Effect of tyre crumbs on the stability of sand under constant shear drained stress

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 for controlling the stability of structures made of sand. Constant shear drained experiments were carried out on mixtures of sand and tyre crumbs to understand the onset of instability. Conventional drained shear tests were carried out on all samples up to a deviator stress of 200 kPa. Tests were then carried out on the sheared samples by reducing the confining pressure until the onset of instability. This was determined by a drop in stress, by second-order work and by the strain ratio approach. The value of mean effective stress at instability was found to decrease with the addition of tyre crumbs to the mix of up to 20% and then increase with further addition of tyre crumbs. The strain ratio approach was found to predict the onset of instability easily and efficiently, similar to the second-order work method.