Pullout response of cellular reinforcement under low normal pressures

Abstract

Pullout failure of reinforcement is one of the very important criteria in the ultimate limit sate analysis of internal stability of reinforced soil retaining wall. This is particularly of critical importance in upper layers of wall where the normal pressure on the reinforcement is low. Cellular reinforcement is found very effective and better performing for reinforced soil applications. However, pullout experimental study of such reinforcement has not been focused till date. Therefore, in the present paper, full scale laboratory pullout test set up has been designed, fabricated and developed to test the pullout resistance of cellular reinforcement. A series of pullout test was carried out with different heights of reinforcement, under low normal pressures of 25 kPa and 50 kPa. Deformation patterns of all reinforcement in pullout are studied. Finite element simulation is used to verify the experimental pullout response and found in good agreement with experimental load-displacement relationships. Suggested reduction factor <i>‘k’</i> is found decreasing with increase in height of reinforcement; yet, ultimate pullout resistance is found increasing with increase in the reinforcement height, to the height of 20 mm to 30 mm; after which, greater interference between the transverse members caused decrease in pullout resistance. Pullout interaction factor for cellular reinforcement is found increasing with increase in the reinforcement height.