下伏煤层对既有重载铁路隧道安全性的影响

Impact of Underlying Coal Seams on the Safety of Existing Heavy Haul Railway Tunnel

为研究重载列车振动荷载作用下隧底下伏煤层对隧道的影响,结合现场监测结果梳理隧道病害类型及原因,通过数值模拟分析隧底结构与下伏煤层的动力响应,提出病害处治措施。结果表明:隧底病害主要为基底围岩不密实、空洞引起的不均匀沉降;产生病害的原因为列车振动荷载作用下节理裂隙发育的软弱煤层承载力降低;仰拱中心最小安全系数不满足规范要求,在煤层应力状态持续恶化的情况下结构可能发生破坏。结合工程经验,采取打设锁脚锚管、基底注浆处治措施,效果良好。

To study the influence of underlying coal seams on tunnel structures in the action of heavy haul train vibration loads,the types and causes of tunnel diseases were sorted out based on field monitoring results.Numerical simulation was employed to analyze the dynamic response of the tunnel bottom structure and underlying coal seams,meanwhile,disease treatment measures were proposed.The results show that,the main diseases at the tunnel bottom are caused by the insufficient compaction of the foundation surrounding rocks and uneven settlement caused by voids.The reason for the occurrence of diseases is the decrease of weak coal seams bearing capacity due to the development of joint fissures under the action of train vibration loads.Through calculations,it was found that the minimum safety factor at the crown center didn’t meet the specification requirements,and the structure might be damaged under the continuous deterioration of the stress state of the coal seams.Based on engineering experience,treatment measures such as installing locking anchor pipes and foundation grouting were implemented,and the effect was satisfactory.