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Cracking and failure of hydroelectric engineering structures due to thermal loads.

机译：由于热负荷导致水力发电工程结构的破裂和破坏。

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摘要

Many hydraulic structures exhibit significant cracking, which allows water intrusion into or through the structures. These cracks are the result of a variety of phenomena, including thermal gradient, ice loading, restrained concrete shrinkage and cycles of freezing and thawing. Conventional repair methods generally consist of local sealing of cracks and defective construction joints by cementitious or chemical grouting. In many cases, such repair is effective only for a few years and additional measures are required. The study of the mechanism of structural failures and repair effects is very meaningful for the rehabilitation of hydraulic structures.; This thesis is devoted to the analyses of dams with cracked construction joints. Such structural failure may result from the destructive combination of harsh weather conditions and ice loads. Existing methods for transient temperature analysis of dams are first discussed and suggestions are made on the suitable choice of the initial and boundary conditions for the design of new dams and rehabilitation of cracked dams. The motion of dams with defective construction joints is analyzed as a contact problem. A highly accurate interface stress evaluation method is presented for the development of an effective algorithm of crack or joint open and close displacement analysis. The results of field measurement and theoretical analyses of ice formation, horizontal and vertical loads on structures are summarized. Practical ice loading models are established in terms of ambient temperature and other environment conditions.; The dam motion, especially the joint open-close displacement is numerically simulated. The results are calibrated through field measurements. The influence of the thermal and ice loads on the dam motion are studied. The mechanism of construction joint failure is clearly captured through the interface stress analysis results. Important conclusions are drawn for both repair work and anchor strengthening strategies.
机译：许多水工结构都显示出明显的裂缝，从而使水侵入或穿过结构。这些裂缝是多种现象的结果，包括热梯度，冰负荷，抑​​制的混凝土收缩以及冻融循环。常规的修补方法通常包括通过水泥或化学灌浆对裂缝和有缺陷的施工缝进行局部密封。在许多情况下，这种修复仅有效几年，并且需要采取其他措施。对结构破坏机理和修复效果的研究对于水工结构的修复具有十分重要的意义。本文致力于对具有裂缝施工缝的大坝进行分析。这种结构性故障可能是由于恶劣天气条件和冰荷载的破坏性组合而导致的。首先讨论了现有的大坝瞬态温度分析方法，并为新大坝的设计和裂缝大坝的修复提供了适当选择初始条件和边界条件的建议。将具有不良施工缝的大坝的运动作为接触问题进行分析。提出了一种高精度的界面应力评估方法，用于开发有效的裂纹或接头开，关位移分析算法。总结了现场测量的结果以及结冰，结构上水平和垂直载荷的理论分析。根据环境温度和其他环境条件建立实用的冰负荷模型。数值模拟了大坝运动，特别是节理的开闭位移。通过现场测量对结果进行校准。研究了热负荷和冰负荷对大坝运动的影响。通过界面应力分析结果可以清楚地捕捉到施工缝破坏的机理。对于维修工作和锚固加固策略均得出重要结论。

著录项

  • 作者

    Zhang, Pixin.;

  • 作者单位

    The University of Manitoba (Canada).;

  • 授予单位 The University of Manitoba (Canada).;
  • 学科 Engineering Mechanical.; Engineering Civil.; Energy.
  • 学位 Ph.D.
  • 年度 1999
  • 页码 204 p.
  • 总页数 204
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;建筑科学;能源与动力工程;
  • 关键词

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