盾构掘进引起的邻近桩基水平附加荷载分析
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摘要
基于Mindlin基本解及弹性力学基本理论,考虑刀盘挤土效应产生的附加推力、土体地层软化特性且不均匀分布的盾壳摩阻力及土体损失等因素推导得到盾构掘进过程中邻近桩基的水平附加荷载解析解答。算例分析结果表明:在x方向上,盾构刀盘到达前,邻近桩基承受附加压力荷载;刀盘通过桩基平面后,附加荷载转为拉力;在盾尾通过后,桩身附加拉力荷载达到最大。在y方向上,土体损失是引起桩身的附加荷载的主要因素,特别是在盾尾通过桩基平面后,对应于隧道拱顶及拱底附近位置桩身分别承受较大的附加压力及附加拉力荷载,这将会导致桩基产生较大的挠曲变形、弯矩及剪力,为最不利施工工况。
The analytical solutions of the lateral additional loads on adjacent pile induced by shield advancing process were derived on the basis of Mindlin's solutions and the basic theory of elasticity. The proposed analytical solutions take full accounts of the additional thrust induced by compacting effects of the bulkhead, non-uniform distributed shield shell friction forces with softening property in soft soil ground and soil loss caused by shield over-excavation. The proposed solutions were verified by sample analysis. The analyzed results indicate that on the x-direction, the adjacent pile suffers additional pressure when the shield is approaching. During the passing of the bulkhead of the shield, the additional squeeze pressure transforms into additional tension pressure. Its values reach the maximum as the shield tail just leaves the pile. On the other hand, the soil loss is the main reason to generate the additional loads on the pile on y-direction. In particular, the depths of pile shaft that corresponds to the tunnel crown and invert lines level support lager magnitude of additional squeeze pressure and tension loads, respectively, which lead to excessive deflection, bending moments and shears on the pile shaft. Therefore, it is the most adverse condition for shield advancing an adjacent pile foundation.
The analytical solutions of the lateral additional loads on adjacent pile induced by shield advancing process were derived on the basis of Mindlin's solutions and the basic theory of elasticity. The proposed analytical solutions take full accounts of the additional thrust induced by compacting effects of the bulkhead, non-uniform distributed shield shell friction forces with softening property in soft soil ground and soil loss caused by shield over-excavation. The proposed solutions were verified by sample analysis. The analyzed results indicate that on the x-direction, the adjacent pile suffers additional pressure when the shield is approaching. During the passing of the bulkhead of the shield, the additional squeeze pressure transforms into additional tension pressure. Its values reach the maximum as the shield tail just leaves the pile. On the other hand, the soil loss is the main reason to generate the additional loads on the pile on y-direction. In particular, the depths of pile shaft that corresponds to the tunnel crown and invert lines level support lager magnitude of additional squeeze pressure and tension loads, respectively, which lead to excessive deflection, bending moments and shears on the pile shaft. Therefore, it is the most adverse condition for shield advancing an adjacent pile foundation.
引文
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[2]HUANG M,ZHANG C,LI Z.A simplified analysis method for the influence of tunneling on grouped piles[J].Tunnelling and Underground Space Technology,2009,24(4):410-422.
[3]黄茂松,张陈蓉,李早.开挖条件下非均质地基中被动群桩水平反应分析[J].岩土工程学报,2008,30(7):1017-1023.HUANG Maosong,ZHANG Chenrong,LI Zao.Lateral response of passive pile groups due to excavation-induced soil movement in stratified soils[J].Chinese Journal of Geotechnical Engineering,2008,30(7):1017-1023.
[4]章荣军,郑俊杰,蒲诃夫,等.基于p-y曲线分析隧道开挖对邻近单桩的影响[J].岩土工程学报,2010,32(12):1837-1845.ZHANG Rongjun,ZHENG Junjie,PU Hefu,et al.Response of adjacent single pile due to tunneling based on p-y curve[J].Chinese Journal of Geotechnical Engineering,2010,32(12):1837-1845.
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[8]魏纲,魏新江,丁智,等.顶管推进对邻近桩基的影响分析[J].岩土力学,2006,27(S):849-854.WEI Gang,WEI Xinjiang,DING Zhi,et al.Analysis of influence of pipe jacking construction on adjacent piles[J].Rock and Soil Mechanics,2006,27(S):849-854.
