Centrifuge model tests on geotextile-reinforced slopes

Abstract

This paper addresses the static response of geotextile-reinforced slopes resting on a firm foundation to the self-weight loading imposed in a geotechnical centrifuge at pre-failure and at failure. A series of centrifuge tests were carried out on model geotextile-reinforced sand slopes with different types of reinforcement, spacing and slope inclination. A wrap-around technique was used to represent a flexible facing. In order to initiate failure in the reinforcement layers, the ratio of the length of the reinforcement to the height of the slope was maintained as 0.85. Reinforced slope models were subjected to varied g-levels (in steps of 5g from 10g onwards) up to a maximum target g-level of 75g or to collapse, whichever occurred first. A digital image analysis technique was employed to arrive at displacement vectors of markers glued to the reinforcement layers. The displacements were used to compute and analyse the strain distribution along the reinforcement layers, and to identify the peak strain distribution pre-failure and at failure. The development of a particular type of failure mechanism was found to depend upon the tensile strength-strain characteristics of a reinforcement layer. Maximum peak strain in the reinforcement layers was observed to occur at mid-height of the slope. With an increase in slope inclination from 2V:1H to 5V:1H, the magnitude of maximum peak strain was observed to increase, and its location was observed to move downwards from mid-height of the slope. Stability analysis of the reinforced slope models was found to be in good agreement with physically observed centrifuge test results.