Research On The Breakage Mechanism Of Coal Flow Impact Bin Wall Of Large Coal Bin

Aiming at the problem of coal flow impact damage in a large number of active coal bunkers at the national coal base in northern Shaanxi,a systematic study on the movement law of coal flow blocks into bunkers of large active coal bunkers of 10 million tons is carried out using the research methods of experimental testing,field research,numerical simulation and theoretical analysis.The discrete element model of particle flow impacting coal bin wall was established to study the impact damage law caused by different impacting processes to the coal bin wall and propose the technical solutions to control the coal flow impact damage.Aiming at the damage problem of coal flow silo of 18 million tons capacity in Lemon Tower,we carried out the damage study of existing coal silo and optimized the damage protection,which provided scientific support for the operation and production safety of large coal silo.The main research results are as follows.（1）Determination of physical and mechanical parameters of coal flow and formulation of simulation parameters.The uniaxial compressive strength,density and other parameters f the samples were measured in the laboratory according to the rock physical and mechanical properties measurement standard.（2）The motion of coal flow hitting the bin wall was simulated by EDEM software.Based on the principle of control variable method,the velocity,density,angle and volume size are controlled and limited,and the size of the energy accumulation on the impacted surface is used to reflect the impact degree of the impacted surface;through simulation,the degree of influence and relationship of each factor on the impact degree of the bin wall are analyzed,and the transport method（coal flow movement method）with the least impact degree on the,bin wall is fitted.（3）Establishing a coal flow impact damage model of the coal bin wall and simulating the impact resistance of the new repair material.The recovery coefficient is introduced to value the velocity after impact,and the amount of kinetic and potential energy loss is calculated to obtain the cumulative value of energy of the bin wall,to judge the incidence velocity and angle of the minimum impact damage,and to verify the rationality of the minimum impact scheme.At the same time,the new material is selected as the repair material of the impacted wall,and the simulation of the new material in the process of impact is carried out,and the results show that the introduction of the new material can effectively improve the impact state at this stage.（4）Based on the simulation and theoretical calculation,the spiral chute is optimized for the existing coal drop bin.The optimized coal drop silo is optimized according to the transportation scheme of minimum impact degree and the force state of coal flow movement in the spiral chute,and the optimized coal drop silo is simulated for production transportation.The results show that the optimized coal drop silo has less energy accumulation,the impact degree is reduced,and the central low-speed coal drop can be realized,which reduces the secondary impact.Meanwhile,the possibility and safety simulation of adding spiral chute to the optimized coal drop silo is analyzed by FLAC^3D.