【作者】 黄蓉；

【导师】 彭世尼；

【作者基本信息】 重庆大学 ， 供热、供燃气、通风及空调工程， 2008， 硕士

【摘要】 随着我国现代化进程的不断加快,人民生活水平的提高,以及全球环境问题的日益突出,节能减排压力越来越大,天然气的需求呈爆炸式增长,快速地推动了城市燃气输气管网的建设。城市燃气输配系统通常由钢制管道埋地建设而成,因而,钢制埋地钢制管道的腐蚀与防护便成了急待解决的问题。作为钢制管道腐蚀的重要因素之一——土壤腐蚀也一直被国内外研究者所关注。但是至今仍没有一个大家公认的,比较切合实际的土壤腐蚀性评价方法。本文在总结和比较了前人针对埋地钢制管道土壤腐蚀性评价研究方法的基础上,采用神经网络法建立了土壤腐蚀性评价模型,该模型具有2个重要特点:一是简化了样本检测参数。从训练样本的来源上,不需要测试大量的土壤理化性质参数,而是需要通过综合影响管道土壤腐蚀的各主要因素土壤电阻率、氧化还原电位、含盐量、含水量、PH值)的单项指标,就可以建立新的多项综合指标来建立模型;其二是增加了训练样本。从训练样本的数量上,为了提高模型的鲁棒性和识别的准确性,对样本进行了扩充,在每级标准之间随机生成40组训练样本。本文在新的理论基础上,将建立的BP和RBF两种网络运用到廊坊市燃气管道的腐蚀调查中,应用结果表明,RBF网络在对新样本的预测精度方面优于BP网络。该方法可用于现场管道的土壤腐蚀评价,同时也可以为管道的及时维修和更换提供科学的依据。更多还原

【Abstract】 With the accelerating pace of modernization of our country, the improvement of people’s living standards and the increasingly outstanding global environmental problems, the pressure of energy-saving and environmental protection is more and more big. The explosive growth of natural gas demand is promoting the construction of urban gas network rapidly. Urban gas transmission and distribution system is usually constructed by buried steel pipe, so the corrosion and protection of steel pipeline has become problems to be solved. As one of the important factors—soil erosion is always concerned by researchers at home and abroad. But up to now, we havn’t find a recognized and more realistic evaluation of soil corrosion.Based on the evaluation method of pre-scholars, this paper established the model of soil corrosion evaluation by ANN. This model has two important features:the first, it simplifies the testing samples parameters. It doesn’t need a lot of soil physical and chemical properties, but only need combine some important individual index of soil pipe corrosion(soil resistivity, oxidation—reduction potential, salinity, water content, PH), we can create a new integrated model. The second, it increases the number of training samples. In order to improve the robustness of the model and the accuracy of the identification, the samples were expanded by generating 40 data sets randomly in each class standards.On the basis of new theory, this paper used BP and RBF network into corrosion survey of gas pipelines in Langfang. The application results show that the RBF network is better than BP network in the forecast accuracy to new samples. This method not only can be used for on-site assessment of soil corrosion of urban gas pipeline, but also provide a scientific basis for urban gas pipelines’maintenance and timely replacement.更多还原