A RATIONAL DESIGN OF GRAVITY TYPE RETAINING WALLS

Abstract

Retaining walls in the form of abutments and wing walls have been constructed along various canal systems in the State of Uttar Pradesh. They have a base to height ratio varying from 0.35 to 0.57 and have been existing for last 80 to I00 years. These seem to be on the lower side than those for the walls being designed on the basis of present prectice, accord- ing to which the base to height ratio works out to 0.70 to 0.85. To reconcile this difference, prototype study of 19 existing retaining walls has been performed and the present conditions under which they are standing, are worked out. Laboratory tests, in the form of Block Shear Tests, Tensile Strength on masonry blocks, Direct Shear Tests for wall friction angle, Triaxial Shear Tests on the backfill material, have been carried out. The present work indicates that the existing walls must be experiencing tension varying from 3-23 p.s.i. and a factor of safety against sliding of less than unity. As the retaining wails are standing in the field withcut any distress, hence the conditions to which they have been subjected, must be different from those postulated by the present design practice.