To solve the problem of the filling bodies failure on both sides of the room caused by differential blasting of large diameter deep holes in underground mine, the stress field generated by differential blasting should be studied to determine a reasonable edge hole spacing and a delay time between the holes. According to the stress wave propagation and attenuation law, the front and rear detonation hole distance, delay time, and edge hole distance generated by complex stress field were determined. Furthermore, the superposition of the stress wave generated by the two-hole differential blasting in the blasted rock mass and the filling body was analyzed according to the wave theory. The stress field function analytical formula of the two-hole differential blasting was obtained. Meanwhile, the collapse range of the blasted rock mass and the failure range of the filled body under different side hole spacing conditions under the same hole spacing and delay time were determined. The LS-DYNA numerical simulation software established six numerical models, and the stress critical points were selected in the blasted rock mass and filling body for analysis after simulating the initiation of explosives under different schemes. The simulation results show that different edge hole distances had almost no effect on the collapse range of the exposed rock mass when the distance between edge holes was more significant than the range of the crack zone. Appropriately increasing the distance between edge holes can effectively reduce the damage caused by stress waves to the filling body. Finally, the field industrial test of four groups of blasting parameters was carried out, and the optimized blasting parameters were determined as the spacing between the two holes on the same side was 2.0 m, the delay time between the front and rear initiation holes was 9 ms, and the side hole spacing was 1.8 m.

In deep hole bench blasting in open-pit mines, several issues arise including high consumption of explosives per blast, large bulk and foundation ratio, increased overall cost, inadequate loose blasting pile for shovel loading, and excessive blasting vibrations that affect slope stability. This study focuses on the controlled blasting project of deep-hole benches in Duobaoshan open-pit mine. Theoretical analysis was conducted to establish an analytical formula for the stress field caused by hole-by-hole blasting. The parameters such as hole and row spacings, minimum bottom resistance line, and delay time between holes were determined based on this formula. The LS-DYNA software was utilized to analyze the blasting stress and crushing range under these parameters. Furthermore, six groups of industrial field tests were carried out at Duobaoshan open pit mine using different blasting parameters. These tests aimed to determine the variation patterns of powder factor, fragmentation size, and looseness characteristics among different explosives. The optimized parameters for controlled deep hole bench blasting in Duobaoshan open-pit mine were verified and determined through these experiments. The main research findings are as follows:(1)Under the coupling charge condition of Duobaoshan open-pit blasts and utilizing theoretical derivation and analysis of stress fields from hole-by-hole initiation method, it was found that the influence of stress field distribution is limited to front and rear holes with a delay time between holes set at 17 ms.(2)UAV tilt photography technology along with mobile phone photography can be employed to collect data on detonation piles' characteristics and lumpiness size at blast sites. Analysis based on collected data provides effective insights into looseness levels.(3)For the 178 mm of the hole diameter and 17 ms of the holes' delay time of the deep hole bench blasting in Duobaoshan open-pit mine, the powder factor is 0.60 kg/m³ and the hole row spacing is 7 m×5 m under the conditions that the blast lumpiness is less than 60 cm and the looseness is greater than 1.45 shovel loading.