Stability and Settlement Analysis of a Lightweight Embankment Filled with Waste Tyre Bales over Soft Ground

The waste tyre-derived products, including whole tyres, tyre bales, shreds, chips, and crumb rubber, have begun to be used in various geotechnical applications. In particular, the use of tyre bales in the construction of a lightweight embankment on the soft ground has the potential to satisfy the demand for low-cost materials exhibiting such beneficial properties. This paper presents the comparison between the common medium sand-filled embankment and two tyre-baled structures with various granular interlayers: medium sand and rubber aggregate. To assess the efficiency of tyre bale application in soft ground conditions, two subsoils were considered in the study: sandy clay and silty clay. The stability and settlement analysis of embankments, as well as subsoil bearing capacity checking, were performed for all structural cases. Bishop’s limit equilibrium slicing method and the finite element method were used in the embankment and subsoil analysis. The comprehensive testing of tyre bales and filling materials was also carried out to obtain the set of parameters used in both analyses. The comparison allowed qualitatively assessing the effectiveness of using waste tyre bales as a filling of road embankment when founded on soft ground. The analysis revealed that the application of tyre bales generally enhanced the embankment stability, effectively reduced the embankment settlement, and reduced the normal stress in the subsoil. In the tyre-baled embankments, the slip surface is located mostly within the embankment slope, showing good rotational stability, independent of subsoil conditions.