深埋隧道断层段循环进尺优化模拟研究

摘要

Based on Shitang tunnel in Cangnan county as a research obj ect,FLAC3D is used for numerical simulation of the tunnel construction process under fault conditions. Based on real verified optimization,the process of monitoring cross section of tunnel surrounding rock displacement effect is analyzed.The results show that 3 different cycle footages can ensure the excavation works fault structure to be stabile,and safe.When the footage length is less,the disturbance of the surrounding rock increased.When the fault plastic district of surrounding rock displacement and impact is greater,fault exca-vation monitoring section of the total displacement ratio has no significant difference, and the fault of excavation instability is similar.Construction date is excavated by 3 m cycling footage.%以苍南县石塘隧道为研究对象,采用FLAC3D有限差分软件,对深埋隧道断层段不同循环进尺施工过程进行数值模拟,分析隧道推进过程中的监测断面围岩变形、应力大小及塑性区分布规律,对实际工况进行验证和优化.研究结果表明:本工程3种不同循环进尺均能保证开挖断层时结构的稳定,符合施工安全要求;进尺长度的减小使得围岩扰动次数增加,对断层处围岩位移变形和塑性区分布的影响较大.而断层处开挖引起监测断面的位移占总位移的比例无明显区别,断层处开挖失稳可能性相似,施工时宜采用3m循环进尺开挖.