Deformation properties of red mud-reinforced volcanic ash under long-term cyclic loading

This study investigated the dynamic properties of red mud (RM)-reinforced volcanic ash (VA) by dynamic triaxial tests. The effects of stress state (dynamic stress σ_d, confining stress σ₃), dynamic frequency (f) and load waveform (F) on the accumulative plastic strain (ε_p) have been investigated. The findings indicate a significant influence of the stress state on ε_p. When σ_d reaches 120 kPa, the specimens exhibit insufficient strength, leading to shear failure. As σ₃ increases, the dynamic stresses that lead to specimen destabilization also exhibit an upward trend. The effect of f on ε_p is limited. The ε_p does not exhibit a clear or consistent developing pattern with increasing f. As for the F, the ε_p exhibited by the specimens subjected to sinusoidal wave loads is less than that observed under trapezoidal wave loads. Shakedown theory classifies deformation responses into plastic shakedown, plastic creep and incremental collapse. The ε_p curve patterns of RM-reinforced VA exhibit plastic shakedown and incremental collapse without significant plastic creep characteristics under cyclic loading. A predictive model for ε_p under cyclic loading is established, which has good predictability. This study presents a novel application of VA and RM, offering substantial research insights into waste recycling.