Research on stability of excavation face of shield tunnel undercrossing station in water-rich gravel stratum
XIAO Pengfei1, FENG Guangfu1, JIA Shaodong1, MENG Qingjun1, WANG Shuying2, LIU Aolin2
1. Nanning Rail Transit Co., Ltd., Nanning 530000, Guangxi, China; 2. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China
Abstract: Based on the project of Nanning Metro Line 5 undercrossing Guangxi University Station of Line 1 in Xinguang Section, FLAC3D software was used to study the stability of the excavation face of the shield tunnel undercrossing the water-rich gravel stratum of the station bottom plate at ultra-close distance. The influence of support stress ratio and groundwater level on the stability of excavation face was explored, and the appropriate supporting pressure control value of excavation face was given as the technical guidance for field construction. The research showed that with the decrease of the support stress ratio, the horizontal displacement of the soil on the excavation face increased continuously, and its deformation conformed to the development trend of the soil plastic zone. The failure mode of the excavation face in the water-rich gravel stratum was wedge-shaped ahead of the excavation, and the failure area gradually developed to the bottom plate of the existing station structure. After the instability and failure of the excavation face, the bottom plate of the station structure and the soil belowed the bottom plate form the free surface; with the increase of groundwater level, the supporting stress ratio of instability failure of excavation face increased, and the stability of excavation face decreased significantly. The earth pressure should be controlled above 111 kPa when crossing station.
肖鹏飞, 冯光福, 贾少东, 孟庆军, 王树英, 刘奥林. 近距离下穿车站富水圆砾地层盾构隧道开挖面稳定性研究[J]. 隧道与地下工程灾害防治, 2021, 3(1): 75-81.
XIAO Pengfei, FENG Guangfu, JIA Shaodong, MENG Qingjun, WANG Shuying, LIU Aolin. Research on stability of excavation face of shield tunnel undercrossing station in water-rich gravel stratum. Hazard Control in Tunnelling and Underground Engineering, 2021, 3(1): 75-81.
[1] BROMS B B, BENNERMARK H. Stability of clay at vertical openings[J]. Journal of Soil Mechanics and Foundations Division, 1967, 96(1): 71-94. [2] JANSSEN H A. Versuche uber getreidedruck in silozellen[J]. Seitschrift Des Vereins Deutscher Ingenieure, XXX-IX, 1895, 35: 1045-1049. [3] DAVIS E H, GUNN M J, MAIR R J, et al. The stability of shallow tunnels and underground openings in cohesive material[J]. Géotechnique, 1980, 30(4): 397-416. [4] DE BUHAN P, CUVILLIER A, DORMIEUX L, et al. Face stability of shallow circular tunnels driven under the water table: a numerical analysis[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 1999, 23(1): 79-95. [5] CHAMBON P, CORTÉ J F. Shallow tunnels in cohesionless soil: stability of tunnel face[J]. Journal of Geotechnical Engineering, 1994, 120(7): 1148-1165. [6] KIRSCH A.Experimental investigation of the face stability of shallow tunnels in sand[J]. Acta Geotechnica, 2010, 5(1):43-62. [7] TAKANO D, OTANI J, NAGATANI H, et al. Application of X-Ray CT on boundary value problems in geotechnical engineering: research on tunnel face failure[C] //Proceedings of the Geo-Congress.Atlanta, USA:the Geo-Institute of the ASCE, 2006. [8] 陈仁朋,齐立志,汤旅军,等.砂土地层盾构隧道开挖面被动破坏极限支护力研究[J].岩石力学与工程学报,2013,32(增刊1):2877-2882. CHEN Renpeng, QI Lizhi, TANG Lüjun, et al. Study of limit supporting force of excavation face's passive failure of shield tunnels in sand strata[J].Chinese Journal of Rock Mechanics and Engineering, 2013, 32(Suppl.1):2877-2882. [9] 邱龑,杨新安,徐前卫,等. 富水砂层盾构隧道开挖面稳定性及其失稳风险的分析[J].中国铁道科学, 2015, 36(6):55-62. QIU Yan, YANG Xinan, XU Qianwei, et al. Analysis on stability and instability risk of excavation face of shield tunnel in water-rich sand layer[J].China Railway Science, 2015, 36(6):55-62. [10] 康志军,谭勇,李金龙. 基于流-固耦合的盾构隧道开挖面稳定性研究[J].隧道建设(中英文), 2017, 37(10): 1287-1295. KANG Zhijun, TAN Yong, LI Jinlong. Numerical study of working face stability of shield tunnel based on fluid-solid coupling effect[J].Tunnel Construction, 2017, 37(10): 1287-1295. [11] 黄振恩,吴俊,张洋,等. 考虑流固耦合效应的盾构隧道开挖面稳定性研究[J].现代隧道技术, 2018,55(5):61-71. HUANG Zhen'en, WU Jun, ZHANG Yang, et al. Analysis of the stability of the shield tunnel excavation face considering fluid-solid coupling effect[J]. Modern Tunnelling Technology, 2018, 55(5):61-71. [12] 秦建设.盾构施工开挖面变形与破坏机理研究[D].南京: 河海大学, 2005. QIN Jianshe. Study on face deformation and collapse of earth pressure shield tunnel[D]. Nanjing:Hohai University, 2005. [13] 邱明明, 姜安龙, 舒勇. 城市地铁盾构施工地层变形三维数值模拟分析[J].防灾减灾工程学报, 2014,34(2): 161-167. QIU Mingming, JIANG Anlong, SHU Yong. Three-dimensional numerical simulation analysis of stratum deformation induced by subway shield construction[J].Journal of Disaster Prevention and Mitigation Engineering, 2014, 34(2): 161-167. [14] 付亚雄,贺雷,马险峰,等. 软黏土地层盾构隧道开挖面稳定性离心试验研究[J].地下空间与工程学报, 2019, 15(2): 387-393. FU Yaxiong, HE Lei, MA Xianfeng, et al. Centrifuge model tests on face stability of shield tunneling in soft clay[J]. Chinese Journal of Underground Space and Engineering, 2019, 15(2): 387-393. [15] 亢晨钢. 盾构机密封舱压力分布数值模拟[D].大连:大连理工大学,2010. KANG Chengang. Numerical simulation of earth pressure distribution in head chamber of EPB shield machine[D]. Dalian:Dalian University of Technology, 2010.
2021, Vol. 3 
