Study on the Impact of Pipelines of Different Diameters and Materials by Tunnel Excavation

This paper used the numerical method to analyze the present conditions of the pipelines. Considered here are pipelines of three different diameters and materials to study the pipeline behavior when the nearby tunnel was excavated. During the analysis, five key factors were discussed, respectively: (1) when the tunnel was excavated, including the horizontal distance and the vertical distance between the pipeline and the tunnel; (2) the cross angle; (3) the tunnel excavating procedure; (4) the underground water table; and (5) then found the influence law of the pipelines when the tunnel was constructed. Numerical simulation results showed that these factors above had different levels of effect on the present condition of the pipelines. The horizontal distance and vertical distance between the pipeline and the tunnel are the most influential factors. We must avoid the subway and pipeline parallel during the construction because the pipeline's displacement will be very large and the impact on the underground water table cannot be neglected. Ten meters horizontal distance and 10 meters vertical distance near the concrete pipeline should not be allowed during the construction; that would result in grave consequences to the pipelines.