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  本文選題：煤的成塊率 + 煤的動態(tài)特性�。� 參考：《安徽理工大學》2017年碩士論文

【摘要】：我國西部煤炭儲量豐富,是目前煤炭生產的主產地。然而,由于其成煤特性和生產工藝(包括綜采、機運、轉載等)的影響和作用,到達用戶時原煤較為破碎,粉煤多、成塊率低,嚴重制約了煤炭的使用價值。鑒于此,人們已著手進行各方面的研究,意欲提高原煤的成塊率,煤層內超長深孔爆破是為有效技術手段之一,研究煤的動態(tài)力學性質是其基礎。為此,論文以楊伙盤礦煤的原煤為例,采用實驗室沖擊試驗和數(shù)值模擬相結合,進行煤的沖擊動態(tài)力學特性研究。利用分離式霍普金森壓桿(SHPB)實驗裝置,采用Φ50mm錐形桿對煤進行沖擊試驗,探究不同氣壓(0.15MPa、0.20MPa、0.30MPa、0.40MPa、0.50MPa)下煤的動態(tài)力學特性。試驗分別在無圍壓和被動圍壓下進行,速度為2m/s～7m/s。通過采集到的數(shù)據(jù),用三波法得到應力、應變和應變率;再用數(shù)據(jù)處理軟件進行處理分析得獲得了應力、應變和應變率時程曲線以及應力-應變曲線。實驗結果表明:(1)應變率和加載速度相關性明顯,通過擬合得到ε=3.750v2-3.624v + 43;隨著加載速度的增加,應力-應變曲線整體上升,曲線在加載初期,存在短時間的彈性階段,之后呈現(xiàn)明顯的塑形變形,達到峰值以后,在很短的時間內,應變繼續(xù)增加,應力保持不變,最后進入卸載階段,應變會出現(xiàn)回彈現(xiàn)象;(2)被動圍壓下,煤的抗破壞能力有所增強,應力-應變曲線有所上升,軸向應力比無圍壓下增加1.0～1.3倍,應變回彈明顯,說明套筒可以增強煤試件的抗變形能力。利用ANSYS/LS-DYNA對煤的動態(tài)力學性質進行模擬,結果以發(fā)現(xiàn)煤的破壞從兩端和中間開始,并逐漸貫通,直至破碎。整合數(shù)值模擬的應力與應變數(shù)據(jù),得到煤的動態(tài)應力-應變曲線,相應的加載速度為3m/s、4m/s、5m/s和6m/s。通過比較,該應力與應變的變化趨勢與實驗曲線吻合,從而證明了實驗的正確性。
[Abstract]:The west of China is rich in coal reserves and is the main producing area of coal production at present. However, due to the influence and effect of coal forming characteristics and production technology (including fully mechanized coal mining, mechanical transportation, reloading, etc.), the raw coal is more broken, the pulverized coal is more, and the lump rate is low, which seriously restricts the use value of coal. In view of this, people have begun to carry out various aspects of research, with the intention to improve the block rate of raw coal, the ultra-long deep-hole blasting in coal seam is one of the effective technical means, and the study of dynamic mechanical properties of coal is its basis. Therefore, taking the raw coal of Yangyangpan Coal Mine as an example, the dynamic mechanical properties of coal impact are studied by combining the laboratory impact test with numerical simulation. In this paper, the impact test of coal with 桅 50mm conical rod was carried out by using split Hopkinson pressure bar SHPB. the dynamic mechanical properties of coal under different pressure of 0.15 MPA ~ 0.20 MPA ~ 0.30 MPA ~ 0.40 MPa ~ (0. 50 MPA ~ (-1) were investigated. The experiments were carried out at a speed of 2 m / s to 7 m / s under no confining pressure and passive confining pressure respectively. The stress, strain and strain rate are obtained by three wave method, and the stress, strain and strain rate time history curves and stress-strain curves are obtained by data processing software. The experimental results show that the strain rate has obvious correlation with the loading speed, and the fitting results show that 蔚 = 3.750v2-3.624v 43. With the increase of loading speed, the stress-strain curve increases as a whole, and the curve has a short elastic stage in the early stage of loading. The strain continues to increase in a very short period of time, and the stress remains unchanged. Finally, when the strain enters the unloading stage, the strain will appear springback under passive confining pressure. The failure resistance of coal is enhanced, the stress-strain curve is increased, the axial stress is increased by 1.0 ~ 1.3 times than that without confining pressure, and the strain springback is obvious, which indicates that the sleeve can enhance the deformation resistance of the coal specimen. The dynamic mechanical properties of coal are simulated by ANSYS/LS-DYNA. The results show that the destruction of coal starts from the two ends and the middle, and goes through gradually until it is broken. The dynamic stress-strain curves of coal are obtained by integrating the stress and strain data of numerical simulation. The corresponding loading speeds are 3 m / s ~ 4 m / s ~ 4 m / s ~ 5 m / s and 6 m / s / s. By comparison, the variation trend of the stress and strain is in agreement with the experimental curve, which proves the correctness of the experiment.
【學位授予單位】：安徽理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TD315

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