铁道科学与工程学报2025，Vol.22Issue(1)：295-306,12.DOI:10.19713/j.cnki.43-1423/u.T20240429
渗流效应下富水粉砂地层盾构隧道端头开挖安全性分析
Safety analysis of end excavation of shield tunnels in water-rich and silty strata subjected to seepage effect
摘要
Abstract
For shield tunneling in water-rich stratum,the breaking of tunnel portal prior to departure or arrival may cause the destabilization soils.To analyze the security of shield tunnel ends in water-rich stratum and avoid the collapse,the empirical hydraulic head formula was introduced to describe the distribution of water head near shield tunnel faces.The complex 3D seepage problem was simplified to a 2D by ignoring the influence of seepage on the cross section.A 2D seepage field near shield tunnel faces in the water-rich stratum was created.Assuming the hydrostatic head remains constant in the seepage process,the collapse failure mechanism of shield tunnel ends in the water-rich silty sand stratum was established by combining the 2D seepage model with the limit analysis method.The seepage force power and the gravity power inducing damage and the internal energy dissipation rate that resist damage were deduced.An optimal upper limit solution of the safety factor was solved by the exhaustive algorithm.The results show that,the security of shield tunnel ends is found to depend significantly on the head difference,the shear strength index,the excavation diameter and the buried depth ratio.When the head difference is assumed to be zero,the security of the shield tunnel ends will be significantly overestimated.Comparing with the non-precipitation conditions,the security of shield tunnel ends after the precipitation treatment is greatly improved and it is in a security state.Besides,the security is no longer related to the buried depth,but depends on the shear strength and the excavation diameter.The results have been successfully applied to Changsha Metro Line 5 and Line 2,and the security of the strata at the end of water-rich shield tunnels before and after the precipitation was analyzed,and the rationality of the treatment scheme is also verified.This methodology can provide theoretical guidance for the security analysis of shield tunnel ends in water-rich stratum in the future.关键词
盾构隧道端头/渗透力/安全系数/降水/地下水位线Key words
end of shield tunnel/seepage force/safety factor/precipitation/ground water line分类
交通工程引用本文复制引用
张佳华,杨小丽,蒋贤勇,张道兵,张标..渗流效应下富水粉砂地层盾构隧道端头开挖安全性分析[J].铁道科学与工程学报,2025,22(1):295-306,12.基金项目
国家自然科学基金资助项目(52074116) （52074116）
湖南省教育厅科学研究优秀青年项目(23B0476) （23B0476）
