关键词: 黄土地区, 管道工程, 环境风险分析与评价

Abstract: By analyzing and evaluating the environmental risk of Shaanxi-Ganshu natural gas pipeline engineering, this paper studied on the risk evaluation of long oil and gas transported pipeline engineering. The evaluating order was that of risk discrimination→risk analysis→risk evaluation →risk control and its countermeasures. The evaluating methods included analogical analysis, qualitative and quantitative analysis and accident tree analysis. Shaanxi-Ganshu natural gas transported pipeline was 35369 km long and went through Mu Us sandy land region, loess flat highland, loess weir and mound region and valley region. The main environmental risk factors along the pipeline included water loss and soil erosion, loess sink by landslide, collapse, flood, debris flow, wind erosion and desertification, earthquake and human factors etc.. The accident rate of the pipeline estimated by analogical analysis was about 0792 times/(103 km·a). For each division of the pipeline, the environmental risk index (R) and the order of risk probability have been given out from accident tree function (T) calculating. The carrying out of measures must be based on the principle of reduction, diversion, replacement and avoiding accident occurrence. The studying results of the example have provided a general evaluating orders and methods for risk evaluation of transporting oil and gas engineering in Loess Plateau. In details, long oil and gas transported pipeline should go through loess flat highland region and from loess weir and mound region; in wind erosion and shifting eaolian sand region of northern Loess Plateau, the key to make sure the pipeline run normally was to strengthen ecological protection and reduce the human being's irrational productive activity; natural hazards as the indefinite risk factors should be on guard according to the historical data and the risk evaluating results; the accident rate induced by external influence (human factors) and mechanical trouble took up 472%-708% of total accident rate, so it is important to pay more attention to external impact and mechanical quality problems in the processes of constructing oil and gas transported pipeline.

Key words: Loess region, Pipeline engineering, Environmental risk analysis and evaluation