[9]LEE C J,CHIANG K H.Responses of single piles to tunneling-induced soil movements in sandy ground[J].Canadian Geotechnical Journal,2007,44(10):1224-1241.
[10]NG C W W,LU H,PENG S Y.Three-dimensional centrifuge modelling of the effects of twin tunneling on an existing pile[J].Tunnelling and Underground Space Technology,2013,35(4):189-199.
[11]NG C W,LU H.Effects of the construction sequence of twin tunnels at different depths on an existing pile[J].Canadian Geotechnical Journal,2014,51(2):173-183.
[12]魏新江,洪杰,魏纲.双圆盾构施工引起邻近桩基附加荷载的分析[J].岩土力学,2013,34(3):783-790.WEI Xinjiang,HONG Jie,WEI Gang.Analysis of additional load on adjacent pile foundation induced by double-O-tube shield tunnel construction[J].Rock and Soil Mechanics,2013,34(3):783-790.
[13]魏纲,徐日庆.软土隧道盾构法施工引起的纵向地面变形预测[J].岩土工程学报,2005,27(9):1077-1081.WEI Gang,XU Riqing.Prediction of longitudinal ground deformation due to tunnel construction with shield in soft soil[J].Chinese Journal of Geotechnical Engineering,2005,27(9):1077-1081.
[14]唐晓武,朱季,刘维,等.盾构施工过程中的土体变形研究[J].岩石力学与工程学报,2010,29(2):417-422.TANG Xiaowu,ZHU Ji,LIU Wei,et al.Research on soil deformation during shield construction process[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(2):417-422.
[15]林存刚,张忠苗,吴世明,等,软土地层盾构隧道施工引起的地面隆陷研究[J].岩石力学与工程学报,2011,30(12):2583-2590.LIN Cungang,ZHANG Zhongmiao,WU Shiming,et al.Study of ground heave and subsidence induced by shield tunnelling in soft ground[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(12):2583-2590.
[16]ALONSO E E,JOSA A,LEDESMA A.Negative skin friction on piles:a simplified analysis and prediction procedure[J].Geotechnique,1984,34(3):341-357.
[17]POTYONDY J G.Skin friction between various soils and construction materials[J].Geotechnique,1961,11(4):339-353.
[18]张乾青,李术才,李利平,等.考虑侧阻软化和端阻硬化的群桩沉降简化算法[J].岩石力学与工程学报,2013,32(3):615-624.ZHANG Qianqing,LI Shucai,LI Liping.Simplified method for settlement prediction of pile groups considering skin friction softening and end resistance hardening[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(3):615-624.
[19]梁荣柱,夏唐代,林存刚,等.软土地区盾构施工引起地表及深层土体水平位移研究[J].岩石力学与与工程学报,2015,34(3):583-593.LIANG Rongzhu,XIA Tangdai,LIN Cungang,et al.Analysis on ground surface displacement and horizontal movement of deep soils induced by shield advancing[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(3):583-593.
[20]王洪新.土压平衡盾构刀盘挤土效应及刀盘开口率对盾构正面接触压力影响[J].土木工程学报,2009,42(7):113-118.WANG Hongxin.Effect of cutterhead compressing the front soil and influence of head aperture ratio on contact pressure of EPB shield to the front soil[J].China Civil Engineering Journal,2009,42(7):113-118.
[21]魏纲,黄志义,徐日庆,等.土压平衡盾构施工引起挤土效应研究[J].岩石力学与工程学报,2005,24(19):3522-3528.WEI Gang,HUANG Zhiyi,XU Riqing,et al.Study on soilcompacting effects induced by earth pressure balance shield construction[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(19):3522-3528.
[22]侯永茂,杨国祥,葛修润,等.超大直径土压土压平衡盾构土舱压力和开挖面水土压力分布特性研究[J].岩土力学,2012,33(9):2713-2718.HOU Yongmao,YANG Guoxiang,GE Xiurun,et al.study of distrubiton properties of water and earth pressure at excavation face and in chamber of earth pressure balance shield with super-large diameter[J].Rock and Soil Mechanics,2012,33(9):2713-2718.
