摘 要

隧道施工引起的地表沉降是影响地铁安全的一个重要因素，地表沉降过大不但可能引起隧道本身坍塌失稳，而且对隧道周边的建筑物及管线产生巨大的破坏和影响。隧道开挖引起的地表沉降分为横向、纵向沉降，研究地表沉降的规律对控制地铁施工有重要的指导作用。

本文在查阅大量文献的基础上对城市平行双线隧道浅埋暗挖施工下的地表沉降进行了深入的分析，包括地铁施工的常用方法，浅埋暗挖施工时地表沉降的机理，地表沉降的横向、纵向沉降规律及各种影响因素对地表沉降的影响程度,分析了隧道几何形状、隧道上覆土质、隧道埋深、开挖方法、施工管理水平等因素对地表沉降的影响。分别采用经验法中的 peck 公式法和偏移参数法对武汉市地铁 2 号线某些浅埋暗挖区间的工程实测数据进行拟合，验证了对于平行双线地铁浅埋暗挖区间而言偏移参数法较之 peck 公式法拟合效果更好，文中选用拟合精度更高的偏移参数法对武汉市特定地质条件下的地表沉降进行比较深入的分析，由高斯曲线分布公式反推出样本区间若干断面的地表最大沉降值、沉降槽宽度、地层损失率的预测值，用概率统计的方法确定这些参数的变化范围并寻找规律，给出武汉市特定地质条件下的经验法参数建议值，为工程实际施工提供参考。

关键词：浅埋暗挖      平行双线隧道      地表沉降      沉降规律      偏移参数法    

Abstract

   The ground settlement due to metro construction is one of the most important safetyfactors.  Excessive  excavation  may make  the  metro  collapsed.  It  is  very  important  toreduce the influences of construction on surrounding environment，including buildingsand  pipelines.  Metro  excavation  can  cause  both  horizontal  and  vertical  grounddeformation. Therefore, empirical method is used in this thesis to predict the influences of construction on the ground settlement herein.

   Detailed analysis for urban parallel twolane tunnel constructed by shallow miningmethod  is  given  in  this  thesis.  Brief  introduction  about  shallow  mining  method,  themechanism  of  ground  deformation  due  to  shallow  mining  method,rules  of  metroexcavation both horizontally and vertically are made in this thesis and it also figures outthe  influence  quantity  of  various  factors  which  affect  the  ground  settlement.  In  reality,ground  deformation  depends  on  a number  of  factors,  including  hydrogeological  andgeotechnical conditions, tunnel geometry and depth, excavation methodsand the qualityof  workmanship  and  management.  Both  peck  formula  method  and  the  migrationparametric method are used in this thesis. The fitting results of ground settlement resultedfrom  the  ground  deformation  of  tunneling  are  presented  and  the  migration  parametricmethod which has higher fitting accuracy is used to reveal the rules of horizontal grounddeformation. It combines the actual situation of the project and the subway constructionstandards.  Statistical  analysis  about  the  ground  settlement  is  given  by  the  parameters,such  as  trough  width  parameter,  experience  factor, ground  loss,  the  maximum  surfacesettlement  etc.  The  range  and  rules  of  these  parameters  can  help  to  guide  the  future construction.  

   Key words：Shallow mining method    Parallel two-lane tunnel     Ground settlement   Settlement rules    Migration parametric method