Abstract:

In order to improve the construction technology of pile foundation and protection effect of the metro tunnel, the horizontal deformation and settlement displacement caused by test pile construction are monitored, and the deformation characteristics of metro tunnel induced by pile foundation construction under different clear distance and types of pile foundation are analyzed. The analytical results show that: (1) When the clear distance between pile foundation and metro tunnel is 5 m and the fullsleeve fullrotation drilling rig is used, the influence of drilling construction on horizontal displacement of the tunnel is greater than that on settlement displacement; the time and speed of the drilling rig should be paid attention to. (2) When the clear distance between pile foundation and metro tunnel is 12 m and the halfsleeve fullrotation drilling rig is used, the influence of drilling construction on tunnel settlement is greater than that on horizontal convergence displacement; the sleeve length should meet the requirement of artesian aquifer penetration. (3) When the clear distance between pile foundation and metro tunnel is 20 m, conventional drilling rigs can be used; the horizontal displacement moves away from pile foundation and then moves back; and the settlement displacement of tunnel moves downward and then becomes stable.

Key words: fullsleeve fullrotation drilling rig, metro tunnel, test pile construction, deformation monitoring