Biocementation as a non-intrusive soil stabilisation technique offers a potentially non-disruptive solution for rehabilitating road and railway foundations, yet its effects on the deformation behaviour of granular materials under traffic-type cyclic loading remains poorly understood. This study presents a detailed investigation into this problem through an extensive programme of single-stage, one-way cyclic triaxial tests conducted on a representative aggregate, uncemented and biocemented to different levels. The results show that, when subjected to consistent levels of normalised stress ratio (NSR) across the critical zone, both uncemented and biocemented aggregates exhibit a transition from stable to unstable behaviour. Biocementation effectively improves deformation resistance in the stable state but significantly exacerbates instability in the unstable state. Key mechanisms underlying the observed responses are interpreted from a micromechanical perspective, with the competition between structural self-stabilisation and load-induced destabilisation postulated to govern the onset of instability. Based on the analysis of strain rate, a mechanistic-empirical model is derived to predict the evolution of permanent strain, yielding a close match with experimental results. Finally, comparison with previous multi-stage test results reveals contrasting effects of stress history in uncemented and biocemented aggregates, which are well-explained using the postulated mechanisms.
Fu et al. (2026) studied this question.