Determination of reasonable horizontal distance between open-off-cut and slope under the combined mining mode of open-pit with underground mining

In order to study the slope stability when he combined mining mode of open pit and underground mining, we calculated the slope stability of open pit under complicated mining conditions based on the numerical simulation and the upper bound method. The stability of slope was evaluated when the horizontal distance between open-off-cut and slope was increased. The results show that the slope becomes more stable with the increase of the horizontal distance and the collapse effect of mining on the slope decreased. When the horizontsl distance increases by 20 m, the slope as a whole is quite stable and can meet the stability standard.