ISSN:
1434-453X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Architecture, Civil Engineering, Surveying
,
Geosciences
Notes:
Summary Construction of four single track railway tunnels through sedimentary rocks in central British Columbia, Canada, provided an excellent opportunity to compare various rock mass classification systems and to evaluate their applicability to the local geology. The tunnels were excavated by conventional drilling and blasting techniques and supported primarily with rock bolts and shotcrete, and with steel sets in some sections. After a brief project description including tunnel construction techniques, local geology and groundwater conditions, the data collection and filed mapping procedure is reviewed. Four rock mass classification systems (RQD, RSR, RMR, Q) for empirical tunnel design are reviewed and relevant factors for the data interpretation are discussed. In comparing and evaluating the performance of these classification systems three aspects received special attention. The tunnel support predicted by the various systems was compared to the support installed, a unique correlation between the two most useful and most frequently applied classifications, theRMR andQ systems, was established and assessed, and finally, the non-support limit and size effect were evaluated. It is concluded that theQ-system best predicted the required tunnel support and that theRMR was only adequate after adjustment for the influence of opening size. Correction equations for opening size effects are presented for theRMR system. TheRSR andRQD systems are not recommended for empirical tunnel design.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01039996
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