基于仰拱缺陷及膨胀围岩作用下的运营隧道衬砌安全性评价分析

Analysis on Safety Evaluation of Operating Tunnel Lining Based on Inverted Arch Defects and Expansive Surrounding Rock

针对辽宁省西部地区某高速运营隧道出现的检修道隆起及边墙收敛病害,在专项检测及地质勘察的基础上,结合现场实际病害特征建立数值分析模型,分析隧道衬砌在有无仰拱状态及膨胀围岩带来外部荷载增大状态的衬砌结构安全性。结果表明:仰拱结构对于衬砌安全起着至关重要的作用,在无仰拱的状态下,结构弯矩较大,导致安全系数不足,仰拱结构在很大程度上削弱了结构受弯效应,提高了结构安全系数;仰拱结构很好地抑制了外荷载作用下的拱脚部位结构变形,降低了结构收敛量。膨胀压力所带来的外荷载增大,主要集中在右拱腰及右侧边墙范围,在实际工程中应考虑其影响范围,通过计算分析为病害处治提供参考。

In response to the problem of maintenance road uplift and side wall convergence disease in a high-speed operating tunnel in the western region of Liaoning province,the numerical analysis model is established based on special inspection and geological survey and in combination with the actual disease characteristics on site,so as to analyze the safety of the tunnel lining structure in the presence or absence of inverted arches and the external load increase caused by the expansive surrounding rock.The results show that:the inverted arch structure plays a crucial role in the safety of the lining.In the absence of an inverted arch,the structural bending moment is large,leading to insufficient safety factors.The inverted arch structure greatly weakens the structural bending effect and improves the safety factor of the structure;the inverted arch structure effectively suppresses the structural deformation of the arch foot under external load,reducing the structural convergence.The increase in external load caused by expansion pressure is mainly concentrated in the range of the right arch waist and right side wall.In practical engineering,its influence range should be considered,so as to provide reference for disease treatment through the calculation and analysis.