Dehydration Of Hydraulic Filling In Negative Pressure

There are many problems of dehydration in backfill mine currently, such as poor effect of dehydration structures, the occurence of toxic or harmful gases by electric dehydration and high cost and low efficiency of concentration and dehydration in outsite stope etc. This paper, at the aim of developing new techniques of dehydration with negative pressure, studied the mechanism of dehydration with negative pressure, exploited a platform for simulation tests and developed numerical simulation procedures of FEPG(Finite Element Program Generator) to creat numerical model of dehydration in negative pressue. Combing neural network with chaos optimization methods, the optimum parameters of dehydration in negative pressure are obtained, which was applied in Wulong Gold Mine Sidaogou Zone and realized continuous filling, and good results were achieved. The main contents of the dissertation are as following:On the basis of percolation theory, the mechanism between vacuum dehydration and seepage velocity were revealed. The results show that the increase of seepage vilocity linearly depends on the subpressure and seepage coefficient, but it has an inverse relationship with lenghth of the filling body from which the water flows through. It is feasible to enhance seepage vilocity by increasing the subpressure.Through developing the platform for simulation test, designing vacuum dehydration test equipment and doing similar simulation tests, the best project of the vacuum extractor was determined. The testing results show that the effect of dehydration under negative pressure is related to the connection type of the vacuum extractor, which the way of parallel connection is optimal, increasing the size of percolation pipe network can also raise the dehydration speed, morever, reducing the distance between dehydration vacuum source and sites may enhance the dehydration efficiency. So an appropriate distance between vacuum tubes and other dewatering structures should be maintained, and negative pressure loss can be avoided.The FEM procedures were exploited based on FEPG to study the numerical simulation of filling dehydration under negative pressure, and the FEM models were established between the seepage vilocity and the influence factors, such as subpressure, heights of filling tailings, transverse spacing and longitudinal span of vacuum tubes, as well as adopting orthogonal experiment, the seepage velocities were obtained with different dehydration parameters. The results show that the seepage vilocity increases sharply with the increasing of subpressure in dehydration tube, while it is monotone decreasing with growing of the distance between the vacuum tubes, and lowering the heights of tailings also has an obviously positive effect on the dehydrated efficiency. The results of sensitivity analysis indicate that the negative pressure is the starkest and the most suspective factor on the effect of dehydration under negative pressure, and the height of tailing is the second factor.The prediction model between average velocity and vacuum pressure, filling height, horizontal and vertical spacing of dehydration tube was established using neural network, and the optimal dehydration parameters with negative pressure under certain conditions were obtained by the chaos optimization method combined with neural network.Through inventing vacuum dehydration of pipe cleaning system of filtration materials, developing dehydration device with negative pressure, and designing the optimal process parameters, the dehydration technology with negative pressure was used in Wulong Gold Mine Sidaogou Zone. The industrial experiment of negative pressure dehydration shows that dehydrating water with negative pressure is 3.7 7.6 times of the natural dehydration, and the effect is remarkable. When the vacuum dewatering system is working, the vertical and horizontal pressure greatly is reduced in the closed wall, the filling system can be guaranteed continuous work, and expected results is achieved.