隧道施工时地表沉降监测控制标准探讨

Discussion on settlement standard of ground surface during tunnelling

地表沉降是判断浅埋隧道地层稳定的一个重要指标。在分析地表沉降监测重要性和隧道埋深的关系基础上,阐述了地表沉降控制标准确定的原则;针对隧道无邻近结构物段,从地层围岩稳定、经验公式和相关规范的角度探讨地表沉降控制标准,并以武广客运专线浏阳河隧道为例子进行验证。结果表明,城市隧道变形控制标准要比山岭隧道更严格,浅埋隧道要比深埋隧道控制标准更严格;围岩越坚硬、跨度越小、边墙高度越小,则允许的位移越小,反之则越大;允许的变形控制标准主要影响因素是围岩自身条件,其次是隧道的跨度。

Ground surface settlement is an important factor to evaluate surrounding rock stability of shallow tunnel.Based on analyzing of the relation between surface settlement monitoring importance and the depth tunnel,determination principles of the settlement standard are discussed.Focusing on the section without neighboring structures,settlement standard of the ground surface is studied considering rock stability,empirical formula and relative codes.The method is applied to Liuyang River tunnel in Wuhan-Guangzhou passenger dedicated line.Results show:urban tunnel's deformation standard is lower than mountain tunnel's standard;shallow tunnel' deformation standard is lower than that deep tunnel's;the harder the rock is,the lower the deformation standard is;the smaller the tunnel span is,the lower the deformation standard is;the higher the side wall is,the lower the deformation standard is;the main influence factor is the rock's property,the next is tunnel span.