Analysis Of Blasting Effect Under Coupling Condition Of Rock And Backfill

Filling mining method is one of the mining methods widely used in underground metal mines.In the process of blasting and falling of filling mining,the rock should be fully broken,the bulk rate should be reduced,and the stability of filling body should be guaranteed.Therefore,studying the interaction mechanism and deformation evolution rule of rock and backfill under the coupling condition becomes the key problem of backfill mining blasting.In order to ensure the safety of mine production,it is very important to evaluate and analyze the stability of rock contact zone in blasting mining.At present,it is urgent to study the interaction mechanism and deformation evolution law of rock and backfill under blasting,so as to seek the optimal rock blasting effect under the condition that backfill is not destroyed and stable.The uniaxial impact experiment is carried out on the rock filling body coupling body by means of the Hopkinson bar impact experiment to study the dynamic characteristics of rock filling body coupling body under blasting.The results show that the average strain rate and incident stress amplitude of the coupling body under uniaxial impact load are all related to the impact velocity,and the incident energy has a good linear positive correlation with the impact velocity and the average strain rate.The dynamic compressive strength of the coupling body first increases and then decreases with the increase of the average strain rate,and finally tends to be stable.When the strain rate is 20?45s-1,there is a significant strain rate effect.The stress-strain curve of the coupling body changes obviously with the average strain rate.When the average strain rate below 60s-1,the stress-strain curve is "stress sag" type;when the average strain rate above 60s-1,it is "stress rebound" type,and the reflected wave has a great impact on the failure of the coupling body.SHPB experimental numerical simulation is carried out for four coupling rock filling bodies with different coupling forms.Four coupling models of rock and filling body with axial coupling,radial coupling and radial coupling with free surface are established.Numerical simulation calculation is performed using GDEM numerical simulation method,and their axial vibration velocity and displacement,as well as axial and radial stress data at different moments are obtained.The stress and strain on the free face of backfill are greatly affected,and the backfill can be well protected by the existence of free face.More and larger free surface should be created for rock blasting as far as possible.As long as the free surface is controlled reasonably,the rock can be fully broken without damage to the filling body.Established in combination with the mining practice to the level of filling on the layered approach the lateral blasting mining model and numerical simulation,the actual mining side blasting in rock breakage and damage situation of filling body,the simulation results show that after the bursting of the lateral rock breaking is full,the backfill is basically intact,blasting vibration on the front does not lead to a goaf filling body damage.Figure 73;Table 8;Reference 51...