The Impact of Dynamic Mechanical Vibration on Shallow Road Caps: A Case Study of Micro‑tunneling Pit Failure in the Gulf

This study investigates a shallow road cap failure that occurred during the excavation of a 15‑meter‑deep micro‑tunneling sending pit in Doha, Qatar. Although the underlying Ghaly Formation exhibited strong static stability, dynamic mechanical vibrations generated by the micro‑tunneling machine propagated upward and weakened the unconsolidated sub‑base beneath a 2‑meter pavement structure. The resulting loss of stiffness and particle rearrangement triggered localized settlement and collapse adjacent to the pit. The study highlights the discrepancy between deep static stability and shallow dynamic vulnerability in urban infrastructure projects across the Gulf region. Findings emphasize the need for vibration modeling, pre‑grouting, and real‑time monitoring to prevent similar failures in trenchless construction environments.<br><br><br>