Kinematic analysis of shallow tunnel in layered strata considering joined effects of settlement and seepage

Abstract

The purpose of this work is to predict the state of collapse in shallow tunnel in layered strata by using a new curved failure mechanism within the framework of upper bound theorem. Particular emphasis is first given to consider the effects of seepage forces and surface settlement. Furthermore, the Hoek-Brown nonlinear failure criterion is adopted to analyze the influence of different factors on the collapsing shape. Two different curve functions which describe two different rock layers are obtained by virtual work equations under the variational principle. According to the numerical results, the parameter B in Hoek-Brown failure criterion and the unit weights in different rock layers have a positive relationship with the size of collapsing block while pore pressure coefficient and the parameter A in Hoek-Brown failure criterion present a reverse tend.

摘要

极限分析是一种预测岩土工程稳定性的重要工具。 近年来随着隧道工程的发展, 关于浅埋隧道开挖中地下水对隧道顶部稳定性的研究越来越重要。 在本文中, 作者探究了孔隙水压力和表面地表沉降共同作用下浅埋隧道顶部在层状岩层中的破坏模式。 本研究应用上限分析理论, 并采用 Hoek-Brown 非线性破坏准则来探索不同因素对浅埋隧道破坏模式和支护系统的影响。 以双层岩层为例, 通过两条不同的非线性破坏面的引入, 本文得到了描述层状岩石层中不同的隧道破坏模式。 本文另一创新是通过固体力学变分法得到强非线性方程, 并通过数值方法得到浅埋隧道的破坏模式。 另外本文深入探索了不同参数对隧道破坏模式的影响。 通过数据和画图的形式讨论了不同因素对隧道破坏模式的影响。