软硬不均地层中盾构施工引起的地层隆沉预测
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摘要
将刚度当层法与Mindlin基本解相结合提出双层弹性体系下盾构施工引起地层隆沉的计算方法,该计算方法可以同时考虑开挖面处不平衡力、盾壳–土体间摩擦力、盾尾同步注浆压力、二次补偿注浆压力、施工期间地层附加荷载及地层损失6个施工因素对地层隆沉的贡献,同时可以反映上下地层刚度差异对地层隆沉的影响。研究发现,当盾构浅埋时,其在上下刚度不均地层中掘进引起的地表隆沉与其在单一软或单一硬地层中掘进引起的隆沉差别较大;当盾构埋深逐渐增大时,这个值逐渐接近盾构在单一软地层及单一硬地层中掘进引起隆沉的平均值,此外研究发现,二次注浆范围从全断面至未注浆变化时,地层的隆起值先增大后减小最后变为0,当注浆范围为上半断面时,注浆补偿效果最好。从京张高铁清华园隧道的实测数据与理论计算对比分析可以发现:提出的双地层模型可以较好地反映开挖面前方地表的隆起及开挖面后方先沉降后隆起再稳定的规律,且比基于单一地层模型采用加权平均法计算得到的隆沉值更接近实测值,计算误差可减小11.08%。研究成果可为盾构在单一地层及软硬不均双层地层中施工引起的地层隆沉的预测提供理论指导。
A method for calculating ground vertical displacements of double-layor elastic system due to shield tunneling was proposed combining the stiffness equivalent method with the Mindlin solution,which can simultaneously consider the unbalanced force at the tunnel face,the friction between the shield skin and the soil,the grouting pressure of the shield tail,the secondary grouting pressure,the additional load during tunnelling and the volume loss,and can also reflect the influence of the stiff difference of adjacent layers on ground displacements. The results show that the calculated ground vertical displacement induced by tunnelling in double-layer soil is different from that in single-layer soil while the overburden thickness is shallower,and close to the average value of the ground displacements calculated in soft and hard layers when the overburden thickness is getting deeper. It is also shown that the ground heave value first increases,then decreases and finally goes to zero with the secondary grouting ranging from the full face to the ungrouted zone and that the optimal grouting range is within the upper half. Comparisons between the ground vertical displacements of the field measurement and the theoretical calculation of Qinghuayuan Tunnel of the Jing-Zhang High Speed Railway indicate that the proposed double-layer model can describe the pattern of soil heave ahead of the tunnel face and settle-heave-stabilization behind of the tunnel face and that the calculated value of the ground vertical displacement by the model is much closer to the measured value than that calculated using single-layer model and the calculation error is reduced by 11.08%. The research results can provide a theoretical support for predicting ground vertical displacements caused by shield tunnelling both in single-layer soil and double-layer soil.
A method for calculating ground vertical displacements of double-layor elastic system due to shield tunneling was proposed combining the stiffness equivalent method with the Mindlin solution,which can simultaneously consider the unbalanced force at the tunnel face,the friction between the shield skin and the soil,the grouting pressure of the shield tail,the secondary grouting pressure,the additional load during tunnelling and the volume loss,and can also reflect the influence of the stiff difference of adjacent layers on ground displacements. The results show that the calculated ground vertical displacement induced by tunnelling in double-layer soil is different from that in single-layer soil while the overburden thickness is shallower,and close to the average value of the ground displacements calculated in soft and hard layers when the overburden thickness is getting deeper. It is also shown that the ground heave value first increases,then decreases and finally goes to zero with the secondary grouting ranging from the full face to the ungrouted zone and that the optimal grouting range is within the upper half. Comparisons between the ground vertical displacements of the field measurement and the theoretical calculation of Qinghuayuan Tunnel of the Jing-Zhang High Speed Railway indicate that the proposed double-layer model can describe the pattern of soil heave ahead of the tunnel face and settle-heave-stabilization behind of the tunnel face and that the calculated value of the ground vertical displacement by the model is much closer to the measured value than that calculated using single-layer model and the calculation error is reduced by 11.08%. The research results can provide a theoretical support for predicting ground vertical displacements caused by shield tunnelling both in single-layer soil and double-layer soil.
引文
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[4]SUN J,LIU J.Visualization of tunnelling-induced ground movement in transparent sand[J].Tunnelling and Underground Space Technology,2014,40(40):236-240.
