Reliability Analysis of Underground Pipelines Subject to Disturbance of Shield Tunnel Excavation

Tunnel excavation disturbs surrounding soil, cause deformation and displacement of the soil, and can result in a change of loads and constraints exerted on the pipelines in the vicinity of the tunnel. The internal forces of the pipelines will accordingly redistribute. Therefore, the safety level of the pipelines will change, mostly to decrease, In this paper, two types of pipelines, rigid pipeline and flexible one, are discussed. Then formulae which link the maximum ground subsidence with the deformation of a pipeline are derived under shield tunnel excavation. In consideration of the uncertainties in the parameters of the formulae, a probabilistic analysis on the safety of pipeline is conducted, according to the control criterion of both rigid and flexible pipelines. Finally, a case study is conducted to demonstrate the applicability of this method. This paper presents a convenient method to determine the safety of underground pipeline through the measurement of ground subsidence occurring during tunnel excavation.