During underground mining of metal resources

the surrounding rock of the goaf is deformed and damaged

which will affect the safety of underground mining. The failure mechanism of surrounding rock in the underground goaf at Jinshandian East District is studied by means of field investigation

displacement monitoring

microseismic monitoring and theoretical analysis. Considering the influences of horizontal in situ stress and caving rock mass

the failure mechanisms of surrounding rock of the goafs in the hanging wall and footwall are obtained

i.e. toppling–slipping failure and buckling–slipping failure

based on limit equilibrium theory and energy method

respectively. Under the cutting action of the steeply dipping discontinuities

the surrounding rocks of the hanging wall and footwall form an anti-dip structure and a forward-dip structure

respectively. Under the action of horizontal in situ stress

the rock mass with steeply dipping discontinuities in the hanging wall topples to the side of the goaf

and the deformation and damage of the rock mass leads to the activation of the fault F4. As the mining deepens

the number and extent of the failure rock mass continues to increase

and a deep slip surface is formed and traversed the fault F4. Under the action of horizontal in situ stress

the surrounding rock of the goaf in the footwall induces the slip of the fault F1 at the boundary of the ore body

and simultaneously causes the buckling–slipping failure of the rock column with forward-dip discontinuities

and forms a slip plane along the discontinuity surface.