Development of tunneling influence zones for adjacent pile foundations by numerical analyses

In this study, three-dimensional elasto-plastic numerical analyses are conducted to investigate the influences of tunnel excavation on existing loaded piles. The effects of parameters on pile responses to be used as criteria for suggesting the influence zones can be captured from the analysis method. A large number of analyses are then carried out to generate the artificial data of pile responses from tunneling for establishing the influence zones. Deep and shallow tunneling are separately considered with their influence zones are suggested from the normalized pile settlement and the induced pile bending moment, respectively. The two zones are then combined. Based on the ground condition, geometries of the pile and the tunnel, tunnel construction method, and evaluated criteria considered in this study, the unique significant zones of influence for various conditions can be identified.

► Normalized pile settlement and bending moment are numerically evaluated as criteria for suggesting influence zones.
► We generated data of pile response from a large number of analyses.
► Unique significant zones of influence for various conditions can be identified.
► Influence zone within critical line is deeper and wider than that of conventional shear surface.
► Inclination of the zone is 60° irrespective to soil properties.