砂卵石地层盾构近距离侧穿匝道桥桩变形研究
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摘要
近年来,地下空间开发所带来的环境问题受到广泛关注,其中隧道穿越既有建筑和桥梁基础的近接施工问题尤为突出。本文针对北京地铁16号线垂直下穿肖家河立交B、C匝道桥,利用FIAC3D进行盾构侧穿桩基数值模拟,研究了盾构掘进过程中桩基产生的横向变形、纵向变形、以及开挖完成后的桩基沉降规律,并结合墩柱实测沉降数据对侧穿桥桩的保护措施进行研究。结果表明:砂卵石地层盾构侧穿引起桩的变形主要由正向推力和侧向挤压力造成,主要影响范围在距桩前后各12 m;桩顶沉降普遍大于横向和纵向变形,刀盘穿过桩基后,桩顶沉降曲线斜率加剧,呈陡降趋势;在影响范围内采用隧道全周深孔注浆,有效地减小了桩基沉降,并将其控制在允许值内。研究结果为保证盾构安全穿越、防止匝道桥沉降过大提供了重要的理论依据。
In recent years,the environmental problems caused by the development of underground space have received extensive concern.The problem of proximity construction of tunnels crossing existing buildings and bridge foundations is particularly problematic.Based on the shield construction of Beijing Metro Line 16 which crosses under Xiaojiahe B and C interchange ramp bridge vertically,FLAC3 Dnumerical simulation was employed to study the regulation of lateral deformation,longitudinal deformation of pile foundations in the process of shield side-crossing the pile foundations and the settlement regulation after excavation.Besides,protective measures were studied combined with field monitoring settlement data.The results show that the deformation induced by side-crossing shield construction is mainly caused by forward thrust and lateral extrusion pressure in sandy cobble stratum,and the main influence range of pile deformation is both 12 m before and after the piles.The settlement of pile foundation is generally greater than lateral deformation and longitudinal deformation.After the cutterhead passed through the pile foundations,the slope of the settlement curve is intensified and appears as a steep decline.The deep hole grouting around the tunnel can be effectively employed to reduce the settlement of the pile foundation within the influence range and control the displacement within the allowable value.The study provides certain significant theoretical reference for shield tunneling security and the prevention of the overlarge bridge settlement.
In recent years,the environmental problems caused by the development of underground space have received extensive concern.The problem of proximity construction of tunnels crossing existing buildings and bridge foundations is particularly problematic.Based on the shield construction of Beijing Metro Line 16 which crosses under Xiaojiahe B and C interchange ramp bridge vertically,FLAC3 Dnumerical simulation was employed to study the regulation of lateral deformation,longitudinal deformation of pile foundations in the process of shield side-crossing the pile foundations and the settlement regulation after excavation.Besides,protective measures were studied combined with field monitoring settlement data.The results show that the deformation induced by side-crossing shield construction is mainly caused by forward thrust and lateral extrusion pressure in sandy cobble stratum,and the main influence range of pile deformation is both 12 m before and after the piles.The settlement of pile foundation is generally greater than lateral deformation and longitudinal deformation.After the cutterhead passed through the pile foundations,the slope of the settlement curve is intensified and appears as a steep decline.The deep hole grouting around the tunnel can be effectively employed to reduce the settlement of the pile foundation within the influence range and control the displacement within the allowable value.The study provides certain significant theoretical reference for shield tunneling security and the prevention of the overlarge bridge settlement.
引文
[1]李新星,杨志豪.盾构近距离穿越高架桩基的施工影响与保护措施[J].岩土力学,2015,36(增1):537-541.
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[5]王立新.盾构超近距离穿越大型立交桩基群影响研究[J].地下空间与工程学报,2016,12(3):761-768.
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[11]Ong C W,Leung C F,Chow Y K.Experimental study of tunnel-soil-pile interaction[A]//Proceedings of Underground Singapore[C].Singapore:National University of Singapore,2007:256-263.
[12]陈育民.FLAC及FLAC3D基础与工程实例[M].北京:中国水利水电出版社,2009.
[13]Itasca Consulting Group Inc.Fast lagrangian analysis of continua in 3 dimensions,version 3.0,users'manual[M].Minneapolis:Itasca Consulting Group Inc.2002.
[14]宋卫东,陈瑞宏,杜建华,等.北京地铁10号线国贸-双井区间土压平衡盾构施工数值模拟研究[J].岩石力学与工程学报,2008,27(增2):3401-3407.
[15]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,1997,25(3):274-280.
[16]李大勇,宋言江,李德胜.单桩对临近盾构机侧向穿越时的响应[J].岩土工程学报,2011,33(增2):150-154.
[2]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.
[3]袁海平,王斌,朱大勇,等.盾构近距侧穿高架桥桩的施工力学行为研究[J].岩石力学与工程学报,2014,33(7):1457-1464.
[4]胡德华,段景川.盾构掘进对邻近桩基的变形特征研究[J].隧道建设,2015,35(5):413-418.
[5]王立新.盾构超近距离穿越大型立交桩基群影响研究[J].地下空间与工程学报,2016,12(3):761-768.
[6]朱逢斌,杨平,Ong C W.盾构隧道开挖对邻近桩基影响数值分析[J].岩土工程学报,2008,30(2):298-302.
[7]Chen L T,Poulos H G,Loganathan N.Pile responses caused by tunneling[J].Journal of Geotechnical and Geoenvironmental Engineering,1999,125(3):207-215.
[8]黄茂松,李早,杨超.隧道开挖条件下被动群桩遮拦效应分析[J].土木工程学报,2007,40(6):69-74.
[9]Loganathan N,Poulos H G,Xu K J.Ground and pilegroup response due to tunneling[J].Soils and Foundations,2001,41(1):57-67.
[10]Jacobsz S W,Bowers K H,Moss N A,et al.The effects of tunneling on piled structures on the CTRL[A]//5th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground[C].Amsterdam:Taylor&Francis,2005:15-17.
[11]Ong C W,Leung C F,Chow Y K.Experimental study of tunnel-soil-pile interaction[A]//Proceedings of Underground Singapore[C].Singapore:National University of Singapore,2007:256-263.
[12]陈育民.FLAC及FLAC3D基础与工程实例[M].北京:中国水利水电出版社,2009.
[13]Itasca Consulting Group Inc.Fast lagrangian analysis of continua in 3 dimensions,version 3.0,users'manual[M].Minneapolis:Itasca Consulting Group Inc.2002.
[14]宋卫东,陈瑞宏,杜建华,等.北京地铁10号线国贸-双井区间土压平衡盾构施工数值模拟研究[J].岩石力学与工程学报,2008,27(增2):3401-3407.
[15]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,1997,25(3):274-280.
[16]李大勇,宋言江,李德胜.单桩对临近盾构机侧向穿越时的响应[J].岩土工程学报,2011,33(增2):150-154.