Abstract: To study the stability of existing freeze-thaw slopes under different underground mining conditions,this paper conducted numerical simulations using 3DEC to analyze the mining stability of the slopes considering different freeze-thaw cycles. The analysis focused on the effects of different underground mining speeds and freeze-thaw cycles on the slopes regarding displacement,stress,plastic zone,safety factor,and energy. The results indicate that increased freeze-thaw cycles increase slope displacement and stress. The vertical stress distribution in the roof of the goaf exhibits a symmetrical pattern with the coal pillar at the center. When the mining speed changes from 30 meters/ step to 50 m/ step (mining a distance of 200 m),the maximum vertical stress of the roof increases from 10 MPa to 30 MPa. The extent of tensile failure on the surface of the freeze-thaw slope gradually increases with an increase in the number of freeze-thaw cycles. The safety factor of the slope decreases as the number of freeze-thaw cycles increases,and there is a risk of instability after 20 freeze-thaw cycles. The freeze-thaw slope′s gravitational potential energy and dissipation energy are minimally affected by the number of freeze-thaw cycles and show limited sensitivity to changes in mining rate,even under the same freeze-thaw cycle conditions. However,the kinetic energy released by the freeze-thaw slope increases with the number of freeze-thaw cycles. As the number of freeze-thaw cycles increases,the difference in kinetic energy released at different mining speeds also increases.

Key words: freeze-thaw cycle,underground mining,mining speed,existing slope,energy evolution