Insights from 3D numerical simulations on the impact of tunnelling on vertical and battered pile groups under lateral loading

This study presents the impact of tunnelling on a battered and vertical pile groups when subjected to lateral loads. A comprehensive investigation was undertaken to examine the effects of varying the tunnel depth in relation to the length of the pile group, as well as the direction of the lateral load (i.e., towards and away from the tunnel). A sophisticated hypoplastic model, which has the ability to accurately represent the small strains stiffness was used to capture clay behaviour. As compared to the battered pile group, the vertical pile group exhibited the largest pile cap lateral displacement due to tunnelling adjacent to pile shaft. The tunnel below the battered pile group toe exhibited the most significant pile cap lateral displacement and tilting of the pile group. The stress release caused by tunnelling in the vicinity of the pile shaft induced the largest bending moment in both battered and vertical pile groups, regardless of direction of the applied lateral load. The pile cap experiences linearly increasing lateral movement with tunnel volume loss. Moreover, the lateral movement and tilting are greater in the presence of lateral loads compared to vertical loads on the battered pile group.