[23]杨敏,赵锡宏.分层土中的单桩分析[J].同济大学学报(自然科学版),1992,20(4):421-428.YANG Min,ZHAO Xihong.An approach for a single pile in layered soil[J].Journal of Tongji University(Natural Science),1992,20(4):421-428.
[24]SAGASETA C.Analysis of undrained soil deformation due to ground loss[J].Geotechnique,1987,37(3):301-320.
[25]PINTO F,WHITTLE A J.Ground movements due to shallow tunnels in soft ground.I:analytical solutions[J].Journal of Geotechnical and Geoenvironmental Engineering,2013,140(4):04013040-1-17.
[26]TIMOSHENKO P,GOODIER J N.Theory of elasticity[M].New York:Mc Graw Hill,1970:5-90.
[27]CHENG C Y,DASARI G R,CHOW Y K,et al.Finite element analysis of tunnel-soil-pile interaction using displacement controlled model[J].Tunnelling and Underground Space Technology,2007,22(4):450-466.
[2]HUANG M,ZHANG C,LI Z.A simplified analysis method for the influence of tunneling on grouped piles[J].Tunnelling and Underground Space Technology,2009,24(4):410-422.
[3]黄茂松,张陈蓉,李早.开挖条件下非均质地基中被动群桩水平反应分析[J].岩土工程学报,2008,30(7):1017-1023.HUANG Maosong,ZHANG Chenrong,LI Zao.Lateral response of passive pile groups due to excavation-induced soil movement in stratified soils[J].Chinese Journal of Geotechnical Engineering,2008,30(7):1017-1023.
[4]章荣军,郑俊杰,蒲诃夫,等.基于p-y曲线分析隧道开挖对邻近单桩的影响[J].岩土工程学报,2010,32(12):1837-1845.ZHANG Rongjun,ZHENG Junjie,PU Hefu,et al.Response of adjacent single pile due to tunneling based on p-y curve[J].Chinese Journal of Geotechnical Engineering,2010,32(12):1837-1845.
[5]ZHANG R J,ZHENG J J,ZHANG L M,et al.An analysis method for the influence of tunneling on adjacent loaded pile groups with rigid elevated caps[J].International Journal for Numerical and Analytical Methods in Geomechanics,2011,35(18):1949-1971.
[6]孙庆,杨敏,汪浩,等.基于p-y曲线法分析隧道开挖条件下邻近桩基的水平反应[J].岩土工程学报,2012,34(11):2100-2107.SUN Qing,YANG Min,WANG Hao et al.Tunnelling-induced lateral response of adjacent piles based on p-y curve[J].Chinese Journal of Geotechnical Engineering,2012,34(11):2100-2107.
[7]李永盛,黄海鹰.盾构推进对相邻桩体力学影响的实用计算方法[J].同济大学学报(自然科学版),1997,25(3):274-280.LI Yongsheng,HUANG Haiying.Computation of mechanical effects on adjacent piles by shield excavation[J].Journal of Tongji University(Natural Science),1997,25(3):274-280.
[8]魏纲,魏新江,丁智,等.顶管推进对邻近桩基的影响分析[J].岩土力学,2006,27(S):849-854.WEI Gang,WEI Xinjiang,DING Zhi,et al.Analysis of influence of pipe jacking construction on adjacent piles[J].Rock and Soil Mechanics,2006,27(S):849-854.
[9]LEE C J,CHIANG K H.Responses of single piles to tunneling-induced soil movements in sandy ground[J].Canadian Geotechnical Journal,2007,44(10):1224-1241.
[10]NG C W W,LU H,PENG S Y.Three-dimensional centrifuge modelling of the effects of twin tunneling on an existing pile[J].Tunnelling and Underground Space Technology,2013,35(4):189-199.
[11]NG C W,LU H.Effects of the construction sequence of twin tunnels at different depths on an existing pile[J].Canadian Geotechnical Journal,2014,51(2):173-183.
[12]魏新江,洪杰,魏纲.双圆盾构施工引起邻近桩基附加荷载的分析[J].岩土力学,2013,34(3):783-790.WEI Xinjiang,HONG Jie,WEI Gang.Analysis of additional load on adjacent pile foundation induced by double-O-tube shield tunnel construction[J].Rock and Soil Mechanics,2013,34(3):783-790.
