Abstract: Underground phosphate mines are subject to long-term groundwater erosion,and water-rock interaction is a common problem in underground mining engineering,which can easily induce geological disasters under excavation disturbance. In order to investigate the damage characteristics of phosphate rock under different water-rock interaction,uniaxial loading test of phosphate rock with different water content was carried out with the help of acoustic emission instrument. The macroscopic damage characteristics and mechanical properties of phosphate rock under different water content states were analysed, and a model of the internal damage variables in the specimen was constructed with the help of acoustic emission ring counting characterisation. The above study results show that:① Water has a weakening effect on the cemented materials in the phosphate rock,which in turn has a deteriorating effect on the mechanical properties of the phosphate rock;② Water affects the damage mode of the phosphate rock,and with the increase of water content,the damage mode of the phosphate rock changes from brittle to plastic damage,which is manifested by the fact that the peak strain of the specimen of the phosphate rock increases with the increase of its water content;③ As the water content of phosphate rock increases,the time lag of acoustic emission from loading to damage is relatively longer,and the acoustic emission ring counts and energy gradually decrease;the evolution of internal damage variables of phosphate rock with different water content is synchronous with the whole loading process of the rock samples. The above study results can provide theoretical reference for the safety mining of underground phosphate mines.

Key words: hydrological interaction,water content,phosphorite,damage properties,acoustic emission