Abstract: As shallow resources are gradually exploited into deeper areas，the problem of high ground stress in deep mines becomes more serious.In order to study the unilateral high in-situ stress caused by mining and cutting engineering during deep metal mine recovery，the formulas of explosive crushing circle radius and fissure circle radius extension length in deep infinite rock mass are theoretically analyzed and deduced.The results show that the initial in-situ stress has an inhibitory effect on the explosive cracking gap of explosives，and the inhibitory effect on the expansion of the crack ring radius is more obvious.The model tests of combined hole blasting under different unilateral confining pressures were carried out.The results show that with the increase of unilateral confining pressure， the volume of the combined hole blasting funnel is reduced，the unit consumption of explosives is increased，and the increase of the unilateral confining pressure also suppresses the combined hole blasting.Based on theoretical analysis and model tests，a three-dimensional model of the underground stope in Zambia Chambishi Copper Mine was established with the LSDYNA software.And the optimization study of the combined hole blasting parameters （hole distance，resistance line） under the unidirectional confining pressure of 15 MPa were conducted.The study results show that when the resistance line W=1.8 m and the hole distance a=2.4 m， that is，when W=23.68[?] and a=31.58[?] （[?] is defined as the hole diameter），the volume of the blasting funnel reaches the maximum value，and the maximum energy efficiency of the explosive can be obtained.The above study results have a theoretical guiding role for the optimization of on-site blasting parameters in mines.

Key words: Underground mining, Initial ground stress, Combined hole blasting, Model test, Numerical simulation