Modeling the thermo-hydro-chemical behavior of cemented coal gangue-fly ash backfill

Cemented coal gangue-fly ash backfill (CGFB), which is a mixture of coal gangue, fly ash, cement and water, is being extensively utilized in underground coal mines of China for subsidence control and waste management. One of the most significant evaluation criteria for CGFB is its mechanical performance, which is affected by the thermal (T, e.g., temperature evolution), hydraulic (H, e.g., suction development) and chemical (C, e.g., binder hydration) factors and thus subjected to the coupled THC effects. Modeling the coupled THC behavior of CGFB is crucial for effectively estimating the mechanical performance of CGFB. Therefore, a numerical model is developed to analyze and predict the coupled THC behavior of CGFB and its evolution versus time. The analysis and prediction results of the developed THC model are compared with laboratory investigations conducted on CGFB. There is a good agreement between the modeling results and experimental data, validating the capability of the developed model to simulate the coupled THC responses in CGFB.