基于流固耦合理论的连拱隧道围岩稳定性分析

以湖南省常吉高速公路新修建的一些大跨度连拱隧道为工程背景，基于流固耦合分析理论，利用快速拉格朗日有限差分法对连拱隧道围岩稳定性进行分析。主要考虑流固耦合效应作用时，围岩级别、隧道埋深、地下水位以及施工工法和初期支护等因素对围岩稳定性的综合影响，得到Ⅲ，Ⅳ，Ⅴ级围岩在各种情况下隧道开挖后围岩最大主应力、洞周位移、塑性区、孔隙水压力分布以及喷锚支护受力特征等结果，探讨连拱隧道开挖渗流机制，并分析深埋连拱隧道开挖后的孔隙水压力场分布特征。研究结果直接指导该高速公路二期工程中的隧道防排水施工和支护措施的改进提高，为富水地层条件下的隧道工程开挖设计提供一定的理论参考。

STABILITY ANALYSIS OF SURROUNDING ROCK OF MULTI-ARCH TUNNEL BASED ON COUPLED FLUID-SOLID THEOREM

Along the freeway from Changde to Jishou in Hunan Province,some large span multi-arch tunnels have been built to meet the need of engineering.Based on the coupled fluid-solid theorem,numerical analysis for the stability of surrounding rock has been done with fast Lagrangian analysis of continua in three-dimension(FLAC3D) by considering the multiple factors including surrounding rock classes,tunnel depths,groundwater tables,construction methods and initial supporting systems.According to the numerical analysis of surrounding rock with classes III,IV,V under all kinds of calculation cases,the results of principal stresses,displacements,plastic zones,pore pressure distribution and the mechanical characters of supporting system including anchors and shotcrete,have been obtained.The seepage mechanism of multi-arch tunnel has been discussed;and the pore pressure distribution of deep-buried tunnel has been studied.The achieved results are successfully applied to guidance of the tunnel construction for waterproofing of this freeway.Furthermore,the study results can provide a theoretical basis for the design of multi-arch tunnel in aquifer strata.