Effect of tyre crumbs on the instability of sand under constant shear-drained stress path

Abstract

The instability of earth structures resting on granular materials, such as embankments and tailing dams, is caused by the infiltration of water which can lead to their failure. This paper presents the potential use of tyre crumbs (TCr) for controlling the onset of instability of sand. Constant shear-drained experiments were carried out on mixtures of sand and TCr to understand the onset of instability. Conventional drained shear tests were carried out on all samples up to a deviator stress of 200 kPa. The CSD tests were then carried out on the sheared samples by reducing the confining pressure until the onset of instability. The onset of instability was determined by a drop in stress, by second-order work and by the strain ratio approach. The value of mean effective stress at the onset of instability was found to decrease with the addition of TCr to the mix of up to 20% and then increase with further addition of TCr. The strain ratio approach was found to predict the onset of instability easily and efficiently, similar to the second-order work method.