۱ اردیبهشت ۱۳۹۹
دسته:
کد : 625
Rock grouting at dam sites

عنوان : Rock grouting at dam sites

نویسندگان : Ewert, Friedrich-Karl; Hungsberg, Ulrich

از : Professional practice in earth sciences

انتشار : Springer, Year: 2018

شابک (ISBN ) : ۹۷۸-۳-۳۱۹-۶۴۰۳۶-۵,۳۳۱۹۶۴۰۳۶۴,۹۷۸-۳-۳۱۹-۶۴۰۳۵-۸

تعداد صفحات : ۲۴۰

فرمت : PDF

Description:
This book focuses on the permeability of the foundation of dams, how to determine their state and how to tighten permeable rock to achieve safe foundations for large dams. It includes theoretical fundamentals as well as lessons learned in their application in practical construction work in eminent projects. It also discusses aspects such as the permeability of the rock mass at the dam site, including the hydraulic Read more…

Introduction:

Grouting applied at dam sites today is usually carried out to consolidate the foundation (‘consolidation grouting’), to seal the contact between rock and concrete (‘contact grouting’) and to tighten the rock down to a certain depth (‘curtain grouting’). The grouting of open fissures or other natural voids is called ‘penetration grouting’, the grouting of latent discontinuities to achieve a pre-stressing of the rock is called ‘displacement grouting’, it is mostly applied in tunnelling. This book intentionally deals with penetration grouting for curtains. A comprehensive literature is available on the technology of rock grouting, mainly dealing with the procedure itself. However, ‘how to grout’ should be the second question, the first one should be ‘whether to grout, and where, and how much’. All this depends on the hydrogeological situation of the entire dam site and on the groutability. The permeability of the rock surrounding a borehole is often not identical with the permeability of a large rock mass and a permeable rock is not necessarily groutable. These complexities have received too little attention in the past although they determine both the under-seepage and the success of the grouting work and they are much more complicated than technological issues. Therefore, dealing with this first question means examining whether the rock at the dam site is permeable, whether this permeability determines the entire hydrogeological regime and whether the rock is groutable. Rock masses comprise a great variety of permanently changing conditions. This makes it difficult to recognize their permeability and groutability. In penetration grouting, the task is not simply to press grout into the rock but to fill actual water paths—quite often not the same. The first task is possible in most cases, the latter is not everywhere achieved, mainly because the given groutability is not duly considered and grouting is often carried out rather schematically instead.

 

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