Abstract: According to the characteristics of natural caving method such as large mining influence and serious ground pressure.In this paper,the natural caving method of Tongkuangyu Copper Mine is taken as the research object,combined with the current status of the mining of the main and auxiliary layers of the mine,the numerical simulation of the stress evolution of the ore body chassis during the natural caving method mining,and the stress at the junction of the main and auxiliary layers and plastic zone analysis.Aiming at the recovery of the amount of ore in the substratified highpressure ground pressure zone under extreme conditions,an orejoining scheme is proposed in which the lower part reopens the bottom structure,the central part is forced to collapse,and the upper part naturally collapses.The simulation and practical results prove that the bottom structure of the auxiliary layer is in a highstress area due to the pressure arch structure,especially before and after the main and auxiliary layer stopes are penetrated.Therefore,the bottom structure of the auxiliary layer should be strengthened in advance or deep holes should be used to discharge pressure engineering.Secondly,for areas where the geopressure area appears to be severe,you can wait for the geopressure to stabilize and then dredge or rebuild the bottom structure to carry out horizontal ore connection.

Key words: natural caving method,lower level access,main and sub level