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[12]施成华,彭立敏,雷明锋.盾构法施工隧道地层变形时空统一预测方法研究[J].岩土力学,2009,30(8):2 379-2 384.(SHI Chenghua,PENG Limin,LEI Mingfeng.Study of time-space united calculating method of stratum deformation caused by shield tunnel excavation[J].Rock and Soil Mechanics,2009,30(8):2 379-2 384.(in Chinese))
[13]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.(in Chinese))
[14]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):2 583-2 592.(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):2 583-2 592.(in Chinese))
[15]梁荣柱,夏唐代,林存刚,等.盾构推进引起地表变形及深层土体水平位移分析[J].岩石力学与工程学报,2015,34(3):583-593.(LIANG Rongzhu,XIA Tangdai,LIN Cungang,et al.Analysis of 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.(in Chinese))
[16]龚晓南.土力学[M].北京:中国建筑工业出版社,2002:73-74.(GONG Xiaonan.Soil mechanics[M].Beijing:China Architecture and Building Press,2002:73-74.(in Chinese))
[17]刘建航,侯学渊.盾构法隧道[M].北京:中国铁道出版社,1991:329-333.(LIU Jianhang,HOU Xueyuan.Shield tunnelling method[M].Beijing:China Railway Publishing House,1991:329-333.(in Chinese))
[18]张云,殷宗泽,徐永福.盾构法隧道引起的地表变形分析[J].岩石力学与工程学报,2002,21(3):388-392.(ZHANG Yun,YINZhongze,XU Yongfu.Analysis on three-dimensional ground surface deformations due to shield tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(3):388-392.(in Chinese))
[19]GONZáLEZ C,SAGASETA C.Patterns of soil deformations around tunnels:Application to the extension of Madrid Metro[J].Computers and Geotechnics,2001,28(6/7):445-468.
[20]朱忠隆,张庆贺,易宏传.软土隧道纵向地表沉降的随机预测方法[J].岩土力学,2001,22(1):56-59.(ZHU Zhonglong,ZHANG Qinghe,YI Hongchuan.Stochastic theory for predicting longitudinal settlement in soft-soil tunnel[J].Rock and Soil Mechanics,2001,22(1):56-59.(in Chinese))
[21]项彦勇.隧道力学概论[M].北京:科学出版社,2014:135-136.(XIANG Yanyong.General theory of tunnel mechanics[M].Beijing:Science Press,2014:135-136.(in Chinese))
[22]张治国,白乔木,赵其华.带衬砌浅埋隧道开挖受非对称收敛变形影响的地层位移和衬砌应力分析[J].岩石力学与工程学报,2016,35(6):1 202-1 213.(ZHANG Zhiguo,BAI Qiaomu,ZHAO Qihua.Elastic analysis of ground displacement and liner stress induced by shallow shield excavation considering non-uniform convergence deformation with liner[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(6):1 202-1 213.(in Chinese))
[23]LEE K M,ROWE R K,LO K Y.Subsidence owing to tunnelling.I.Estimating the gap parameter[J].Canadian Geotechnical Journal,1992,29(6):929-940.
[24]韩煊,李宁.隧道施工引起地层位移预测模型的对比分析[J].岩石力学与工程学报,2007,26(3):594-600.(HAN Xuan,LI Ning.Comparative analysis of strata prediction models for ground movement induced by tunnel construction[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(3):594-600.(in Chinese))
[25]魏纲.盾构法隧道地面沉降槽宽度系数取值的研究[J].工业建筑,2009,39(12):74-79.(WEI Gang.Study on calculation for width parameter of surface settlement trough induced by shield tunnel[J].Industrial Construction,2009,39(12):74-79.(in Chinese))
[2]阳军生.城市隧道施工引起的地表移动及变形[M].北京:中国铁道出版社,2002:10-51.(YANG Junsheng.Movements and displacements due to tunneling in urban areas[M].Beijing:China Railway Publishing House,2002:10-51.(in Chinese))
[3]KAVVADAS M,LITSAS D,VAZAIOS I,et al.Development of a 3Dfinite element model for shield EPB tunnelling[J].Tunnelling and Underground Space Technology,2017,65(5):22-34.
[4]SUN J,LIU J.Visualization of tunnelling-induced ground movement in transparent sand[J].Tunnelling and Underground Space Technology,2014,40(40):236-240.
[5]MAIR R J.Subsurface settlement profiles above tunnels in clays[J].Géotechnique,1993,43(2):361-362.
