TREATMENT OF ROCK FOUNDATION FOR EMBANKMENT DAM BY CEMENT GROUTING

Abstract

c tth the development of highly .productive earth-moving equipment and the science of soil mechanics and rock rre chant CS, embank went dams have not .only outnumbered other types but have also outclassed them with respect to height and economy in cost and time Of ,construction. However, due to most of the good dam-sites having already been harnessed in many countries, choice has increasingly to be made from amongst sites with adverse found-ation conditions favouring embankment dams. Failure of largo dams can bs catastrophic. The safety of a dam being mostly in the hands Of the foundation, the importance of adequate found-ation treatment needs no emphasis. To be structurally stable, the foundation of an embankment dam should be as strong as the fill material. It should not be susceptible- to excessive or differential settlement and piping and there should not be a l a k of secure junction between the fill and the foundation. The foundation has also to be accept-ably impervious from the point of view of water .loss. The treatment, therefore, involves U) removal of undesirable mate--ri al and preparation of a desirable contact surface, (ii) treat-ment of faults, seams, shear zone, cavities and other geologic weakness, (iii) consolidation and curtain grouting, and (iv) drainage. The dissertation deals with all the aspects of treatment of rock foundations with special ergphasi s on cement grouting procedures and equipment. General principles and procedures have been enumerated and illustrated by a detailed study of six high embankment dams from different regions with different geologic and other features.