Eхperimental study on the effect of saturation on the triaхial mechanical properties of cemented tailings backfill

Underground in-situ strength of cemented tailings backfill(CTB) is significantly different from that of the laboratory curing sample, which is mainly caused by different temperature and humidity environment between underground and standard curing. In order to reveal the influence of curing age and water saturation on the CTB-water characteristic curve and mechanical properties of cemented backfill, the triaxial compression deformation characteristic parameters and the variation rule of matrix suction of backfill at different curing ages and saturation were analyzed by means of triaxial consolidation undrained compression test and CTB-water characteristic curve test. The results show that the longer the curing age, the denser the pore structure inside the CTB; the more difficult the dehydration, the higher the matric suction inside the backfill at the same saturation. The lower the saturation of the CTB, the higher the matric suction at the same curing age. The deformation characteristics of saturated CTB are related to internal structural strength, while the deformation characteristics of unsaturated backfill are mainly affected by matric suction, which is positively correlated with elastic modulus and negatively correlated with Poisson's ratio. With the decrease of saturation, the strength of CTB decreases slightly at first and then increases. © 2023 Central South University of Technology. All rights reserved.