Research of the isolated extraction zone form and determination of optimal independent advance under different end wall angles
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摘要: 為分析端部放礦中放出體形態,獲得大結構參數下最優的崩礦步距,基于顆粒元理論和PFC3D程序,構建具有礦石散體細觀力學性質的放礦模型.通過已有研究結論與模擬結果的對比分析,驗證了基于PFC程序的放礦模型的可靠性.在此基礎上,開展18 m×20 m結構參數下不同端壁傾角崩礦步距研究.研究結果表明,不同傾角端壁條件下放出體形態不完整,并不是一個規則的橢球體.當放礦量相同時,放出體高度隨端壁傾角的減小而增大,放出體整體形態也隨之越來越"瘦長".在無限邊界和不同傾角端壁條件下,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.建議在18 m×20m結構參數下采用85°-90°的端壁傾角,4.8 m的崩礦步距.Abstract: In order to analyze the form of the isolated extraction zone (IEZ) in side drawing and get optimal independent advance with large structural parameters, drawing models with the mesomechanical properties of ore granular media were constructed based on the particle flow theory and PFC3D code. The reliability of the drawing models was validated by comparative analysis between existing research conclusions and simulated results. On this basis, a study on independent advance of side drawing at different end wall angles in the structural parameters of 18 m×20 m was performed. The results show that the IEZ form is incomplete and is not a regular ellipsoid at different end wall angles. When the drawn mass is equal, the IEZ height increases with decreasing end wall angle and the IEZ form becomes more and more slender. The trend of the IEZ height at both the infinite boundary condition and the boundary condition of different end wall angles can be divided into two stages:in the first stage, the IEZ height rapidly increases in the exponential form at the initiation of side drawing and its growth rate decreases with the increasing of drawn mass, while in the second stage the IEZ height linearly increases with the increasing of drawn mass. It is suggested that the end wall angle of 85°-90° and the independent advance of 4. 8 m should be used in the structural parameters of 18 m×20 m.
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Key words:
- caving mining /
- isolated extraction zone /
- end walls /
- tilt angle /
- independent advance
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