以西安地铁1号线盾构隧道下穿徐兰高铁为研究背景,对盾构下穿CFG桩加固高铁路基前后的现场轨道沉降监测数据进行统计分析,并采用Plaxis-3D软件建立并行盾构隧道下穿高铁路基的精细化三维有限元模型,通过与现场实测数据对比验证数值模型的有效性.在此基础上,分析盾构隧道施工引起的轨道-路基-水泥粉煤灰碎石桩(CFG桩)-土体-盾构隧道系统的沉降传递规律,探究CFG桩的受力变形.研究结果表明,盾构施工完全通过下穿段后在地表形成50m长的沉降槽,沉降分布曲线为双驼峰;CFG桩底部在盾构隧道穿越高铁路基后变得松散,最终实际有效桩长为原长的75%;通过研究不同位置的CFG桩,确定依托工程中横断面上CFG桩出现松散的范围具体为(-12.6 m,12.6 m).
Study on Settlement Patterns of the CFG Pile-reinforced High-speed Railway Subgrade Caused by Parallel Shield Tunnelling
Focusing on the shield tunnelling of the Xi'an Metro Line 1 beneath the Xuzhou-Lanzhou High-speed Railway,this study performs a statistical analysis of the monitored track settlement data before and after the tunnel-ling.A refined three-dimensional finite element model of parallel shield tunnelling crossing under a high-speed railway subgrade is established using Plaxis-3D software.The numerical model's validity is verified through com-parison with field measurements.Based on the model,the settlement transfer mechanism of the track-subgrade-CFG pile-soil-shield tunnel system induced by shield tunnelling is analyzed,and the stress and deformation behaviors of CFG piles are investigated.Research results indicate that when the shield tunnel completely passes through the railway subgrade,a 50 m long surface settlement trough forms,with a double-peak distribution curve.The bottom of CFG piles becomes loose after shield tunnelling beneath the railway subgrade,resulting in an effective pile length of 75%of the original length.The range of loosening in CFG piles in the horizontal and longitudinal sections of this project is determined as(-12.6 m,12.6 m)by studying CFG piles at different positions.
万方数据
维普
