PRESSURE DUE TO EARTHBACKING ON GRAVITY DAMS

Abstract

Strengthening of existing masonry dams) which are unsafe against earthquake is a very vital problem. Pre-stressing the dam, adding masonry to full section of dam or providing butteresses .at suitable intervals for strengthening a gravity dam are some of the techniques usually adopted. But these methods are quite costly. One alternative method is backing the dam by earthf ill on its downstream face. This method is quite economical as well as easy from the construction point of view. The principal aim of this investigation is to find the pressure distribution due to backfill during active and at rest conditions. A method for this has been developed. As the soil pressure depends on a number of quantities such as angle of internal friction, angle of wall friction, unit weight of soil etc. a parametric study of these quanti-ties has been done. From this study, it is found that pressure distri-bution is nonlinear and the point of application of earth-pressure lies at 3/8th the height of backfill above base. Earth pressure decreases with the increase in angle of internal friction and the angle of wall friction.