Abstract: The excavation of the urban pedestrian underpass often induces the undesired deformation and even damage to the underground utilities nearby. The pipeline is idealized as the beam on the elastic soil foundation and the longitudinal bending formula of the underground pipelines is derived. The failure criterion for the flexible pipelines with rigid joint is also proposed. Assuming that the settlement trough of the pedestrian underpass has the shape of the Gaussian normal distribution, the surface and subsurface settlement prediction formula and their relationships among parameters are presented. Based on the underpass construction monitoring data, the safety analysis case history of a gas line affected by the underpass excavation is presented.

Key words: Urban Pedestrian Underpass, Underground Pipelines, Settlement Trough, Safety Analysis