Although intensive research of the influence of ground motion duration on structural cumulative damage has been carried out, the influence of dynamic responses in underground tunnels remains a heated debate. This study attempts to highlight the importance of the ground motion duration effect on hydraulic tunnels subjected to deep-focus earthquakes. In the study, a set of 18 recorded accelerograms with a wide-range of durations were employed. A spectrally equivalent method serves to distinguish the effect of duration from other ground motion features, and then the seismic input model was simulated using SV-wave excitation based on a viscous-spring boundary, which was verified by the time-domain waves analysis method. The nonlinear analysis results demonstrate that the risk of collapse of the hydraulic tunnel is higher under long-duration ground motion than that of short-duration ground motion of the same seismic intensity. In a low intensity earthquake, the ground motion duration has little effect on the damage energy consumption of a hydraulic tunnel lining, but in a high intensity earthquake, dissipation of the damage energy and damage index of concrete shows a nonlinear growth trend accompanied by the increase of ground motion duration, which has a great influence on the deformation and stress of hydraulic tunnels, and correlation analysis shows that the correlation coefficient is greater than 0.8. Therefore, the duration of ground motion should be taken into consideration except for its intensity and frequency content in the design of hydraulic tunnel, and evaluation of seismic risk.
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1.
中国侏罗系煤成油若干问题 总被引：7，自引：0，他引：7
在阐述了煤成油的概念，总结和评述了煤生油显微组分，生油门限，生油范围和生油高峰等问题后，本文通过吐哈等盆地侏罗系煤生油显微组分组成特征，可溶有机质演化，成熟度和有机质丰度，油源及原油成熟度对比；含煤岩系中煤层和泥岩的厚度及总量和煤及泥岩最高沥青和总烃转化率的对比； 其族组成和煤成原油的族组成特征的对比，提出了中国侏罗系煤成油盆地中泥岩比煤层对煤成油田形成有大的贡献看法。 相似文献
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基于MapObjects和ArcIMS的耕地后备资源GIS 总被引：1，自引：0，他引：1
研究MapObjects和ArcIMS在耕地后备资源信息化建设中的应用,在此基础上设计和实现系统结构,并在山东省进行实践应用,取得了良好的效果。实践证明,该系统能方便地显示地图和各种信息查询,可以推广到全国使用。 相似文献
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The problem of dam safety is one of the most important research topics of water conservancy projects, and many researchers pay much attention to study the risk of earth dam overtopping. This paper synthesizes in the definition of risk the probabilities of dam failure and the corresponding losses, including the probability estimation, losses evaluation and criteria exploring risk approaches. Then, a comprehensive risk assessment system of dam flood overtopping is established, which is widely applicable. Gate failure, randomness of flood, initial water level and time-varying effects are incorporated in the failure probability model. Many complex factors are simplified in losses estimation. In addition, thresholds of various types of losses are proposed and are adapted to the national conditions. The methodology is applied to the Lianghekou hydropower station in China to illustrate the assessment process of flood overtopping risk and to evaluate its safe loophole with a view to the failure of spillway gates. Monte Carlo simulation and JC method programs are adopted to solve the model based on MATLAB tools and DELPHI. The results show that the losses pose significant impact on the risk assessment and should be considered in the assessment of risk. Probability calculation and loss estimation could be well combined with standards, providing a basis for risk management and decision-making. 相似文献
4.
在原煤炭工业部组织的4次全国煤炭资源预测和评价中,其中3次分别运用了槽-台学说、地质力学理论和板块构造理论。简要评述了前3次煤田预测成果。在此基础上,通过分析第4次煤田预测以来的板块构造理论和煤田地质研究进展,以及对2006年6月开始的煤炭资源潜力评价,建议在总结阶段,应在不同板块构造体制下,根据含煤原型盆地恢复、大地构造单元性质与盆地构造演化,对煤炭聚积、煤化作用的控制和影响进行研究,并提出了建立板块构造理论指导下的中国煤炭资源潜力评价的工作思路与技术路线。 相似文献
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煤造石油与煤成油理论关系研究进展综述 总被引：1，自引：0，他引：1
综述了煤造石油的研究进展。煤加氢液化研究结果表明挥发分、Ｈ与Ｃ比值、煤级、催化剂是影响煤炭液化的重要因素;对煤造石油与石油玩机成因说、煤造石油与煤一理论之间的联系进行了评述,现代含煤岩系煤成油研究得出的结论与煤造石油实践得出的结果近似一致,一些大油田分布带与大构造活动区带近于一致,由此使人们得出了类似于Ｆ－Ｔ法合成的石油无机成因理论。 相似文献
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穿越含水疏松砂岩层的深埋输水隧洞围岩稳定和支护控制问题是长距离输水生命线工程中的难点,其施工开挖和支护控制方法目前尚不完善。结合某深埋输水工程疏松砂岩层的支护工程实践,分析了疏松砂岩层冻结施工过程及解冻后土体力学性质的演化以及围岩支护联合受力机制,采用有限元法揭示了冻融过程下围岩的变形规律及支护受力演化特征,并提出疏松砂岩层冻结施工及分步联合支护的设计理念和支护方案。研究结果表明,采用分步联合支护方法能够得到较理想的支护效果,冻结施工段进行支护结构刚度设计和数值验证时应考虑冻融过程对围岩的扰动弱化,让各种支护手段在时间和空间上实现有效结合,使围岩和支护结构紧密结合,形成受力机制明确的联合受力体。 相似文献
9.
高文泰先生的研究领域涉及煤田地质学和构造地质学的一系列重大问题,他承担了第一次全国煤田预测的学术指导工作,为新中国煤炭资源勘查和煤炭地质教育事业的发展以及中国煤田地质学理论体系的建立奠定了坚实的基础。高先生积极倡导将板块构造理论应用于煤田地质研究领域,强调板块构造格局对中国煤田分布的控制作用,这从战略上指出了找煤方向;重视构造地质与煤田地质之间的紧密联系,对中国煤变质特征和有关煤岩问题进行了有益的探讨,强调构造格局和构造作用对煤变质的影响;注重加强隐伏煤田构造研究,提出隐伏煤田构造研究的思路和技术方法体系,并在找煤实践中取得良好效果。高先生重视新技术、新理论、新方法在煤田构造研究学中的应用,积极推动学科发展。 相似文献
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通过华北板块南缘北东地区的弧形构造特征、形成时代和瓦斯分布特征的研究,得出如下结论:1徐宿弧形构造限于丰沛断裂与蚌埠隆起北缘的五河断裂间,为形成于早三叠世后、晚侏罗世前的推覆构造;其形成与动力来源可能是扬子板块沿着郯庐断裂带向西或北西方向俯冲于华北板块之下的碰撞拼贴作用。2徐宿弧形推覆构造中和面外侧引张、内侧挤压的构造应力场是导致位于弧形内侧的宿东向斜内煤矿瓦斯富集、外侧闸河向斜瓦斯含量相对较少的主因之一;煤矿区内岩浆岩体(脉)的侵入改变了这种本应规律的瓦斯分布图案。岩浆活动和构造作用共同构建了华北板块南缘北东地区的构造和瓦斯分布图案。 相似文献
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