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While the effects of tunnel construction on vertical loaded piled foundations have been extensively explored, the impact of side-by-side twin tunnel excavation on laterally loaded pile groups remains less understood in existing literature. This study investigates the repercussions of twin tunnel excavation at various depths on a laterally loaded (2 × 2) pile group, utilizing a combination of three-dimensional centrifuge model tests and back-analyses employing a sophisticated hypoplastic model. The test IDs CD1.5_1.5, CD2.7_2.7, and CD3.7_3.7 represent tunnelling activities near the pile shaft, pile toe, and beneath the pile toe in a side-by-side twin configuration. Twin tunnelling in test CD1.5_1.5 resulted in the most significant lateral movement of the pile cap due to reduced horizontal stress near the pile group shaft. Furthermore, twin tunnelling in test CD2.7_2.7 led to a substantial transverse tilt of 0.5 % for the pile cap, surpassing the recommended 0.2 % limit per Eurocode 7. During the second tunnelling in tests CD2.7_2.7, and CD3.7_3.7, a shift in load direction from upward to downward occurred in pile P2, potentially compromising its integrity. In test CD1.5_1.5, stress reduction near the pile shaft led to pile P1 enduring a bending moment of 1050 kNm at its midpoint, exceeding its capacity of 850 kNm. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]