Abstract Approach of determining shear strength of rock mass at present is briefly reviewed. Taking Maerdang hydropower station located in the upstream of the Yellow River for example,the relationship between shear strength and BQ rating is built up on the basis of rock mass classification,suggested shear strength by codes and in-situ large scale shearing test;and the relationship between BQ rating and GSI is also created according to field survey and measurement. Based on these,shear strength of rock mass at in-situ test point is estimated by Hoek-Brown criterion. The result shows that rock mass shear strength derived from this paper?s method is coincident with practical situation;while equivalent fraction coefficient from Hoek-Brown criterion is lower than test value and cohesion force is far greater than that from shearing test. It is shown by error analysis that the difference between experiment values and estimated ones is mostly induced by the span of minimum principal stress used in Hoek-Brown criterion. For this situation,some cautions and corresponding resolve methods while using Hoek-Brown criterion are reminded.
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Received: 20 December 2011
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