基坑开挖引起复合地基下方既有双线地铁隧道位移的计算方法
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摘要
为快速分析基坑开挖时复合地基及"双洞效应"对下方既有双线地铁隧道竖、横向位移的影响,首先,基于Mindlin位移解和Winkler地基模型,推导出复合地基中桩的侧摩阻力作用下单线隧道的竖、横向附加荷载,从而计算得到单线隧道竖、横向位移。然后,采用迭代法计算得到的"双洞效应"引起的隧道竖、横向位移叠加得到双线隧道总竖、横向位移,并与前人理论计算结果、监测数据对比验证。最后,分析桩参数、隧道位置改变对桩侧摩阻力和"双洞效应"引起隧道竖、横向位移的影响。研究结果表明:1)与前人理论计算结果相比,本文理论计算结果与实测数据更吻合,且提高原有2阶段分析方法运算效率28%以上;2)桩侧摩阻力和"双洞效应"对隧道竖、横向位移的影响是不可忽略的;3)仅考虑上方基坑开挖对既有双线隧道位移的影响时,在施工条件和规范允许情况下,应尽量减少预先设计的两隧道之间距离,并合理选取复合地基中桩的长度;4)迭代法比一次性法更加合理、精确,特别是计算横向"双洞效应"引起隧道横向位移时,应尽量采用迭代法计算。
In order to rapidly analyze the influence of composite foundation and " double-tube effect" on the vertical and lateral displacements of existing double-tube metro tunnel during foundation pit excavation, the vertical and lateral additional loads of single-tube tunnel under lateral resistance of pile in composite foundation is deduced to calculate the vertical and lateral displacements of single-tube tunnel based on Mindlin′s solution of displacement and Winkler foundation model. The total vertical and lateral displacements of double-tube tunnels can be obtained by superposition of tunnel vertical and lateral displacements caused by " double-tube effect" calculated by iterative method, which is verified by comparison with the previous theoretical calculation results and monitoring data. Finally, the influence of the pile parameters and tunnel positions on tunnel vertical and lateral displacements caused by pile lateral resistance or " double-tube effect" is analyzed. The results show that:(1) Compared with the previous theoretical calculation results, the theoretical calculation results in this paper are more consistent with the monitored data, and the calculation efficiency is more than 28% higher than that of the original two-stage analysis method.(2) The influence of pile lateral resistance and " double-tube effect" on tunnel vertical and lateral displacements are not negligible.(3) Considering only the influence of foundation pit excavation on the displacement of existing double-tube tunnel, the distance between two pre-designed tunnels should be reduced as far as possible, and the length of pile in composite foundation should be reasonably selected when construction conditions and rules permit.(4) The iterative method is more reasonable and accurate than one-time method, especially when calculating tunnel lateral displacement caused by lateral " double-tube effects".
In order to rapidly analyze the influence of composite foundation and " double-tube effect" on the vertical and lateral displacements of existing double-tube metro tunnel during foundation pit excavation, the vertical and lateral additional loads of single-tube tunnel under lateral resistance of pile in composite foundation is deduced to calculate the vertical and lateral displacements of single-tube tunnel based on Mindlin′s solution of displacement and Winkler foundation model. The total vertical and lateral displacements of double-tube tunnels can be obtained by superposition of tunnel vertical and lateral displacements caused by " double-tube effect" calculated by iterative method, which is verified by comparison with the previous theoretical calculation results and monitoring data. Finally, the influence of the pile parameters and tunnel positions on tunnel vertical and lateral displacements caused by pile lateral resistance or " double-tube effect" is analyzed. The results show that:(1) Compared with the previous theoretical calculation results, the theoretical calculation results in this paper are more consistent with the monitored data, and the calculation efficiency is more than 28% higher than that of the original two-stage analysis method.(2) The influence of pile lateral resistance and " double-tube effect" on tunnel vertical and lateral displacements are not negligible.(3) Considering only the influence of foundation pit excavation on the displacement of existing double-tube tunnel, the distance between two pre-designed tunnels should be reduced as far as possible, and the length of pile in composite foundation should be reasonably selected when construction conditions and rules permit.(4) The iterative method is more reasonable and accurate than one-time method, especially when calculating tunnel lateral displacement caused by lateral " double-tube effects".
引文
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[14]建筑桩基技术规范:JGJ 94-2008[S].北京:中国建筑工业出版社,2008.Technical code for building pile foundations:JGJ 94-2008[S].Beijing:China Architecture&Building Press,2008.
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[16]徐凌.软土盾构隧道纵向沉降研究[D].上海:同济大学,2005.XU Ling.Study of longitudinal settlement of shield tunnel in soft soil[D].Shanghai:Tongji University,2005.
[17]胡琦,凌道盛,陈云敏.基于Melan解的水平基床系数分析方法及工程运用[J].岩土力学,2009,30(1):34.HU Qi,LING Daosheng,CHEN Yunmin.Analytical method and engineering application of horizontal coefficients of subgrade reaction based on Melan′s solution[J].Rock and Soil Mechanics,2009,30(1):34.
