Progressive deformation of the large natural rock slope at British Columbia Hydro's
Wahleach hydroelectric project is an ongoing phenomenon. Slope movements have caused
significant operational problems in the original power tunnels located within portions of the
deforming slope, and pose a recognized hazard to property and facilities located at the base
of the slope.
Developing a more comprehensive understanding of the rock slope deformation mechanics
has been fundamental in evaluating the potential risk to facilities located at the base of the
slope. This has been achieved through an extensive investigation and monitoring program,
and supported by detailed numerical modelling studies presented in this report.
Numerical modelling with the finite difference FLAC computer code has utilized the
extensive slope monitoring history developed between 1989 and 1994 to evaluate the model
response. This has allowed the model to be used to evaluate the possible failure modes in
the slope and to investigate the effects of future loading conditions such as earthquakes and
extreme precipitation events, in addition to the potential long term evolution of the slope
movement process.
Application of the FLAC code enabled a representative simulation of observed slope
conditions to be made. Modelling results yielded excellent comparison with slope
instrumentation data, developing confidence in the modelling capabilities to carry out
predictive analyses of potential future loading conditions. The modelling indicated the
importance of transient groundwater flow to the deformation process in the upper 40 to 70
metres of the rock mass.
B.C. Hydro recognized the potentially critical impact of adverse slope movement on the
collection of hydroelectric, transportation and communication facilities located at the base of
the Wahleach slope. Comprehensive investigative work, undertaken following the rupture
of the steel lining of the power conduit, concluded that the nature of the slope movements
indicated that a rapid failure mechanism was unlikely to develop. The modelling studies
described herein provided further support that rapid slope failure is unlikely. Moreover, the
numerical modelling provided important insight into the slope deformation mechanics,
enhancing the understanding of this regionally important phenomenon. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/5979 |
| Date | 05 1900 |
| Creators | Stewart, Thomas W.G. |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Format | 22721384 bytes, application/pdf |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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