地面建筑荷载对下方既有隧道的影响分析

Analysis of the Influence of Ground Building Load on the Existing Tunnel Below

为了研究地面建筑施工对既有隧道的影响,以某学校拟建的实训楼为背景,运用MIDAS/GTS模拟地面建筑施工中施加不同的楼层荷载,再结合现场监控量测手段,综合分析了地面建筑荷载对既有隧道的影响。研究结果表明,地面荷载的增加引起地表沉降、围岩压力的增大基本成线性关系,当地面荷载增加至8层时,隧道拱脚处二衬压应力超出混凝土容许值,其中由地面荷载所引起的压应力占30%左右,当地面荷载增加至10层时,隧道拱顶下沉量超出规范要求,其中由地面荷载所引起的拱顶下沉量占25%左右。

In order to study the impact of ground building construction on existing tunnels,taking the proposed training building of a certain school as the background,MIDAS/GTS was used to simulate the application of different floor loads during ground building construction.Combined with on-site monitoring and measurement methods,the impact of ground building loads on existing tunnels was comprehensively analyzed.The research results indicate that the increase in ground load causes a linear relationship between surface settlement and surrounding rock pressure.When the ground load increases to the 8th floor,the compressive stress of the second lining at the tunnel arch foot exceeds the allowable value of concrete,with the compressive stress caused by ground load accounting for about 30%.When the ground load increases to the 10th floor,the settlement of the tunnel arch top exceeds the specification requirements,with the settlement of the arch top caused by ground load accounting for about 25%.