双隧道不同开挖顺序对临近群桩的影响研究
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摘要
双隧道不同开挖顺序对临近群桩承载性能的影响鲜有报道。针对此问题,采用基于地层损失比的位移控制有限单元法(DCM),对软土地基中不同埋深双隧道不同开挖顺序对处于工作荷载下群桩工作性能的影响进行研究,并与相关离心模型试验结果进行比较。得到以下结论:双隧道不同开挖顺序对群桩桩顶附加沉降和群桩承载能力损失影响差别显著,当先开挖上覆隧道时,群桩桩顶的附加沉降量为先开挖下置隧道时的1.25倍,且群桩承载能力的损失率约为后者的1.2倍;两工况中第二个隧道的开挖使得群桩中前桩附加弯矩和后桩附加弯矩均有明显的增大,此与分居群桩两侧但埋深相同的双隧道开挖对群桩弯矩的影响规律迥异;两工况下均产生较大的附加弯矩和附加轴力,且最大附加弯矩和最大附加轴力均位于上覆隧道轴线附近。
The effects of different tunnel excavation sequences of twin tunneling on exist pile foundation remain to be understood. In this study,a displacement controlled method( DCM) based on ground loss was applied to investigate the problem. Twin tunnels and pile group under working load were located in soft clay. Computation results were compared with the results of the relative centrifuge modeling tests. The following conclusion can be obtained. The effects of construction sequence on the induced settlement of pile group and the apparent loss of pile group capacity are significant. When the construction sequence is the upper tunnel first and then the lower tunnel,the induced settlement of pile group is 1. 25 times of the situation which the construction sequence is in the reverse order. The apparent loss of pile group capacity induced by the former is 1.2 times of the latter. Simultaneously,both of induced bending moment of rear piles and front piles induced by the second tunneling are increased significantly in these two situations. It is contrary to the influence law of the induced bending moment of pile group induced by twin tunneling in the same buried depth located on both side of pile group. Large value of induced bending moment is induced by twin tunneling in the two situations. Both of the maximum values of induced bending moment and the induced axial load are located at the area nearby the axis of the upper tunnel.
The effects of different tunnel excavation sequences of twin tunneling on exist pile foundation remain to be understood. In this study,a displacement controlled method( DCM) based on ground loss was applied to investigate the problem. Twin tunnels and pile group under working load were located in soft clay. Computation results were compared with the results of the relative centrifuge modeling tests. The following conclusion can be obtained. The effects of construction sequence on the induced settlement of pile group and the apparent loss of pile group capacity are significant. When the construction sequence is the upper tunnel first and then the lower tunnel,the induced settlement of pile group is 1. 25 times of the situation which the construction sequence is in the reverse order. The apparent loss of pile group capacity induced by the former is 1.2 times of the latter. Simultaneously,both of induced bending moment of rear piles and front piles induced by the second tunneling are increased significantly in these two situations. It is contrary to the influence law of the induced bending moment of pile group induced by twin tunneling in the same buried depth located on both side of pile group. Large value of induced bending moment is induced by twin tunneling in the two situations. Both of the maximum values of induced bending moment and the induced axial load are located at the area nearby the axis of the upper tunnel.
引文
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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.(Wang Lixin.Research on the influences of closely passing through the pile foundations of large interchange[J].Chinese Journal of Underground Space and Engineering,2016,12(3):761-768.(in Chinese))
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[12]徐中华.上海地区支护结构与主体地下结构相结合的深基坑变形性状研究[D].上海:上海交通大学,2007.(Xu Zhonghua.Deformation behavior of deep excavations supported by permanent structure in shanghai soft deposit[D].Shanghai:Shanghai Jiao Tong University,2007.(in Chinese))
[13]中华人民共和国住房和城乡建设部.建筑基桩检测技术规范(JGJ 106—2014)[S].北京:中国建筑工业出版社,2014.(Minisrtry of Housing and Urbanrural Development of the People’s Republic of China,Technical Code for Testing of Building Foundation Piles(JGJ 106—2014)[S].Beijing:China Building Industry Press,2014.(in Chinese))
[14]Ng C W W,Yau T L Y,Li J H M,et al.New failure load criterion for large diameter bored piles in weathered geomaterials[J].Journal of Geotechnical and Geoenvironmental Engineering,2001,127(6):488-498.
[15]马少坤,Wong K S,吕虎,等.膨胀土地基中隧道施工对群桩影响研究[J].岩土力学,2013:34(11):3055-3060.(Ma Shaokun,Wong K S,Lu Hu,et al.Study of effects of tunnel construction on pile group in expansive soil[J].Rock and Soil Mechanics,2013,34(11):3055-3060.(in Chinese))
[16]Jacobsz S W,Standing J R,Mair R J,et al.Centrifuge modelling of tunnelling near driven piles[J].Soils and Foundations,2004,44(1):49-56.
