title: Stress analysis of parallel oil and gas steel pipelines in inclined tunnels.
abstract: Geological conditions along long distance pipelines are complex. In consideration of differences in elevation and terrain obstacles, long distance pipelines are commonly laid through tunnels. Oil and gas pipelines are often laid side by side to reduce construction costs and minimize geological impact. The layout and construction of parallel oil and gas pipelines are more complex than those of single pipelines. In order to reduce safety hazards, it is necessary to carry out stress analysis of the oil and gas pipelines that run through tunnels. In this study, a stress analysis model of pipelines running through a tunnel was developed. On the basis of the finite element method, CAESAR II software was used to analyze the stress and displacement of a section of parallel oil and gas pipelines that run through tunnels and stress and displacement distribution laws were drawn from the analyses. A study of the factors influencing stress recommended that: (1) The buttress interval of the parallel oil and gas pipelines in a tunnel should be 12 m; (2) The angle of inclined pipelines should be no greater than 25°; (3) The stress of oil pipelines enhances more obviously than that of gas pipelines under earthquake action; (4) The average stress can be reduced by adopting "ladder" laying; and (5) Guide bend can be set at the tunnel entrance and exit in order to reduce the stress.
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan China ; School of Civil Engineering and Architecture, Southwest Petroleum University, Chengdu, Sichuan China.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan China ; School of Petroleum Engineering, Southwest Petroleum University, Chengdu, Sichuan China.
authors.forename: Hongfang
authors.initials: H
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan China ; School of Petroleum Engineering, Southwest Petroleum University, Chengdu, Sichuan China.
authors.forename: Shijuan
authors.initials: S
authors.lastname: Wu
keywords: Displacement analysis; Earthquake action; Inclined tunnel; Parallel oil and gas pipelines; Stress analysis; Stress influencing factors