| Western China owns abundant supply of oil and gas, which could meet Eastern China’s demand for resources. The construction of long.distance pipeline must run across the collapsible Midwest loess area. With the continuous implementation of China’s develop.the.west strategy, more and more long.distance pipeline constructions will appear in the collapsible loess area. As a special soil, loess is particularly collapsible under water, which would cause a range of issues in the long.distance pipeline construction and maintenance. So far, the research of pipeline issues in collapsible region is not as sufficient as we imagined, especially in Chinese academia, quantitative evaluation of geological disasters started recently, practical application is still in the stage of exploration. In order to guarantee the safety of pipeline operation, it has important theoretical significance and practical value to establish the risk assessments and to put forward suggestions for pipeline maintenance, demolition and resettlement.On the basis of investigation and existing risk assessment of oil.gas pipeline in the collapsible loess area, we concluded the types and influencing factors of the geological pipeline disasters, and analyzed the mechanism and harmfulness of them. Beyond that, we also established fuzzy comprehensive assessment. With analytic hierarchy process (AHP), we confirmed the harmful factors. Also, on the basis of technical specifications, combined with China’s relevant laws and regulations, we refined the evaluation which is suitable to China’s national conditions. The qualitative evaluation factors take maximum membership degree method and the quantitative evaluation factors to take membership degree function method, the calculation methods of evaluation matrix are defined, and the final evaluation matrix to construct auxiliary matrix, evaluation results can be expressed quantitatively, more clear and intuitive. And according to the quantitative evaluation results, the qualitative evaluation results are divided. Finally, we used the comprehensive evaluation in the investment of ten sites of Mahuining and Shi.Ian pipeline. The evaluation results conformed to the actual situation.This paper builds the fuzzy comprehensive evaluation based on the basic principle of risk assessment technology, for objective calculating and evaluation matrix. It has both qualitative and quantitative evaluation results, in line with the engineering practice. With strong operability, it can be used for pipeline workers, which has great practical value and popularization sense. |
