Stability Analysis of Tunnel Construction in Water-rich and Weakly Cemented Sandstone Formations
侯宗政 HOU Zong-zheng
（中铁第五勘察设计院集团有限公司，北京 102600）
（China Railway Fifth Survey and Design Institute Group Co.，Ltd.，Beijing 102600，China）
摘要：针对富水弱胶结砂岩地层隧道施工，以中兰铁路香山隧道为工程背景，通过数值模拟对不同天然水位线高度下隧道模型的渗流场和位移场进行了分析，研究了水位变化对隧道围岩稳定性的影响。结果表明：不采用降水措施进行隧道施工时，隧道出现临空面，被挖空隧道部位孔隙水压力为 0，形成漏斗形渗流场，随着水位的增高，水力梯度会增大，隧道围岩位移场呈非线性增速增涨。新近系弱胶结砂岩在自身胶结性较弱、处在自然水位线下的芋级弱胶结砂岩等级时，施工需考虑采用其他辅助工法如超前注浆、提前降水等配合施工。
Abstract: Aiming at the tunnel construction in water-rich weakly cemented sandstone strata, taking the Xiangshan Tunnel of the Zhongwei-lanzhou Railway as the engineering background, the seepage field and displacement field of the tunnel model under different heights of the natural water level line were analysed through numerical simulation, and the influence of water level changes on the stability of the tunnel surrounding rock was investigated. The results show that: when the tunnel construction is carried out without water reduction measures, the tunnel appears to have a critical surface, and the pore water pressure in the excavated tunnel part is 0, forming a funnelshaped seepage field, and as the water level increases, the hydraulic gradient will increase, and the displacement field of the tunnel peripheral rock shows a nonlinear incremental increase. New recent system of weakly cemented sandstone in its own weak cementation, in the natural water level line under the 芋 weakly cemented sandstone grade, the construction needs to consider the use of other auxiliary methods such as overrun grouting, early precipitation and so on with the construction.
关键词：富水弱胶结砂岩；稳定性；渗流场；位移场
Key words: water-rich weakly cemented sandstone；stability；seepage field；displacement field
中图分类号： U451+.2 文献标识码：A 文章编号：1006-4311（2024）28-121-04 doi:10.3969/j.issn.1006-4311.2024.28.036
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