围岩浸水对黄土地铁隧道稳定性影响分析

为了了解黄土围岩在浸水后对隧道周围土体和衬砌结构稳定性的影响,选择西安地铁二号线南康村-方新村区间隧道工程,借助有限元分析软件对计算模型采用施工和浸水两种工况进行模拟对比,同时结合现场监测数据,对黄土地铁隧道周围土体和衬砌结构受力及变形特性进行分析研究.分析结果表明:浸水后衬砌整体下沉3 mm,地表沉降8.48 mm,...

Influence on Stability of Loess Subway Tunnel in Flooded Surrounding Rock

In order to understand the influence of flooded loess surrounding rock on the stability of the surrounding soil body and lining structure,tracking the tunnelling project in the Nankang village-Fangxin village section of Xi’an Subway Line No.2,as an example,Two operating conditions——post-construction and post flooding——were simulated in comparison,with the FM software and the stressed characteristics and deformation of the loess surrounding soil body and lining structure were studied against field monitoring data.The analysis results show as follows: After getting flooded,the lining subsides by 3 mm as a whole,earth surface subsides by 8.48 mm,both meeting the requirements of urban subway for settlement;inside the flooded zone,the maximum principal stress of surrounding rock is smaller than before getting flooded,while outside the flooded zone,the former is slightly larger than the latter;after getting flooded,the area of the surrounding rock plastic zone increases by 50%;the maximum bending moment and the maximum axial force of the flooded lining rise by 7% and 15% respecturely than before getting flooded;rockbolts loose their supporting function under compressi on after getting flooded.In a word,if heavy rain floods into the loess surrounding rock in the short term,there will be no threaton the stability of the subway tunnel.