铁道科学,2016,37(4):54-60.(LIN Pengzhen,WU Fahui,YANG Zijiang.Mechanics Analysis of Bridge Pile Foundation Considering Slope Effect[J].China Railway Science,2016,37(4):54-60.in Chinese)
[10]重庆市建设委员会,重庆市国土资源和房屋管理局.DB 50/5029—2004地质灾害防治工程设计规范[S].重庆:重庆市国土资源和房屋管理局,2004.
[11]周春梅,殷坤龙,简文星.滑动面倾斜时抗滑桩弹塑性区临界高度的计算[J].岩土力学,2008,29(7):1945-1954.(ZHOU Chunmei,YIN Kunlong,JIAN Wenxing.Calculation of Critical Height of Rock-Soil Elastoplastic Area before Anti-Slide Pile on Declining Sliding Surface[J].Rock and Soil Mechanics,2008,29(7):1945-1954.in Chinese)
[12]张永杰,李侑军,赵明华,等.高陡斜坡作用下群桩基础设计计算方法[J].中国公路学报,2014,27(10):84-92.(ZHANG Yongjie,LI Youjun,ZHAO Minghua,et al.Design and Calculation Method for Pile Group Foundation in High and Steep Slope[J].China Journal of Highway and Transport,2014,27(10):84-92.in Chinese)
[13]蒋爵光,谢强,吴光.北盘江大桥岸坡稳定性及桥基选址的综合分析[J].铁道工程学报,1995(3):75-81.(JIANG Jueguang,XIE Qiang,WU Guang.Synthesis Analysis on Stability of River's Bank Slopes and Disposition of Bridge Foundations for Beipanjiang Railway Bridge[J].Journal of Railway Engineering Society,1995(3):75-81.in Chinese)
[14]赵文,谢强,龙德育.高陡岸坡桥基合理位置确定方法[J].中国铁道科学,2004,25(6):94-98.(ZHAO Wen,XIE Qiang,LONG Deyu.Method for Reasonably Positioning Bridge Foundation on High-Steep Slope[J].China Railway Science,2004,25(6):94-98.in Chinese)
[2]铁道第三侦察设计院.TB 10002.5—2005铁路桥涵地基和基础设计规范[S].北京:中国铁道出版社,2005.
[3]王春雷,谢强.桥基荷载作用下三维高边坡岩体力学行为及桥基位置确定的研究[J].中国铁道科学,2011,32(2):136-138.(WANG Chunlei,XIE Qiang.Study on the Three-Dimensional Mechanical Behaviour of the Rock Mass on High Slope under Bridge Foundation Load and the Determination of Bridge Foundation Position[J].China Railway Science,2011,32(2):136-138.in Chinese)
[4]铁道部第一勘测设计院.铁路工程地质手册[M].北京:中国铁道出版社,1999.
[5]徐健强.黄土陡坡桥梁桩基础设计[J].铁道标准设计,2011(9):40-47.(XU Jianqiang.Design of Bridge Pile Foundation on Steep Loess Slopes[J].Railway Standard Design,2011(9):40-47.in Chinese)
[6]BROMS B B.Lateral Resistance of Piles in Cohesive Soils[J].Journal of Soil Mechanics and Foundation Engineering,1964,90(2):122-155.
[7]BROWN D A,MORR I C.Lateral Load Behavior of Pile Group in Sand[J].Journal of Geotechnical Engineering,ASCE,1988,114(11):1261-1276.
[8]ASHOUR M,NORRIS P.Modeling Lateral Soil-Pile Response Based on Soil-Pile Interaction[J].Journal of Geotechnical and Geoenvironmental Engineering,2000,126(5):420-428.
[9]蔺鹏臻,武发辉,杨子江.考虑边坡效应的桥梁桩基受力分析[J].中国铁道科学,2016,37(4):54-60.(LIN Pengzhen,WU Fahui,YANG Zijiang.Mechanics Analysis of Bridge Pile Foundation Considering Slope Effect[J].China Railway Science,2016,37(4):54-60.in Chinese)
[10]重庆市建设委员会,重庆市国土资源和房屋管理局.DB 50/5029—2004地质灾害防治工程设计规范[S].重庆:重庆市国土资源和房屋管理局,2004.
[11]周春梅,殷坤龙,简文星.滑动面倾斜时抗滑桩弹塑性区临界高度的计算[J].岩土力学,2008,29(7):1945-1954.(ZHOU Chunmei,YIN Kunlong,JIAN Wenxing.Calculation of Critical Height of Rock-Soil Elastoplastic Area before Anti-Slide Pile on Declining Sliding Surface[J].Rock and Soil Mechanics,2008,29(7):1945-1954.in Chinese)
[12]张永杰,李侑军,赵明华,等.高陡斜坡作用下群桩基础设计计算方法[J].中国公路学报,2014,27(10):84-92.(ZHANG Yongjie,LI Youjun,ZHAO Minghua,et al.Design and Calculation Method for Pile Group Foundation in High and Steep Slope[J].China Journal of Highway and Transport,2014,27(10):84-92.in Chinese)
[13]蒋爵光,谢强,吴光.北盘江大桥岸坡稳定性及桥基选址的综合分析[J].铁道工程学报,1995(3):75-81.(JIANG Jueguang,XIE Qiang,WU Guang.Synthesis Analysis on Stability of River's Bank Slopes and Disposition of Bridge Foundations for Beipanjiang Railway Bridge[J].Journal of Railway Engineering Society,1995(3):75-81.in Chinese)
[14]赵文,谢强,龙德育.高陡岸坡桥基合理位置确定方法[J].中国铁道科学,2004,25(6):94-98.(ZHAO Wen,XIE Qiang,LONG Deyu.Method for Reasonably Positioning Bridge Foundation on High-Steep Slope[J].China Railway Science,2004,25(6):94-98.in Chinese)