Wu Xiaonan, Lu Hongfang, Wu Shijuan
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.
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.
Springerplus. 2015 Oct 31;4:659. doi: 10.1186/s40064-015-1453-1. eCollection 2015.
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.
长距离管道沿线的地质条件复杂。考虑到高程差异和地形障碍，长距离管道通常通过隧道铺设。油气管道常并排铺设以降低建设成本并减少对地质的影响。并行油气管道的布局和施工比单条管道更为复杂。为降低安全隐患，有必要对穿越隧道的油气管道进行应力分析。在本研究中，建立了穿越隧道管道的应力分析模型。基于有限元方法，利用CAESAR II软件分析了一段穿越隧道的并行油气管道的应力和位移，并从分析中得出应力和位移分布规律。对应力影响因素的研究建议如下：(1) 隧道内并行油气管道的支墩间距应为12米；(2) 倾斜管道的角度不应大于25°；(3) 在地震作用下，输油管道的应力比输气管道的应力增强更明显；(4) 采用“阶梯”式铺设可降低平均应力；(5) 可在隧道进出口处设置导向弯头以降低应力。
