An analysis method for the influence of tunneling on adjacent loaded pile groups with rigid elevated caps

Tunnel excavation could influence the working performance of adjacent pile foundations. How to accurately predict the tunneling-induced pile responses is becoming an important issue in urban areas. Previous methods tend to neglect the influence of working loads on the tunneling-induced pile responses. In this paper, a two-stage analysis method is proposed to study the behavior of pile groups with rigid elevated caps subjected to tunneling-induced ground movements, in which the pile-pile interaction, coupling of longitudinal and lateral deformation, and influence of working loads are considered. This method is validated by comparing the results with those from a general pile analysis program, GEPAN, centrifuge test data and field measured data. Thereafter, a series of parametric studies is carried out. The results show that the influence of working load on tunneling-induced pile responses is significant. Three different features of the pile responses will take place for different depth ratios. With the increase in soil stiffness, the tunneling-induced axial force increases linearly, whereas the bending moment increases nonlinearly. For soils with high stiffness, the maximum bending moment increases linearly with the ground loss ratio within the range of 0-5%; but for soils with low stiffness, this tendency becomes obviously nonlinear. Copyright (C) 2010 John Wiley & Sons, Ltd.