埋地油气管道沿线土壤腐蚀性可拓评价研究

油气管道长期埋设在土壤环境中会受到各种侵蚀介质的腐蚀并引发泄漏、火灾、爆炸等事故。针对土壤腐蚀因素复杂多变的特点，建立基于物元、可拓集合和关联函数的埋地油气管道沿线土壤腐蚀性评价模型；选取土壤电阻率、自然电位、氧化还原电位、pH值、含水率、Cl-含量、SO42-含量7个评价指标，将土壤对油气管道腐蚀的严重程度划分为低、较低、中、强和较强5个等级；采用客观赋权的变异系数法（CV法）来确定土壤腐蚀性评价指标的权重，避免了以往评价方法的主观性，进一步提高模型的精度和效率。以某埋地天然气管道5个管段土壤为例，可拓评价结果表明4#土壤的腐蚀性较强，其他土壤腐蚀性中等，这与外腐蚀检测结果吻合，证明所想出的模型简便、高效、精确，具有很好的科学性和工程应用性。

Research on extension evaluation of soil corrosion along buried oil and gas pipeline

the oil and gas pipelines buried in the soil environment over a long period of time will be corroded by various erosive medium, which may cause the accidents such as leakage, fire and explosion. Aiming at the characteristics of complexity and variability about the soil corrosion factors, through using the extension theory, an evaluation model of soil corrosion along buried oil and gas pipeline was established based on matter-element, extension set and correlation function. Seven evaluation indexes were selected, including soil resistivity, spontaneous potential, oxidation reduction potential, pH value, moisture content, Cl- content and SO42- content, and the severity degree of soil corrosion on oil and gas pipeline was divided into five grades from low to high, including low, relatively low, medium, relatively high and high. The coefficient of variation (CV) method with objective weight was applied to determine the weight of evaluation indexes about soil corrosion, which can avoid the subjectivity of former evaluation methods and improve the accuracy and efficiency of model. The soil corrosion of five pipeline sections on a certain buried gas pipeline was evaluated by using the model. It showed that the corrosion grade of 4# soil was relatively high, while the corrosion grades of others were all medium, and the overall corrosion of the soil along the pipeline was high. The evaluation results was in agreement with the detecting results of external corrosion, which proved that the evaluation model of soil corrosion established by combining extension theory with coefficient of variation method is simple, effective and accurate, and it has good scientificalness and engineering practicability, being a benefit tool to evaluate the soil corrosion along the buried oil and gas pipelines.