黄土地区穿河管道失效风险

Failure risk analysis of river-crossing pipeline in loess area

黄土地区河流形成洪水的密度大,流速快,冲击力强,容易导致河床冲刷造成管道悬空。为了评价该地区洪水对油气管道穿河悬空段的影响,针对穿河管道悬空段的受力特点,建立了管道力学模型。在此基础上,根据信息熵理论建立了管道失效风险的计算与评价方法,并以马慧宁输油管道悬跨段为例,探讨了洪水作用下管道外径、壁厚、内压、悬跨长度及埋深5个参数的变化对管道失效风险的影响。分析结果表明:管道应变能熵随洪水流速的变化曲线能够反映管道稳定性的变化规律;管道失效风险系数对管道悬跨长度的变化最敏感,而管道内压及埋深对管道失效风险影响相对较小。基于此,建议在管道风险控制过程中降低管道的悬跨长度,从而有效降低管道的失效风险。

With large density, high flow velocity and strong impact, river flood formed in loess area may scour riverbed, making the pipeline suspended. To evaluate the effect of flood on suspended section of river-crossing oil and gas pipeline in the area, considering the mechanics of the section, a mechanical model is built. Then, calculation and evaluation methods of pipeline failure risk are established according to the information entropy theory. Taking the suspended section of Ma Hui Ning Oil Pipeline as example, the effects of flood on pipeline failure in aspect of external diameter, wall thickness, internal pressure, suspension length and buried depth are discussed. Analysis results show that the changing curve of pipeline＇s strain energy entropy with the flood flow velocity can reflect the variation of the pipeline stability; the change of suspension length is has the most effects on pipeline failure risk coefficient, and the pipeline＇s internal pressure and buried depth have less effects on the risk. The pipeline＇s suspension length should be reduced in risk control to effectively reduce the failure risk.