[6]司金标,朱瑶宏,季昌,等.软土层中类矩形盾构掘进施工引起地层竖向变形实测与分析[J].岩石力学与工程学报,2017,36(6):1 551-1 559.(SI Jinbiao,ZHU Yaohong,JI Chang,et al.Measurement and analysis of vertical deformation of stratum induced by quasirectangular shield tunneling in soft ground[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(6):1 551-1 559.(in Chinese))
[7]SAGASETA C.Analysis of undrained soil deformation due to ground loss[J].Géotechnique,1987,37(3):301-320.
[8]PARK K H.Analytical solution for tunnelling-induced ground movement in clays[J].Tunnelling and Underground Space Technology,2005,20(3):249-261.
[9]VERRUIJT A.Complex variable solution for a deforming circular tunnel in an elastic half plane[J].Géotechnique,1997,21(4):77-89.
[10]MINDLIN R D.Force at a point in the interior of a semi-infinite solid[J].Journal of Applied Physics,1936,7(5):195-202.
[11]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):1 077-1 081.(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):1 077-1 081.(in Chinese))
[12]施成华,彭立敏,雷明锋.盾构法施工隧道地层变形时空统一预测方法研究[J].岩土力学,2009,30(8):2 379-2 384.(SHI Chenghua,PENG Limin,LEI Mingfeng.Study of time-space united calculating method of stratum deformation caused by shield tunnel excavation[J].Rock and Soil Mechanics,2009,30(8):2 379-2 384.(in Chinese))
[13]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.(in Chinese))
[14]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):2 583-2 592.(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):2 583-2 592.(in Chinese))
[15]梁荣柱,夏唐代,林存刚,等.盾构推进引起地表变形及深层土体水平位移分析[J].岩石力学与工程学报,2015,34(3):583-593.(LIANG Rongzhu,XIA Tangdai,LIN Cungang,et al.Analysis of 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.(in Chinese))
[16]龚晓南.土力学[M].北京:中国建筑工业出版社,2002:73-74.(GONG Xiaonan.Soil mechanics[M].Beijing:China Architecture and Building Press,2002:73-74.(in Chinese))
[17]刘建航,侯学渊.盾构法隧道[M].北京:中国铁道出版社,1991:329-333.(LIU Jianhang,HOU Xueyuan.Shield tunnelling method[M].Beijing:China Railway Publishing House,1991:329-333.(in Chinese))
[18]张云,殷宗泽,徐永福.盾构法隧道引起的地表变形分析[J].岩石力学与工程学报,2002,21(3):388-392.(ZHANG Yun,YINZhongze,XU Yongfu.Analysis on three-dimensional ground surface deformations due to shield tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(3):388-392.(in Chinese))
[19]GONZáLEZ C,SAGASETA C.Patterns of soil deformations around tunnels:Application to the extension of Madrid Metro[J].Computers and Geotechnics,2001,28(6/7):445-468.
[20]朱忠隆,张庆贺,易宏传.软土隧道纵向地表沉降的随机预测方法[J].岩土力学,2001,22(1):56-59.(ZHU Zhonglong,ZHANG Qinghe,YI Hongchuan.Stochastic theory for predicting longitudinal settlement in soft-soil tunnel[J].Rock and Soil Mechanics,2001,22(1):56-59.(in Chinese))
[21]项彦勇.隧道力学概论[M].北京:科学出版社,2014:135-136.(XIANG Yanyong.General theory of tunnel mechanics[M].Beijing:Science Press,2014:135-136.(in Chinese))
[22]张治国,白乔木,赵其华.带衬砌浅埋隧道开挖受非对称收敛变形影响的地层位移和衬砌应力分析[J].岩石力学与工程学报,2016,35(6):1 202-1 213.(ZHANG Zhiguo,BAI Qiaomu,ZHAO Qihua.Elastic analysis of ground displacement and liner stress induced by shallow shield excavation considering non-uniform convergence deformation with liner[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(6):1 202-1 213.(in Chinese))
[23]LEE K M,ROWE R K,LO K Y.Subsidence owing to tunnelling.I.Estimating the gap parameter[J].Canadian Geotechnical Journal,1992,29(6):929-940.
[24]韩煊,李宁.隧道施工引起地层位移预测模型的对比分析[J].岩石力学与工程学报,2007,26(3):594-600.(HAN Xuan,LI Ning.Comparative analysis of strata prediction models for ground movement induced by tunnel construction[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(3):594-600.(in Chinese))
[25]魏纲.盾构法隧道地面沉降槽宽度系数取值的研究[J].工业建筑,2009,39(12):74-79.(WEI Gang.Study on calculation for width parameter of surface settlement trough induced by shield tunnel[J].Industrial Construction,2009,39(12):74-79.(in Chinese))