Numerical Analysis of the Influence of Underground Mining on the Stability of Existing Slopes under Freeze-thaw Cycle
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 cy-cles.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 gravitation-al potential energy and dissipation energy are minimally affected by the number of freeze-thaw cycles and show limited sensitiv-ity 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.
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