盾构隧道下穿高铁路基沉降监测与预警

Monitoring and Early Warning of Subgrade Settlement for High Speed Railway Undercrossed by Shield Tunnel

针对西安地铁一号线盾构隧道下穿徐兰(徐州—兰州)高速铁路路基工程,对不同穿越阶段轨道沉降和路基不同层位土体沉降进行了分析。结果表明:隧道右线、左线穿越后最大沉降分别为2.60、3.51 mm,隧道右线穿越后,徐兰高速铁路轨道沉降槽呈V形,沿高速铁路影响范围宽约30 m;盾构隧道右线、左线先后穿越,对施工线正上方徐兰高速铁路无砟轨道影响较大,对相邻线上方无砟轨道影响不大;隧道左线下穿后,土体竖向位移在-4.1~1.2 mm波动,并在约100 d后变形趋于稳定。根据监测结果,给出了下穿期间预警管理阈值及红色预警后的应对措施。

In view of Xuzhou-Lanzhou high speed railway subgrade project undercrossed by Xi’an Metro Line 1 shield tunnel,the tracks settlement at different stages and the soil settlement at the different layers of the subgrade were analyzed.The results show that,after undercrossed,the maximum settlements of the right and left line of the tunnel are 2.60 mm and 3.51 mm respectively.The settlement groove of Xuzhou-Lanzhou high speed railway track is V-shaped after the right line of the tunnel is crossed,and the influence area along the high speed railway is about 30 m wide.It has a significant impact on the ballastless track of Xuzhou-Lanzhou high speed railway directly above the construction line,but little impact on the ballastless track above the adjacent lines,when the right and left lines of shield tunnel cross successively.After the left line of shield tunnel crosses,the vertical displacement fluctuates between-4.1~1.2 mm,and the deformation tends to be stable after about 100 d.According to the monitoring results,the early warning management threshold during undercrossing and the countermeasures after reaching the red warning are provided.