埋地管线在沉陷情况下的可靠性分析

Reliablity Analysis of Buried Pipeline Subjected to the Settlement

场地的不均匀沉陷是导致埋地管线破坏的重要原因之一.目前,有关埋地管线在沉陷情况下的可靠性研究甚少,为了研究埋地管线在沉陷大位移下的可靠度,运用蒙特卡罗法对埋地管线在地面沉陷位移、材料性能参数、内压等随机变量下的可靠度进行计算.同时通过对变量的敏感性分析,发现地面沉陷位移、管线的直径、厚度及管线内压的变异性对计算结果影响较大.增加地面沉陷位移和管线内压将导致管线应力的增加,降低了管线的可靠度,失效概率增大;而增大管线的直径和壁厚将导致管线应力减小,提高了管线的可靠度,失效概率减小.因此减少地面沉陷位移,降低管线内压,增大管线的直径和壁厚有助于提高埋地输油钢管的可靠度.

The uneven settlement is one of the important factors which lead to damage of buried pipeline. So far, reliability analysis of buried pipeline subjected to the settlement is little both at home and abroad. Monte-Carlo Method is used to approximate reliability of buried pipeline, considering the random variables, i.e., displacement of ground settlement, material parameters and internal pressure, and the reasonable results are obtained. The results obtained by reliability analysis show that settlement displacement, diameter and thickness of pipeline and variability of internal pressure have a paramount effect on numerical results. Furthermore, reliability of pipeline will decrease with the increase of stress due to the displacement settlement and internal pressure. In contrast, the reliability will be enhanced with the increase of diameter and thickness of pipeline. In summary, reducing the displacement of ground settlement and pressure of pipeline, increasing the pipeline diameter and thickness, can enhance the reliability of oil steel buried pipeline.