Aiming at the safety problem of second-step mining blasting in Lilou Iron Mine,the finite element software ANSYS/LS-DYNA is used to establish a corresponding blasting simulation scheme.According to the actual stope specifications,the length of the backfill body on both sides is 20 m,and the length of the middle mining body is 30m.The size of the bottom roadway is 4 m 4 m.The height of the backfill body and the ore body are both 25 m,and the thickness and row spacing are both 2 m.When arranging blast holes,it is considered to set 0.5 m、1.0 m、1.5 m and 2.0 m thick protective layer(that is,the ore body between the bottom of the blasthole and the boundary of the filling body) inside the ore body near the boundary of the backfill body,and both bottom and top initiation are used.After simulating the second-step recovery blasting under different schemes,the element most affected by blasting is selected at the corresponding position of the boundary of the backfill body for comprehensive analysis of stress,vibration velocity and displacement,so as to evaluate the overall stability of the backfill body under different schemes.The simulation results show that increasing the thickness of the protective layer in an appropriate range can effectively reduce the impact of blasting on the filling body.At the same time,under the top initiation scheme,the detonation position of the explosive is far away from the filling body,and the stress wave attenuation is more obvious.When the thickness of the protective layer is set to 1.0 m under the top initiation scheme,the effective stress peak value,the peak vibration velocity,and the peak value of the combined displacement of each monitoring point during the blasting process are 0.03 MPa,9.35 cm/s,and 0.07 mm respectively,all of which are in the safety range of the filling body.However,the thickness of the protective layer needs to be increased to 1.5 m when the bottom initiation scheme is adopted to keep each monitoring point in a safe state.In contrast,the thickness of the protective layer of the top initiation scheme is smaller,which has a better effect on the ore recovery rate.The simulation scheme of the top initiation method and the thickness of the protective layer of 1.0 m is verified through the field industrial tests by arranging a vibration meter around the stope.And the peak particle vibration velocity at the backfill boundary is fitted according to the relevant data and the Sadowsky formula.The peak velocity is 9.37 cm/s,which is consistent with the peak vibration velocity of the corresponding monitoring point in the simulation results.And the blasting effect on site is relatively positive,which further verifies the reliability of the simulation results and the rationality of the simulation scheme.