Numerical analysis of excavation disturbance for a large diameter tunnel crossing the Yangtze River considering hydro-mechanical coupling

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Sept.2023, Vol.46 No.9: 1230-1236

DOI: 10.3969/j.issn.1003-5060.2023.09.013

Authors

ZHANG Hongbin $ ^{1} $, LIU Wu $ ^{2} $, SHANG Zhaotao $ ^{1} $,

(Tunnel) Engineering Quality and Safety Supervision Station, Wuhu 241000, China; 2. School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China)

Abstract and Keywords

Abstract: Based on the Yangtze River crossing section in large diameter tunnel project of Wuhu City, the mesoscopic hydro-mechanical coupling model was used to simulate the tunnel excavation responses under the river. The influences of hydro-mechanical coupling effect, structural characteristic of microcracks and supporting water pressure on the tunnel excavation responses were analyzed. The numerical results showed that without considering the hydro-mechanical coupling, the horizontal displacement around the tunnel decreased with the increase of the distance away from the tunnel, while the uplift displacement at the bottom of tunnel was greater than the subsidence at the top. When considering the coupling effect, both the sidewall near the excavated tunnel and the ground surface appeared large horizontal displacement, the subsidence at the top of excavated tunnel increased significantly while the bottom uplift decreased obviously, which was one order of magnitude smaller than the top subsidence. With the increase of water level, the effect of river water seepage on the ground subsidence was more obvious. The structural characteristic of microcracks also had a great influence on the deformation response caused by tunnel excavation. When microcracks were preferentially developed hori-

Keywords: rock mechanics; hydro-mechanical coupling; tunnel excavation; numerical analysis; river-bottom subsidence

作者信息

张红彬 $ ^{1} $，刘武 $ ^{2} $，商兆涛 $ ^{1} $，过申磊 $ ^{2} $，张振华 $ ^{2} $，王佐才 $ ^{2} $

(1. 芜湖市轨道（隧道）交通工程质量安全监督站，安徽芜湖 241000；2. 合肥工业大学土木与水利工程学院，安徽合肥 230009)

摘要和关键词

摘要: 文章以芜湖超大直径过江隧道穿越长江段为例, 采用岩体水力耦合细观力学模型对江底隧道开挖过程进行数值模拟, 分析水力耦合效应、岩体内部微裂纹结构特征及支护水压等对开挖响应的影响。结果表明: 不考虑水力耦合时, 隧道开挖引起的最大水平位移位于隧道两侧, 随着与洞周距离的增大而减小, 隧道底部隆起值大于顶部沉降值, 而考虑水力耦合作用后, 隧道两侧边墙与江底地表均产生较大的水平位移, 隧道顶部沉降显著增大, 底部隆起明显减小, 比顶部沉降小 1 个数量级; 随着江水位增大, 江水渗流作用对江底地面沉降变形影响效应更加明显; 岩体内部初始微裂纹结构特征对隧道开挖引起的江底变形响应影响较大, 优先水平发育时, 水压力降低区域明显增大, 江底地表竖直沉降范围明显扩大, 距离开挖隧道较远区域地表也产生较大沉降变形; 适宜的支护水压可对隧道开挖引起的变形扰动进行有效控制。研究成果对深化涉水隧道水力耦合研究具有一定参考意义。

关键词: 岩体力学；水力耦合；隧道开挖；数值分析；江底沉降

Funding

安徽省自然科学基金资助项目（2208085ME153）；安徽省住房城乡建设科学技术计划资助项目（2021-YF78）

合肥工业大学学报(自然科学版)

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