小净距隧道群中夹岩水平位移规律的现场实测研究

以福建省平潭综合实验区龙兴岭隧道为工程背景,对小净距隧道群开挖过程中的现场实测数据展开细致分析,重点关注中夹岩的水平位移规律。外侧中夹岩的深度累加位移曲线呈现“V”字形,随着掌子面推进,曲线发生朝向开挖隧道侧的水平偏移,并在开挖至测孔断面后达到最大值。外侧中夹岩的时间累计位移曲线呈现“D”字形,且在隧道上方软弱地层中,发生朝向开挖隧道侧的明显水平偏移。内侧中夹岩先发生朝向先行洞侧的偏移,后回弹并逐渐趋于稳定。中夹岩变形是时空效应共同作用的结果,开挖明显影响范围一般为监测断面前后8 m。

In-situ Monitoring on the Displacement of Interlaid Rock in Neighborhood Tunnels

Based on the Longxingling Tunnel of Pingtan comprehensive experimental area in fujian province,the field monitoring data during the excavation of neighborhood tunnels were well analyzed and the horizontal displacement of the interlaid rock was focused.The depth-cumulative displacement of the interlaid rockin the outer side presents a“V”shape.The curve shifts toward the excavation side with the advancing of tunnel face,and reaches its maximum value just after the tunnel face passing through the measurement section.The time-cumulative displacement of the interlaid rockin the outer side exhibits a“D”shape.The curve is bulging toward the excavation tunnel side in the relative-soft ground above the tunnel crown.The interlaid rock in the inner side first shifts toward the pilot tunnel,and then rebounds gradually after the excavation of neighborhood tunnel.The deformation of the interlaid rock is influenced by both space and time effects,and the influence range of excavation is about 8 m before and after the monitoring section.