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埋地燃气管道综合检验检测技术研究 总被引:9,自引:5,他引:9
随着技术的进步以及国家能源政策的调整,埋地管道的安全运行日益得到了管道使用单位和政府相关职能部门的重视。综述了目前国内外常用的埋地钢质管道检验检测方法的原理及其优缺点,并结合作者的研究成果,提出了埋地管道综合检验检测技术组合方法。 相似文献
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This paper presents a simplified method for the reliability- and the integrity-based optimal design of engineering systems and its application to offshore mooring systems. The design of structural systems is transitioning from the conventional methods, which are based on factors of safety, to more advanced methods, which require calculation of the failure probability of the designed system for each project. Using factors of safety to account for the uncertainties in the capacity (strength) or demands can lead to systems with different reliabilities. This is because the number and arrangement of components in each system and the correlation of their responses could be different, which could affect the system reliability. The generic factors of safety that are specified at the component level do not account for such differences. Still, using factors of safety, as a measure of system safety, is preferred by many engineers because of the simplicity in their application. The aim of this paper is to provide a simplified method for design of engineering systems that directly involves the system annual failure probability as a measure of system safety, concerning system strength limit state. In this method, using results of conventional deterministic analysis, the optimality factors for an integrity-based optimal design are used instead of generic safety factors to assure the system safety. The optimality factors, which estimate the necessary change in average component capacities, are computed especially for each component and a target system annual probability of system failure using regression models that estimate the effect of short and long term extreme events on structural response. Because in practice, it is convenient to use the return period as a measure to quantify the likelihood of extreme events, the regression model in this paper is a relationship between the component demands and the annual probability density function corresponding to every return period. This method accounts for the uncertainties in the environmental loads and structural capacities, and identifies the target mean capacity of each component for maximizing its integrity and meeting the reliability requirement. In addition, because various failure modes in a structural system can lead to different consequences (including damage costs), a method is introduced to compute optimality factors for designated failure modes. By calculating the probability of system failure, this method can be used for risk-based decision-making that considers the failure costs and consequences. The proposed method can also be used on existing structures to identify the riskiest components as part of inspection and improvement planning. The proposed method is discussed and illustrated considering offshore mooring systems. However, the method is general and applicable also to other engineering systems. In the case study of this paper, the method is first used to quantify the reliability of a mooring system, then this design is revised to meet the DNV recommended annual probability of failure and for maximizing system integrity as well as for a designated failure mode in which the anchor chains are the first components to fail in the system. 相似文献
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反射波法和机械阻抗法作为基桩完整性检测的基本方法。在基桩检测中,两种方法对比使用,可取长补短,有效排除干扰,能够准确、真实地反映基桩质量。 相似文献
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尤晓露 《辽宁省交通高等专科学校学报》2012,14(3):34-36
诚信的信息披露是资本市场的基石,是确保建立公平、公开、公正资本市场的基本前提。我国证券市场由于发展迅速,在信息披露方面存在很多不完善的地方,从而造成财务舞弊事件时常发生,引起投资人及社会公众对上市公司的信任危机,严重影响了资本市场的发展。因此,建立完善的诚信信息披露机制是保证资本市场健康发展的有效途径。 相似文献
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