Study On Simulation Model Of Time-space Evolution Of Granular Flow And Its Applications

The mechanism and simulation method of rock ore granular flow is an important research direction in mining theoretical research. by combining the stochastic medium theory with the 9-block model, the void-filling method of granular flow and time-space evolution model of granular flow are proposed in the theses. They are able to solve the flow problems with different granularities and time factors of granular flow and have been used in stope-caving and ground subsidence simulations. Two simulation systems of ore-drawing and ground subsidence by combining the computer programming and graphics techniques have been developed and reported in the theses. So far, they have been successfully used in mining practiceFirst, the motion of the 9-block model and the assignment of its probability distribution are investigated. By considering the ore looseness different parameter m can be assigned to the 9-block model. Thus, the probability assignment can be greatly simplified and different recovery index can be obtained. Based on the 9-block model a 3-D ore draw simulation system(SLS) is developed. The system can be used in simulation experiment to obtain the relationships of structural parameters and recovery index as well as the ore draw mode to the recovery index with respect to ore draw step mixed rock. The simulation is in good coincidence with the practice.Second, considering on the drawbacks of the 9-block model a granular flow void-filling method is proposed based on the stochastic theory and mechanical criteria. This innovative method combines the merits of both the stochastic simulation and the discrete element method. A 2-D ore draw simulation system(VFMS) is developed based on the void filling method. Different structural parameters are taken in the simulation experiment. The results are in good coincidence with that obtained by the SLS simulation. It means that the void filling method can be used in granular flow simulation.Finally, based on the deep investigation of the 9-block model and the stochastic medium theory, by assuming that the ore rock has the Kelvin rheological property, a time space evolution model is established. This model can solve the time space problems involving caving loose body flow and also give the method determining the time factor and probability distribution. Two inversion methods of time factor evaluation are also given in the paper. Based on the time space evolution model of the granular movement, a ground subsidence simulation model is developed. This model has been used in the simulation experiment of ground subsidence caused by mine goaf in Mengjiagang iron mine. Important results have been obtained. It shows that this model is good for ground subsidence simulation.In the state calling of construction of numerical mines the research and development of the mining engineering software is the main task of mining researchers. Based on the theoretical research, three simulation systems, namely the computerized simulation system for caving ore drawing, the 2-D ore drawing simulation system based on the void filling method and the simulation system for ground subsidence prediction have been developed in the theses. It is believed that the research efforts reported in the theses will push forward the development of mining engineering software and will lay a fundament in the construction of numerical mines in our country.