Response of Existing Foundation to Underground Channel Tunneling Activities

The construction of underground channel beneath existing infrastructure, particularly elevated bridges, poses significant risks to structural stability. This study investigates the impact of slurry machine on existing pile foundations through 3D numerical modeling using MIDAS GTS NX. The analysis focuses on variations in Total Thrust Force (F) and conduit depth, with two Total Thrust Force (F) scenarios and two conduit positions (0.5Doc and 1.5Doc below pile tip). The results demonstrate that Total Thrust Force is a critical factor influencing the structural response of pile foundations, where increased Total Thrust Force (F) leads to higher deflection, settlement, and bending moment. Additionally, deeper conduit positioning mitigates these effects, indicating that conduit depth plays a significant role in reducing structural impact. The maximum bending moment is observed at the pile head, suggesting that this area requires special attention for structural reinforcement. Furthermore, the absence of tie beams in a statically indeterminate structure amplifies the effect of foundation movements on the superstructure.This study provides valuable insights for planning safe underground conduit construction beneath existing bridge structures and highlights the importance of optimizing tunneling parameters to minimize structural risk.