[13]魏纲,徐日庆.软土隧道盾构法施工引起的纵向地面变形预测[J].岩土工程学报,2005,27(9):1077-1081.WEI Gang,XU Riqing.Prediction of longitudinal ground deformation due to tunnel construction with shield in soft soil[J].Chinese Journal of Geotechnical Engineering,2005,27(9):1077-1081.
[14]唐晓武,朱季,刘维,等.盾构施工过程中的土体变形研究[J].岩石力学与工程学报,2010,29(2):417-422.TANG Xiaowu,ZHU Ji,LIU Wei,et al.Research on soil deformation during shield construction process[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(2):417-422.
[15]林存刚,张忠苗,吴世明,等,软土地层盾构隧道施工引起的地面隆陷研究[J].岩石力学与工程学报,2011,30(12):2583-2590.LIN Cungang,ZHANG Zhongmiao,WU Shiming,et al.Study of ground heave and subsidence induced by shield tunnelling in soft ground[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(12):2583-2590.
[16]ALONSO E E,JOSA A,LEDESMA A.Negative skin friction on piles:a simplified analysis and prediction procedure[J].Geotechnique,1984,34(3):341-357.
[17]POTYONDY J G.Skin friction between various soils and construction materials[J].Geotechnique,1961,11(4):339-353.
[18]张乾青,李术才,李利平,等.考虑侧阻软化和端阻硬化的群桩沉降简化算法[J].岩石力学与工程学报,2013,32(3):615-624.ZHANG Qianqing,LI Shucai,LI Liping.Simplified method for settlement prediction of pile groups considering skin friction softening and end resistance hardening[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(3):615-624.
[19]梁荣柱,夏唐代,林存刚,等.软土地区盾构施工引起地表及深层土体水平位移研究[J].岩石力学与与工程学报,2015,34(3):583-593.LIANG Rongzhu,XIA Tangdai,LIN Cungang,et al.Analysis on ground surface displacement and horizontal movement of deep soils induced by shield advancing[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(3):583-593.
[20]王洪新.土压平衡盾构刀盘挤土效应及刀盘开口率对盾构正面接触压力影响[J].土木工程学报,2009,42(7):113-118.WANG Hongxin.Effect of cutterhead compressing the front soil and influence of head aperture ratio on contact pressure of EPB shield to the front soil[J].China Civil Engineering Journal,2009,42(7):113-118.
[21]魏纲,黄志义,徐日庆,等.土压平衡盾构施工引起挤土效应研究[J].岩石力学与工程学报,2005,24(19):3522-3528.WEI Gang,HUANG Zhiyi,XU Riqing,et al.Study on soilcompacting effects induced by earth pressure balance shield construction[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(19):3522-3528.
[22]侯永茂,杨国祥,葛修润,等.超大直径土压土压平衡盾构土舱压力和开挖面水土压力分布特性研究[J].岩土力学,2012,33(9):2713-2718.HOU Yongmao,YANG Guoxiang,GE Xiurun,et al.study of distrubiton properties of water and earth pressure at excavation face and in chamber of earth pressure balance shield with super-large diameter[J].Rock and Soil Mechanics,2012,33(9):2713-2718.
[23]杨敏,赵锡宏.分层土中的单桩分析[J].同济大学学报(自然科学版),1992,20(4):421-428.YANG Min,ZHAO Xihong.An approach for a single pile in layered soil[J].Journal of Tongji University(Natural Science),1992,20(4):421-428.
[24]SAGASETA C.Analysis of undrained soil deformation due to ground loss[J].Geotechnique,1987,37(3):301-320.
[25]PINTO F,WHITTLE A J.Ground movements due to shallow tunnels in soft ground.I:analytical solutions[J].Journal of Geotechnical and Geoenvironmental Engineering,2013,140(4):04013040-1-17.
[26]TIMOSHENKO P,GOODIER J N.Theory of elasticity[M].New York:Mc Graw Hill,1970:5-90.
[27]CHENG C Y,DASARI G R,CHOW Y K,et al.Finite element analysis of tunnel-soil-pile interaction using displacement controlled model[J].Tunnelling and Underground Space Technology,2007,22(4):450-466.