Upper bound analysis for estimation of the influence of seepage on tunnel face stability in layered soils

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• 作者：Wei Liu ; Bettina Albers ; Yu Zhao ; Xiao-wu Tang
• 关键词：Face stability ; Upper bound analysis ; Support pressure ; Groundwater seepage ; Layered soils
• 刊名：Journal of Zhejiang University-SCIENCE A
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：17
• 期：11
• 页码：886-902
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Mechanical Engineering; Civil Engineering; Classical and Continuum Physics; Industrial Chemistry/Chemical Engineering;
• 出版者：Zhejiang University Press
• ISSN：1862-1775
• 卷排序：17

文摘

Tunnel face stability is important for safe tunneling and the protection of the surrounding environment. Upper bound analysis is a widely applied method to investigate tunnel face stability. In this paper, a tunnel face collapse of Guangzhou metro line 3 is presented. Accordingly, seepage is considered in the upper bound solutions for face stability in layered soils. Steady-state seepage is reached in the first 1200 s of each drilling step. In the crossed layer, the seepage flow is horizontal toward the tunnel face, whereas in the cover layer, the seepage vertically percolates into the crossed layer. By considering the seepage forces on the tunnel face and on the soil particles, the upper bound solution for the support pressure needed for face stability in layered soil with seepage is obtained. Under saturated conditions, the support pressure is influenced by the variation of the depth ratio due to the seepage effect. Moreover, the support pressure depends linearly on the groundwater level. This study provides estimations of the support pressure for face stability in tunnel design.