穿越活断层铰链式衬砌隧道减震措施动力响应研究

鉴于穿越地震活动带逆断层的铁路山岭隧道易受逆断层滑动的影响,且目前铁路隧道穿越多条活动性断层可供借鉴经验较少的现状。文章采用数值分析方法,对活动逆断层错动下的铰链式衬砌隧道在地震荷载作用下围岩加固方式、超挖设计结构的动力响应进行对比分析。结果表明逆断层错动时,对浅部地层变形的影响范围大于深部,但最大附加变形出现在深部断层面附近,且错距越大其最大附加变形值越大,断层活动对隧道结构安全影响较为显著。注浆加固并不改变衬砌在地震中的震动频谱特性,宜采用施作单层衬砌预留修复空间的设计方案。对于是否超挖设计的两种工况下,衬砌位移变化规律一致,衬砌的震动频谱特性一致。经过监控量测发现支护压应力在埋设2个月左右后趋于稳定。所得结论可为今后类似工程结构设计与施工提供参考。

Dynamic response of damping measures for hinged lining tunnels through active faults

Railway mountain tunnels passing through the reverse fault in seismic active zone are easily affected by the reverse fault slip, and at present, relevant research experience is not much. In this paper, the numerical analysis method was used to analyze the dynamic response of hinged lining tunnels under seismic load and active fault movement. The results showed that the influence of reverse fault movement on the deformation of shallow strata is greater than that of deep strata, but the maximum additional deformation appears near the deep fault plane. The larger the dislocation distance is, the greater the maximum additional deformation value is. The fault activity has a significant impact on the safety of tunnel structure, and grouting reinforcement can not change the vibration spectrum characteristics of lining during earthquake, so the design scheme of reserved repair space for single-layer lining should be adopted. Under the two working conditions of over-excavation design, the displacement variation law and vibration spectrum characteristics of lining are consistent. Through monitoring and measurement, it is found that the compressive stress of the support tends to be stable after about 2 months. The conclusions can provide a reference for the structural design and construction of similar projects in future.