BEHAVIOUR OF FOOTINGS ON REINFORCED BACKFILL OF A RIGID RETAINING WALL

Abstract

Three dimensional tests were performed on a rectangular (10 cm x 20 cm) surface footing resting on reinforced backfill of a rigid retaining wall and subjected to vertical central load. It was intended to study the behaviour of the footing resting on the reinforced backfill of a rigid wall. The reinforcement used were strips of bamboo and aluminium. The study was carried out on cohesionless soil placed at a density of 1.6 gm/cc using the rainfall method. The edge distance of the footing from the wall was varied from 0.5 B to 5 B. (B=footing width). The experiments were conducted in a rigid tank of size 220cm x 100cm and 110 cm. One side of the tank was constituted by the model test wall of 99 cm height which was hinged at its bottom to the tank base. Twenty eight tests were conducted which were of two types. First type included load tests performed on the footing while the wall was kept in vertical position with the help of clamps at the top. Pressure settlement characteristics of the footing for these tests were obtained by drawing pressure v/s settlement curves and ultimate loads were read off the curves. In the second set of tests top clamps of the wall were removed either before the placement of test footing or after the footing was placed, and the wall was allowed to rotate about its bottom to attain the active state. Moment v/s rotation of wall, plots were drawn to compute the magnitude, of active moment. Settlement v/s rotation of wall curves were also plotted. Both types of tests were conducted for unreinforced and reinforced backfill. In addition, non dimensional correlations were also obtained in respect of ultimate loads, settlements etc. A pertinent review of the literature on the topic has been included.