Abstract: The deformation modulus of rock mass is generally directly determined by field tests and indirectly estimated by relationships with other geo-parameters. For dam foundation rock mass,it is impractical to carry out sufficient field tests to verify the improvement of modulus after consolidation grouting. In this research,several relationships for estimating the value of grouted rock mass deformation modulus were proposed on the basis of longitudinal wave velocity,which can be economically and conveniently measured by geophysical prospecting. Gomal Zam Dam multipurpose project was taken as an example. This approach could be applied to determine the rock mass deformation modulus of similar projects or projects in lack of field data.

Key words: deformation modulus, consolidation grouting, dam foundation rockmass, field deformation test, longitudinal wave velocity