發(fā)布時間：2018-04-19 23:34

  本文選題：堅硬頂板 + 深孔爆破　； 參考：《太原理工大學》2017年碩士論文

【摘要】：我國煤炭資源儲量豐富,堅硬頂板煤層較多。厚硬頂板的存在嚴重威脅采煤工作面的安全生產,特別是在初采期間,頂板完整性較好,在短期內不會自行垮落,使得初次來壓步距加大。一旦頂板大面積垮落,采空區(qū)瓦斯瞬間涌出,極易造成頂板和瓦斯事故,輕則設備損壞,重則人員傷亡。因此,使堅硬頂板提前垮落,從而避免頂板事故及瓦斯事故的發(fā)生得到了人們的高度重視。本文研究了采用深孔爆破技術對堅硬頂板進行預裂使其提前垮落的理論與技術,對深孔爆破巖石破碎基礎理論進行了探討,利用ANSYS/LSDYNA和UDEC軟件分別對巖石爆破裂隙擴展和頂板初次斷裂步距進行了模擬分析,并以大陽煤礦3404綜放工作面為工程背景,設計和實施了爆破方案,并對深孔爆破預裂頂板改善綜放面初采期頂板初次來壓和瓦斯治理效果進行了實測分析。得出了以下主要結論:(1)確定了巖石爆破的相關參數。通過理論計算,得出巖石爆破形成的破碎區(qū)半徑為38.5cm,裂隙區(qū)半徑為195cm。利用ANSYS/LS-DYNA3D軟件對巖石爆破后的裂隙擴展進行了數值模擬,得出巖石爆破形成粉碎區(qū)半徑為39.5cm,裂隙區(qū)半徑約為185cm。數值模擬結果同理論計算結果基本一致。(2)深孔爆破使頂板由固支梁結構變?yōu)閼冶哿航Y構,使頂板初次垮落步距減小。利用UDEC數值軟件,對頂板在預裂條件下和非預裂條件下的初次垮落步距進行了模擬,結果表明:預裂爆破使頂煤的初次垮落步距減小了6.0m,直接頂初次垮落步距減小了9.6m,老頂初次來壓步距減小了12.0m。(3)同一鉆孔爆破前后進行窺視,爆破前鉆孔壁比較完整,爆破后鉆孔壁出現(xiàn)了較多的裂縫,證明爆破對頂板巖石起到了有效的預裂作用。(4)現(xiàn)場實測表明,與未進行預裂措施的3303工作面相比,3404綜放面頂煤初次垮落步距和老頂初次來壓步距分別提前了8m和11m;初次來壓期間支架動載系數最小1.03、最大1.26,平均1.10。說明采取頂板預裂后,頂板初次來壓期間,采場支護是安全的。(5)深孔預裂爆破能有效預防工作面初采期間瓦斯超限問題。初采前對頂板進行爆破預裂,使頂煤煤巖體內原生裂隙擴張,并產生新的裂隙,破壞了頂板的完整性,明顯減小了頂煤的初次垮落和老頂的初次來壓步距,減小了采空區(qū)的懸頂面積,使頂層輔助回風巷提前發(fā)揮作用,有利于工作面通風管理,降低了工作面和上隅角瓦斯?jié)舛?確保了初采期間工作面的安全生產。(6)對高位鉆孔瓦斯抽采濃度和抽采純量的變化進行了實測分析,結果表明:高位鉆孔瓦斯抽采濃度和抽采純量的變化與頂板活動規(guī)律一致,說明預裂頂板使頂板巖層產生裂縫,并且老頂巖層提前斷裂來壓,導致大量瓦斯被高位鉆孔抽出是初采期間工作面和上隅角瓦斯?jié)舛冉档偷脑�因之一�?br/>[Abstract]:China is rich in coal resources, and there are more hard roof coal seams. The existence of thick and hard roof seriously threatens the safety production of coal mining face, especially during the initial mining period, the roof integrity is good, and it will not collapse itself in the short term, which makes the initial pressure step increase. Once the roof collapses in a large area gas gushes out of the goaf easily causing roof and gas accidents light equipment damage and heavy casualties. Therefore, people attach great importance to the prevention of roof accidents and gas accidents by making hard roof collapse ahead of time. In this paper, the theory and technology of using deep-hole blasting technology to pre-crack hard roof to make it collapse ahead of time are studied. The basic theory of rock fragmentation in deep-hole blasting is discussed. ANSYS/LSDYNA and UDEC software are used to simulate the crack expansion of rock blasting and the initial breakage distance of roof, and the blasting scheme is designed and implemented with the 3404 fully mechanized caving face of Danyang Coal Mine as the engineering background. The effect of pre-split roof by deep hole blasting on the initial roof pressure and gas control in the initial mining stage of fully mechanized caving face is analyzed. The main conclusions are as follows: 1) the relevant parameters of rock blasting are determined. By theoretical calculation, the radius of fracture zone and fracture zone of rock blasting are 38.5 cm and 195 cm respectively. The crack propagation after rock blasting is simulated by ANSYS/LS-DYNA3D software. It is concluded that the radius of rock blasting is 39.5 cm and the radius of crack area is about 185 cm. The numerical simulation results are in good agreement with the theoretical results.) Deep hole blasting changes the roof structure from a fixed beam structure to a cantilever beam structure and reduces the initial collapse step distance of the roof. Using UDEC software, the initial collapse distance of roof under pre-cracking and non-pre-cracking conditions is simulated. The results show that the first caving distance of top coal is reduced by 6.0 m, the first collapse distance of direct roof is reduced by 9.6 m, and the initial pressure step of main roof is decreased by 12.0 m.f3) the borehole wall is relatively complete before and after blasting. There are many cracks in the borehole wall after blasting, which proves that blasting has an effective pre-splitting effect on roof rock. Compared with the 3303 working face without pre-splitting measures, the first collapse distance of top coal and the first starting step of main roof of No. 3404 top-coal caving face were 8m and 11m earlier, respectively, and the minimum dynamic load coefficient of the support during the initial loading period was 1.03m, the maximum 1.26m, and the average 1.10m. It is shown that after pre-splitting of roof, the stope support is safe during the initial pressure period of roof, and the deep-hole pre-splitting blasting can effectively prevent the gas over-limit during the initial mining of the working face. Before the initial mining, the roof was pre-cracked by blasting, which made the primary cracks in the top coal and rock expand, and produced new cracks, which destroyed the integrity of the roof, and obviously reduced the initial collapse of the top coal and the initial pressure step of the main roof. The suspended roof area of the goaf is reduced, and the auxiliary return air roadway of the top floor is brought into play in advance, which is beneficial to the ventilation management of the working face and the gas concentration in the working face and the upper corner. The change of gas extraction concentration and extraction scalar quantity in high borehole is measured and analyzed. The results show that the change of gas extraction concentration and scalar quantity in high borehole is consistent with the law of roof movement. It is shown that the pre-crack roof makes the roof rock layer crack and the main roof rock strata break and pressure ahead of time, which results in a large amount of gas being extracted from the high hole is one of the reasons for the decrease of the gas concentration in the working face and the upper corner during the initial mining.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TD712;TD235.33

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