ABSTRACT
As urban transportation networks expand, the need for additional cross tunnels and transfer lines in proximity to existing infrastructure has become increasingly critical. The construction of shallow tunnel adjacent to a deeper tunnel presents significant engineering and geological challenges, primarily due to the potential interactions between the tunnels. Induced stresses can cause rock deformation, potentially compromising the structural integrity of pre-existing tunnels. The excavation process of a shallow tunnel affects stress distribution within the surrounding jointed rock mass, causes ground settlement, affecting the alignment and stability of an existing tunnel at depth, potentially leading to structural damage. This study explores the effects of stress redistribution caused by the excavation process. Tunnel excavation in disadvantageously fractured, or weak, rock mass in relation to existing infrastructure could potentially trigger rockfalls and/or collapses in tunnels at depth.
