Abstract: Taking the goaf of a lead-zinc mine in Fujian as the research background，a three-dimen⁃ sional mechanical analysis model is established through a detailed investigation of the natural geographical conditions of the mining area，and the stability of the goaf is quantitatively evaluated. Using numerical simu⁃ lation technology and finite difference method，the stability of single goaf and goaf group is simulated. It is found that it is affected by many factors such as original rock stress，structural plane，lithology and ground⁃ water conditions. Based on the comprehensive evaluation index system of stability，the stability of surround⁃ ing rock in goaf is divided into four grades : stable state，basic stable state，unstable state and unstable state. Among them，three unstable goafs are located in the middle section of 160 ~ 170 m，and there is a high risk of instability. In view of the different goafs，a treatment scheme based on closed isolation is pro⁃ posed，supplemented by waste rock filling and roadway reinforcement measures. At the same time，the feasi⁃ bility of pillar recovery is evaluated，and the recovery principles and conditions are determined. The re⁃ search shows that reasonable goaf treatment and pillar recovery scheme are very important to ensure the safe production and efficient utilization of resources. It is suggested to take effective ground pressure control mea⁃ sures and adjust the mining scheme in time to ensure the long-term stable operation of the mine.

Key words: goaf stability, numerical simulation, finite difference method, pillar recovery, ground pressure control