A series of triaxial tests were conducted to investigate the mechanical behaviors of permafrost-associated methane hydrate-bearing sediments under different mining methods (depressurization/heating under exhaust/non-exhaust conditions, CH4-CO2 replacement). The results indicate that both depressurization and heating will decrease the stability of methane hydrate-bearing sediments containing ice which prepared by a mixture method, due to the loss of bearing capacity of methane hydrates and increasing pore pressure; the sediments dissociated under exhaust conditions present much higher failure strength and elastic modulus than those dissociated under non-exhaust conditions, which means that the instability of hydrate-bearing sediments containing ice is likely to be induced more easily in the low permeability regions in certain conditions; the sediments dissociated by depressurization are more stable than those dissociated by heating, due to the effect of ice re-formation under sub-zero conditions; and the failure strength and elastic modulus of methane hydrate-bearing sediments containing ice (mixture method) are slightly lower than that of the CO2 hydrate-bearing sediments containing ice (mixture method) under various conditions, which means that the layers may possibly keep stable when the methane hydrate is completely replaced by CO2 hydrate. (C) 2015 Elsevier Ltd. All rights reserved.