明暗挖结合施工地铁车站地表沉降研究

摘要

Relying on a semi-open-cut subway station engineering of Dalian Metro, a large open-cut excavation and a PBA subway station which has a large section had be simulated. The excavation and support process were established into 3D model, by using FEM software ADINA. By compared the surface settlement where interrelated by the different construct steps with measure data, the paper shows that the maximum soil settlement appear in the concrete diaphragm wall back and go down away from the excavation by vertical direction. In the direction parallel to the pit, surface settlement curve shaped like a funnel. The surface subsidence rule changes significantly when the Drift-PBA method construction was completed: the surface settling curve assumes funnel shape, but contrasted with the revised Peck formula curve which based on the measured data shows that the both are similar in width of the settlement trough.%依托大连地铁一号线某明暗挖车站工程实例，通过应用大型通用有限元数值分析软件ADINA建立三维模型，模拟车站明挖基坑及大断面洞桩法暗挖开挖及支护过程，研究不同开挖步序后基坑开挖与暗挖施工相互影响部位地表沉降规律，同时结合实测监控量测数据对比总结。研究结果表明，地铁车站无内撑深基坑开挖后，垂直于基坑方向连续墙背后土体地表沉降最大，向远离基坑位置逐渐减小，平行于基坑边呈漏斗状沉降规律；大断面洞桩法暗挖施工后地表沉降显著变化，地表沉降曲线呈漏斗状变化规律，但与实测数据经修正Peck公式拟合后对比发现，两者沉降槽宽度基本一致。