[17]中华人民共和国住房和城乡建设部.建筑桩基技术规范(JGJ 94—2008)[S].北京:中国建筑工业出版社,2008.(Ministry of Housing and Urban-rural Development of the People’s Republic of China,Technical Code for Building Pile Foundations(JGJ 94—2008)[S].Beijing:China Building Industry Press,2008.(in Chinese)).
[2]Lee C,Chiang K.Responses of single piles to tunneling-induced soil movements in sandy ground[J].Canadian Geotechnical Journal,2007,44(10):1224-1241.
[3]Mroueh H,Shahrour I.Three-dimensional finite element analysis of the interaction between tunneling and pile foundations[J].International Journal for Numerical and Analytical Methods in Geomechanics,2002,26(3):217-230.
[4]Soomro M A,Hong Y,Ng C W W,et al.Load transfer mechanism in pile group due to single tunnel advancement in stiff clay[J].Tunnelling and Underground Space Technology,2015,45:63-72.
[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.(Wang Lixin.Research on the influences of closely passing through the pile foundations of large interchange[J].Chinese Journal of Underground Space and Engineering,2016,12(3):761-768.(in Chinese))
[6]Ng C W W,Soomro M A,Hong Y.Three-dimensional centrifuge modelling of pile group responses to side-byside twin tunnelling[J].Tunnelling and Underground Space Technology,2014,43(7):350-361.
[7]马少坤,陈欣,吕虎,等.不同埋置位置隧道对群桩影响的离心模型试验研究[J].中国公路学报,2015,28(8):67-73.(Ma Shaokun,Chen Xin,LüHu,et al.Centrifuge modeling test of effects of tunnelling with different depths on pile group[J].China Jouranl of Highway and Transport,2015,28(8):67-73.(in Chinese))
[8]Ng C W W,LüH.Effects of the construction sequence of twin tunnels at different depths on an existing pile[J].Canadian Geotechnical Journal,2014,51(2):173-183.
[9]Ng C W W.The state-of-the-art centrifuge modelling of geotechnical problems at HKUST[J].Journal of Zhejiang University SCIENCE A,2014,15(1):1-21.
[10]杜佐龙,黄茂松,李早.基于地层损失比的隧道开挖对临近群桩影响的DCM方法[J].岩土力学,2009,30(10):3043-3047.(Du Zuolong,Huang Maosong,Li Zao.DCM-based on ground loss for response of group piles induced by tunneling[J].Rock and soil mechanics,2009,30(10):3043-3047.(in Chinese))
[11]Park K H.Elastic solution for tunneling-induced ground movements in clays[J].International Journal of Geomechanics,2004,4(4):310-318.
[12]徐中华.上海地区支护结构与主体地下结构相结合的深基坑变形性状研究[D].上海:上海交通大学,2007.(Xu Zhonghua.Deformation behavior of deep excavations supported by permanent structure in shanghai soft deposit[D].Shanghai:Shanghai Jiao Tong University,2007.(in Chinese))
[13]中华人民共和国住房和城乡建设部.建筑基桩检测技术规范(JGJ 106—2014)[S].北京:中国建筑工业出版社,2014.(Minisrtry of Housing and Urbanrural Development of the People’s Republic of China,Technical Code for Testing of Building Foundation Piles(JGJ 106—2014)[S].Beijing:China Building Industry Press,2014.(in Chinese))
[14]Ng C W W,Yau T L Y,Li J H M,et al.New failure load criterion for large diameter bored piles in weathered geomaterials[J].Journal of Geotechnical and Geoenvironmental Engineering,2001,127(6):488-498.
[15]马少坤,Wong K S,吕虎,等.膨胀土地基中隧道施工对群桩影响研究[J].岩土力学,2013:34(11):3055-3060.(Ma Shaokun,Wong K S,Lu Hu,et al.Study of effects of tunnel construction on pile group in expansive soil[J].Rock and Soil Mechanics,2013,34(11):3055-3060.(in Chinese))
[16]Jacobsz S W,Standing J R,Mair R J,et al.Centrifuge modelling of tunnelling near driven piles[J].Soils and Foundations,2004,44(1):49-56.
[17]中华人民共和国住房和城乡建设部.建筑桩基技术规范(JGJ 94—2008)[S].北京:中国建筑工业出版社,2008.(Ministry of Housing and Urban-rural Development of the People’s Republic of China,Technical Code for Building Pile Foundations(JGJ 94—2008)[S].Beijing:China Building Industry Press,2008.(in Chinese)).