Numerical Simulation Study Of Influencing Factors Of Rock Blasting Funnel Based On Particle Flow Code

Engineering blasting technology has become one of the indispensable important supporting technology in China's economic and social construction.At present,facing with such a huge amount of blasting work,according to the blasting funnel effect generated by numerical simulation of rock blasting,if the blasting design scheme selects more scientific and reasonable blasting parameters not can only improve the blasting efficiency and protect the stability of surrounding rock mass,but also save a lot of explosives and detonators,thus reducing the blasting cost.Therefore,it is great significance to study the forming effect of blasting funnel in rock mass.Based on the mining project of Langshan limestone mine in Lu nan Zhong-lian Cement company,this paper collects the data of rock parameters and blasting parameters in the mine site,established the rock model by using particle flow discrete element PFC5.0 program,studied and summarized the influence of different macro parameters on the blasting funnel formed effection,finally carried out on-site blasting test verification.The main research contents are as follows:1.Particle Flow Code(PFC5.0)is used to explore the effects of particle stiffness,friction coefficient,elastic modulus of parallel bonding contact,normal bonding strength of parallel bonding contact and loading rate on macro-mechanical parameters of rock model,make methods for calibrating micro-mechanical parameters.2.The rock mass model is constructed to calibrated meso-scale parameters,and the blasting process of single-hole rock mass is analyzed.The blasting load is loaded by explosion point particle expansion loading method.Blasting simulation of rock mass with single blast hole includes internal and external effects.The radius of crushing zone generated by simulating internal effects of explosives is 2-3 times of the radius of blast hole,and the radius of crack zone is 130 times of the radius.The blasting funnel formed by simulating the external action of explosives has good forming effection.Therefore,PFC simulation of blasting effect produced by rock blasting can better reflect the act-ual engineering situation.3.Under the condition of different rock macro-mechanical parameters,the numerical simulation of macro-mechanical parameters on the forming effect of the blasting funnel is carried out,and the mathematical expressions of uniaxial tensile force,compressive force and elastic modulus on the depth,radius of the blasting funnel and the number of generated blocks are respectively fitted;Three kinds of blasting parameters,including the depth of explosive,the peak pressure coefficient of bore hole wall and the influence of delay time on the blasting effect are numerically simulated,and the forming effect of the simulated blasting funnel is summarized and analyzed.4.Field blasting tests including charge quantity and delay time are carried out through the delay system of nonel detonator,and the size of blasting funnel is counted.The simulation results of rock blasting are compared with the measured results to verify the rationality of the numerical simulation.