在地铁隧道施工过程中，不可避免地对岩土体产生扰动，引起的土层变形可能影响地面建筑物和既有管线设施，变形达到一定程度时将影响到地面建筑物的安全和地下管线的正常使用。因此隧道施工引起的地层移动与变形，尤其是在地面建筑设施和地下管线密集的城市中施工所造成的影响及其控制途径，一直是人们关注的课题。为了有效地预防和减少隧道施工所引起的地表沉降变形及其对周围环境造成的损害，对地铁隧道工程在施工过程中进行监测具有重要的意义。 本文在深入研究城市地铁施工沉降监测相关技术的基础上，提出了Web GIS技术在地铁施工沉降监测中的应用方案。本系统结合ArcGIS Server、C#.NET、Silerlight以及SQL Server2005等软件平台，以西安地铁施工为例，设计并开发了B/S结构的基于WebGIS的沉降监测系统，初步实现了客户在浏览器端对电子地图的放大，缩小，漫游，导航，图形和属性信息互查询，以及沉降预警和沉降曲线功能，使得大量的图形信息和表信息得到了直观的表达，并为施工沉降监测实施的做出预警，反应监测点的实时沉降情况，达到了预期的预警和辅助决策的效果。

In the construction of subway tunnel, it is inevitable to producing rock and soil ‘s disturbance, which may affect the deformation of soil caused by buildings and facilities of existing pipelines, when deformation reach a certain degree,the ground will affect the safety of buildings and underground pipelines’ normal using. Therefore the movement of ground caused by tunnel’s construction and deformation, especially in a compact city and control the impact of means, has been the subject of concern. In order to effectively prevent and reduce the tunnel construction and surface subsidence caused by the deformation and damage the surrounding environment, to monitoring the processing the construction of the subway tunnel of great significance. This article depthly study related to subway construction settlement monitoring technology based on Web GIS technology in the proposed settlement of metro construction monitoring program. This system combines ArcGIS Server, C #,. NET, Silerlight and SQL Server2005 and other software platforms, Xi'an subway construction, for example, designed and developed the B / S structure of the settlement monitoring system based on WebGIS, the initial realization of the client browser for Electronic map zoom, roam, navigation, graphic and attribute information each query, and settlement functions settlement curve warning and make a lot of graphic information and tables information is an intuitive expression, and to make the construction settlement monitoring the implementation of early warning , The reaction in real time settlement monitoring points, to achieve the desired effect of early warning and decision support.