[2]黄宏伟,黄栩,HELMUT S F.基坑开挖对下卧运营盾构隧道影响的数值模拟研究[J].土木工程学报,2012,45(3):182.HUANG Hongwei,HUANG Xu,HELMUT S F.Numerical analysis of the influence of deep excavation on underneath existing road tunnel[J].China Civil Engineering Journal,2012,45(3):182.
[3]王定军,王尉行,刘俊景,等.基坑开挖对下卧隧道变形影响分析及合理加固范围研究[J].城市轨道交通研究,2018,21(4):43.WANG Dingjun,WANG Weixing,LIU Junjing,et al.Influence of foundation pit excavation on the deformation of underlying tunnel and the reasonable reinforcement range[J].Urban Mass Transit,2018,21(4):43.
[4]赵俊,甘鹏路,申文明,等.复合地层中基坑开挖对下卧隧道变形影响研究[J].隧道建设,2014,34(2):118.ZHAO Jun,GAN Penglu,SHEN Wenming,et al.Study of influence of excavation of foundation pit on deformation of underlying tunnel in complex ground[J].Tunnel Construction,2014,34(2):118.
[5]张治国,张孟喜,王卫东.基坑开挖对临近地铁隧道影响的两阶段分析方法[J].岩土力学,2011,32(7):2085.ZHANG Zhiguo,ZHANG Mengxi,WANG Weidong.Two stage method for analyzing effects on adjacent metro tunnels due to foundation pit excavation[J].Rock and Soil Mechanics,2011,32(7):2085.
[6]黄栩,黄宏伟,张冬梅.开挖卸荷引起下卧已建盾构隧道的纵向变形研究[J].岩土工程学报,2012,34(7):1241.HUANG Xu,HUANG Hongwei,ZHANG Dongmei.Longitudinal deflection of existing shield tunnels due to deep excavation[J].Chinese Journal of Geotechnical Engineering,2012,34(7):1241.
[7]姜兆华,张永兴.基坑开挖对邻近隧道纵向位移影响的计算方法[J].土木建筑与环境工程,2013,35(1):7.JIANG Zhaohua,ZHANG Yongxing.Calculation of influence on longitudinal deformation of adjacent tunnels due to excavation[J].Journal of Civil Architectural and Environmental Engineering,2013,35(1):7.
[8]ZHANG J F,CHEN J J,WANG J H,et al.Prediction of tunnel displacement induced by adjacent excavation in soft soil[J].Tunnelling and Underground Space Technology,2013,36(2):24.
[9]周泽林,陈寿根,陈亮,等.基坑施工对下卧地铁隧道上抬变形影响的简化理论分析[J].岩土工程学报,2015,37(12):2224.ZHOU Zelin,CHEN Shougen,CHEN Liang,et al.Analysis of uplift deflection of subway tunnel due to adjacent pit excavation[J].Chinese Journal of Geotechnical Engineering,2015,37(12):2224.
[10]梁荣柱,林存刚,夏唐代,等.考虑隧道剪切效应的基坑开挖对邻近隧道纵向变形分析[J].岩石力学与工程学报,2017,36(1):223.LIANG Rongzhu,LIN Cungang,XIA Tangdai,et al.Analysis of the longitudinal deformation of tunnels due to pit excavation considering the tunnel shearing effect[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(1):223.
[11]周泽林,陈寿根,张海生,等.明挖卸荷对下卧地铁双洞隧道变形影响的计算方法研究[J].铁道学报,2016,38(9):109.ZHOU Zelin,CHEN Shougen,ZHANG Haisheng,et al.Calculation method study of deformation effect of underlying double hole subway tunnels in open cutting unloading case[J].Journal of the China Railway Society,2016,38(9):109.
[12]MINDLIN R D.Force at a point in the interior of a semiinfinite solid[J].Physics,1936,7(5):195.
[13]魏纲,赵城丽.基坑开挖引起临近地铁隧道的附加荷载计算方法[J].岩石力学与工程学报,2016,35(增刊1):3408.WEI Gang,ZHAO Chengli.Calculation method of additional load of adjacent metro tunnels due to foundation pit excavation[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(S1):3408.
[14]建筑桩基技术规范:JGJ 94-2008[S].北京:中国建筑工业出版社,2008.Technical code for building pile foundations:JGJ 94-2008[S].Beijing:China Architecture&Building Press,2008.
[15]VESIC A B.Bending of beams resting on isotropic elastic solid[J].Journal of the Engineering Mechanics Division,1961,87(2):35.
[16]徐凌.软土盾构隧道纵向沉降研究[D].上海:同济大学,2005.XU Ling.Study of longitudinal settlement of shield tunnel in soft soil[D].Shanghai:Tongji University,2005.
[17]胡琦,凌道盛,陈云敏.基于Melan解的水平基床系数分析方法及工程运用[J].岩土力学,2009,30(1):34.HU Qi,LING Daosheng,CHEN Yunmin.Analytical method and engineering application of horizontal coefficients of subgrade reaction based on Melan′s solution[J].Rock and Soil Mechanics,2009,30(1):34.