• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Guidelines for preliminary design of unlined pressure tunnels .
【24h】

Guidelines for preliminary design of unlined pressure tunnels .

机译：无衬砌压力隧道初步设计指南。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Unlined pressure tunnels are used to convey water to hydroelectric powerhouses. Usually each project has a forebay reservoir, an intake, a pressurized tunnel, a surface or underground powerhouse and a tailrace tunnel or channel. This thesis deals with the design of unlined pressure tunnels. These were first driven by the Norwegians in hard granitic rock masses, which would constitute the ideal material for this type of structure. However the increase in demand for electrical energy has pushed the industry to implement projects in sites with less favourable geological conditions all over the world. For each pressure tunnel, there are normally three different types of sections along its length: the unlined section, the semi-lined section and the lined section. The unlined pressure tunnel is pervious to a certain extent even if the rock is hard and non-porous and the rock mass is of good quality. Unlined tunnels are thus prone to hydraulic jacking. Semi-lined tunnels use unreinforced shotcrete and/ or concrete whereas fully lined tunnels are defined as those with a steel liner cast in concrete and completed with some annulus grouting to fill voids in the steel-concrete-rock mass system around the tunnel. This type of lining is totally impervious but is very expensive to build. Thus, unlined pressure tunnels, being the most economical, play an important role in the economics of a hydroelectric power project.;The FLAC 2D analyses show that the presence of topographic features has a great influence on the minimum stress distribution. Also, that Norwegian criterion is not adequate when the tunnel diameter is large compared to the rock cover. Finally, the presence of structural features near the tunnel, greatly change the minimum stress distribution and thus renders the Norwegian criterion inadequate in those cases.;Based on these results, a design methodology is proposed for use at the preliminary stage in the form of a factor of safety against hydraulic jacking to be used in the Norwegian criterion. Limitations on the use of the criterion are presented. The thesis presents recommendations to orient investigations and for final tunnel and liner design.;In this thesis, an extensive review of literature is conducted and most published unlined pressure tunnel design guidelines against hydraulic jacking are reviewed. The thesis places emphasis on the preliminary phase when no field measurements are available. The spatial distribution of the minimum stress required to control hydraulic jacking around unlined pressure tunnel is studied. The topographic effects, the rock cover-to-tunnel diameter ratio, the presence of geological feature are all investigated using FLAC 2D code. Minimum stress results are compared to the minimum stress given by the well-known Norwegian design criterion, and a correction factor called, Cover Alteration Ratio (CAR) is introduced. Cases where the Norwegian criterion is not adequate are identified and it is proposed to deal with these situations by adopting a larger factor of safety.
机译：无衬砌的压力隧道用于将水输送到水力发电站。通常，每个项目都有一个前湾水库，一个进水口，一个加压隧道，一个地面或地下厂房以及一条尾水隧道或通道。本文主要研究无衬砌压力隧道的设计。这些是由挪威人首先在坚硬的花岗岩岩体中驱动的，这将构成此类结构的理想材料。然而，对电能的需求的增长推动了该行业在全世界地质条件较差的地点实施项目。对于每个压力隧道，沿其长度通常有三种不同类型的部分：无衬里部分，半衬里部分和衬里部分。即使岩石坚硬无孔且岩体质量良好，无衬砌压力隧道也可以一定程度地渗透。因此，未衬砌的隧道容易发生液压顶升。半衬砌隧道使用未加固的喷射混凝土和/或混凝土，而全衬砌隧道被定义为具有衬砌在混凝土中的钢衬砌隧道，并用一些环空灌浆填充隧道周围的钢-混凝土-岩体系统中的空隙。这种衬里是完全不可渗透的，但是建造起来非常昂贵。因此，最经济的无衬砌压力隧道在水力发电项目的经济中起着重要作用。FLAC 2D分析表明，地形特征的存在对最小应力分布有很大的影响。而且，当隧道直径比岩石覆盖层大时，挪威标准还不够。最后，在隧道附近存在结构特征，极大地改变了最小应力分布，从而使挪威准则在这些情况下不充分。基于这些结果，提出了一种设计方法，可用于初期阶段。挪威标准中使用的液压顶升安全系数。提出了使用该标准的限制。本文为定向研究和最终的隧道及衬砌设计提供了建议。在本文中，对文献进行了广泛的综述，并对大多数针对液压顶进的无衬砌压力隧道设计指南进行了回顾。当没有现场测量可用时，本文将重点放在初步阶段。研究了控制无衬砌压力隧道周围液压顶升所需的最小应力的空间分布。使用FLAC 2D代码研究了地形影响，岩石覆盖层与隧道的直径比，地质特征的存在。将最小应力结果与众所周知的挪威设计标准给出的最小应力进行比较，并引入了一个称为覆盖变化率（CAR）的校正因子。确定了挪威标准不充分的情况，并建议采用更大的安全系数来应对这些情况。

著录项

  • 作者

    Rancourt, Andre J.;

  • 作者单位

    McGill University (Canada).;

  • 授予单位 McGill University (Canada).;
  • 学科 Geotechnology.;Engineering Civil.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 286 p.
  • 总页数 286
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号