Study Of Pipeline Transportation Characteristics And Application Of Its Fly Ash Filling Material

The method of longwall mining is the main mining method currently used in coal mine, which makes the surface subsidence, groundwater depletion and coal waste of resources more and more serious. With the coal resources are exhausted day by day, coal resources “three under” needs to be solved. Filling mining is an effective method to solve the above problems. Fly ash filling materials is a kind of mixing filling materials, including cement, fly ash, coal gangue and other raw materials. It not only has the advantages of low cost, wide source, but also can solve a series problems, such as the fly ash and coal gangue occupies land, pollutes the environment and so on. However, the conveying characteristics of fly ash filling materials pipeline still lack systematic research.Conducting ration test on the foundation of the filling material’s physicochemical property, the article obtains optimum ratio of fly ash filling materials. Under the foundation of optimum ratio, tests are made on the fly ash filling materials in different concentration and fine coal gangue ratio’s initial shear stress, plastic viscosity and density; what’s more, the on-way resistance of fly ash filling materials and local resistance of bend were numerical simulated. According to the influence of Zhenchengdi mine 22618 planes engineering geological conditions, technology of mining and the study results on pipeline transportation characteristics, the filling pipeline system is designed. Draw the following conclusions:1)The physicochemical characteristics of raw materials were tested,The test results show that: fly ash is the low activity of low calcium endures ash; coal gangue is gangue clay rocks.2)Through ratio test of fly ash filling materials, the optimum ratio is: cement: fly ash: coal gangue =1:3:5, concentration of 78% 80%.3)Tests are made on the initial shear stress and the plastic viscosity of fly ash filling material with the differenr density and fine coal gangue ratio under the optimum ratio, the test results show that the greater the concentration of the filling material and the fine coal gangue ratio are, the greater the initial shear stress and the plastic viscosity of the filling material will be; tests are made on fly ash filling material with differenr density and fine coal gangue tatio under the optimum ratio, the results show that the greater the concentration of the filling material is, the greater the destiny will be, and the fine coal gangue rate has little effect on the density.4) Using Fluent（3D） for numerical simulation, this paper studied systematically the influence of four factors on the on-way resistance, the four factors are concentration of filling material, the percentage of fine coal gangue ratio, the flow rate and the diameter of the pipe. The research results show that the local bend resistance polynomial increases with the increase of filling material concentration, flow rate, the percentage of fine coal gangue ratio, and polynomial decreases with the increase of the pipe diameter.5) Using Fluent（3D） for numerical simulation, this paper studied systematically the influence of five factors on the local resistance of bend, the five factors are concentration of filling material, the percentage of fine coal gangue ratio, the flow rate, the diameter of the pipe and the curvature radius of the elbow. The research results show that the local resistance of bend polynomial increases with the increase of filling material concentration, flow rate, the percentage of fine coal gangue ratio, and polynomial decreases with the increase of the pipe diameter and the radius of the curvature of bend; when the concentration of filling materials, the percentage of fine gangue ratio, pipe diameter and curvature radius of the bend is larger, the center of dynamic pressure shifts outside hardly; when the flow rate becomes larger, it shifts outside easier. with meeting the performance requirements of filling materials, it is proposed that the concentration is 80%, fine gangue ratio of fly ash filling materials is 40%, flow rate is 1.8m·s^-1, the diameter of the pipe is 180 mm, and the radius of curvature of the bend is 1.5m.6)Based on the Zhenchengdi mine 22618 planes engineering geological conditions, technology of mining and the research results getting from various factors effecting on local resistance characteristics of pipe, the fly ash filling materials concentration of 80%, the percentage of fine gangue ratio of 40% and filling capacity of 163m3·h^-1 are determined. And then, the flow rate of 1.78 m·s^-1 and the pipeline inner diameter of 180 mm are determined. According the pipeline planning scheme, the systematic resistance of 16.92 MPa and pumping pressure of 9.26 MPa are determined through the study of the filling system’s numerical simulation, special purpose pump of HGBS200.14.800 produced by Hunan Feiyi Co. Ltd. is chose as the pump equipment,and wear-resisting seamless tube is chose with type ofφ 194mm×8mm, outside of Q345 and the thickness wear-resisting layer of 6 mm, pipe diameter is 186 mm.