Study On The Wall Damage Of Ore-pass Under The Impact Of Ore-rock

In the actual production of underground mine,ore-pass plays an important role in transporting ore and rock because of its own characteristics.With the exhaustion of the front resources of various minerals and the implementation of the strategy of marching to the deep,the stable operation of the ore-pass becomes more and more important with the mine production,and the impact of the ore rock block on the wall of the ore-pass is an important reason for the instability,deformation and blockage of the ore pass.The study of crack propagation law in shaft lining material under impact load of ore and rock is helpful to analyze the failure mechanism of ore pass collapse and blockage.The crack propagation and dynamic response characteristics of the shaft lining of ore pass section under the impact of ore-rock are analyzed by using the discrete element numerical simulation technology.The crack propagation law,dynamic mechanical characteristics and damage mechanism of the shaft lining of ore-pass section under the impact of ore-rock are explored.The research has achieved the following main results:(1)It is found that the impact angle is related to the chute angle,the velocity and the inner diameter of the shaft when the ore block first impacts the shaft wall by analyzing the mechanical mechanism of impact load on inclined plane,it is found that there are two directions of impact force in the model,and there is a functional relationship between the two directions and the diameter of the specimen and the impact force of falling weight.(2)A method of preparing internal prefabricated crack specimen is developed,in which a special shaped thin paper sheet is put into the pouring specimen,and after the specimen is solidified and cured,the preparation of internal prefabricated crack specimen is realized,the static parameters of the specimen were measured.(3)The effect of impact angle and impact frequency on the damage of the model is studied by using the discrete element numerical model,the angle of inclined plane is related to the shape and number of new cracks in the model,and the number of impact is related to the deformation and damage degree of the model.(4)Combined with the numerical simulation results of the discrete element model,it can be seen that the smaller the angle of the inclined plane,the more loosely distributed the new cracks are at the left end of the prefabricated crack,and the main starting point is at the lower end of the inclined plane,and the larger the angle of the inclined plane is,most of the new cracks are distributed at the top of the precast crack,and the precast crack is the main starting point.(5)Based on the physical model parameters in the laboratory,the impact discrete element model of ore and rock at a specific angle is established to study the influence of impact energy and energy parameters on the damage of the model,the experimental results show that the shape of crack and strain curve in the model is only related to the angle of inclined plane,and the change of impact energy and parameter group only affects the number of cracks and dynamic mechanical parameters.(6)By analogy with the discrete element numerical model of rock and ore impact shaft lining,the damage mechanism of rock and ore impact shaft lining is analyzed,the wellbore experienced four stages: initial damage,damage accumulation,macro-crack generation and crack propagation,the factors that affect the damage degree include the angle between the rock and the wall,the number of times of the impact,the rate of the impact mass and the degree of smoothness.