Flow characteristics of caved ore and rock in the multiple draw-point condition
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摘要: 基于離散元理論和PFC3D程序構建放礦模型,探究多放礦口條件下崩落礦巖流動特性,實現多放礦口條件下放出體及礦石殘留體形態變化過程的可視化.同時,將模擬結果與已有研究結論進行對比分析,驗證基于PFC程序的放礦模型在崩落礦巖流動特性研究中的可靠性.放礦PFC模擬結果表明,多放礦口條件下放出體形態會因各放礦口間的相互影響而產生交錯、缺失等程度的不同變異,并不是一個規則的橢球體.在單一放礦口和多放礦口條件下,放出體高度的變化趨勢均可概括為兩個階段:在放礦初始階段,放出體高度呈指數形式快速增加,隨放礦量的增加,其增長率逐漸減小;隨后,放出體高度將隨放礦量的增加而呈線性增長的趨勢.礦石損失率隨放礦口尺寸及崩落礦石層高度的增大而減小,隨放礦口間距的增大而增大.當相鄰放礦口間產生相互影響時,平面放礦方式與立面放礦方式相比,其礦石殘留量更小,且崩落礦巖接觸面呈近似水平狀態下降.Abstract: Based on the particle flow theory and PFC3D code,a draw model was constructed to research the flow characteristics of caved ore and rock in the multiple draw-point condition and visualize the form-changing process of the isolated extraction zone(IEZ) and the ridge hangover body. Simultaneously,the suitability and reliability of this draw model were validated in the flow characteristics study of caved ore and rock by comparative analysis between simulated results and existing research conclusions. Due to interactions among multiple draw-points,the IEZ's form produces different degrees of variation in the multiple draw-point condition,including interlacement and deficiency,which result in that the IEZ's form is not a regular ellipsoid. The height changing trend of the IEZ in both the isolated draw-point condition and the multiple draw-point condition can be divided into two stages:in the first stage,the IEZ's height rapidly increases in an exponential form at the initiation of draw and its growth rate decreases with the increase of ore-drawn mass; in the second stage,the IEZ's height linearly increases with the increase of ore-drawn mass. The ore loss ratio decreases when the draw-point dimension and the height of the caved ore layer increase,but it increases with the increasing of draw-point spacing.When adjacent draw-points interact with each other,compared with a facade draw mode,the ridge hangover mass is less in a plane draw mode,and the contact surface of caved ore and rock horizontally drops.
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Key words:
- underground mining /
- caving /
- flow characteristics /
- visualization
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