隔离桩桩径对基坑开挖引起既有地铁隧道位移的影响

Influence of Isolation Pile Diameter on Existing Metro Tunnel Displacement Caused by Excavation of Foundation Pit

以杭州市一深基坑工程为背景,采用ABAQUS有限元软件建立三维数值模型,分析隔离桩半径对既有地铁隧道位移的影响。研究结果表明:基坑开挖最终引起了隧道衬砌竖向位移约4 mm,水平位移约1 mm,与实测值相吻合;隧道衬砌位移最大值位于衬砌拱底,最小值位于衬砌拱顶,衬砌变形整体呈沉降的趋势;靠近基坑一侧隧道衬砌总位移比另一侧略大;隔离桩的半径越大,基坑开挖对既有地铁隧道的影响越小。

The excavation of a deep foundation pit in Hangzhou is the engineering background. A three-dimensional numerical model is established using ABAQUS,a finite element software. The influence ofisolation pile＇s diameter on existing metro tunnel displacement is analyzed. The results showthat,due to excavation of the foundation pit,the vertical displacement of the ultimate tunnel lining is about 4 mm and the horizontal displacement is about 1 mm. The numerical simulation results are in good agreement with the measured values. The maximum displacement of the tunnel lining is located at the bottom of the arch and the minimum value is located at the vault. The lining displacement tend to be down as a whole. The displacement of the tunnel lining side near the foundation pit is larger than that of the other side. The greater the diameter ofisolation pile is,the less the influence of the excavation of the foundation pit on existing metro tunnel is.