双层车站零距离下穿既有车站变形控制技术

Control Technology of Zero-distance Under-passing Existing Station in New Two Layers Station

大中城市地铁已由点线状发展成网状,常会出现既有地铁车站密贴增建形成换乘车站的情况。为了保证既有地铁车站的正常使用,开展新建地铁车站密贴下穿既有地铁车站变形控制研究。依托北京地铁6号线苹果园站零距离下穿既有地铁1号线苹果园站工程,结合具体施工方案,采用数值方法研究两层三跨地铁车站密贴下穿既有结构变形控制技术,探究注浆抬升、丝杠支顶、高压回填注浆工程措施对既有结构变形控制所起作用,分析丝杠的力学特性并优化其直径。通过现场测试与数值分析对比分析,验证以上工程措施的控制效果。研究表明:注浆抬升作用对既有结构变形控制效果更加明显;丝杠直径对既有结构沉降影响不大,选取50 mm可以充分发挥丝杠材料性能;注浆抬升、丝杠支顶、高压回填注浆3个综合措施控制了既有地铁车站变形。

Metro in large and medium-sized cities has developed from point-line to net,and existing subway stations often become transfer stations.The deformation control technology for the existing subway station that a new subway station underneath was studied so as to ensure the normal use of existing subway stations.Based on the Pingguoyuan station of Beijing Metro Line 6 west extension project,the deformation control technology of two-story three-span subway station underneath existing structure was studied by numerical method.Then the effect of engineering measures,including grouting lifting,screw support top and high pressure backfill grouting were explored on existing structures deformation.Furthermore,the screw diameter was optimized by analyzing the mechanical properties of screw.The control effect of the above engineering measures was verified by field test and numerical analysis.The results shows as follows.The grouting uplift effect has more obvious control effect on the deformation of existing structures.Screw diameter has little effect on the settlement of the existing structure,50 mm can give full play to the screw material performance.The deformation of the existing subway station is controlled by three comprehensive measures,including grouting uplift,screw support and high-pressure backfill grouting.