【作者】 刘健；

【导师】 刘泽功；

【作者基本信息】 安徽理工大学 ， 安全技术及工程， 2008， 博士

【摘要】 在煤矿开采过程中,瓦斯灾害一直是威胁煤矿安全生产的主要灾害之一。虽然国内外学者在瓦斯治理方面进行了大量的研究工作,取得了一定的成果,对防治重大的瓦斯灾害事故起到了重要作用,但还没有从根本上完全防止瓦斯灾害事故的发生。目前,煤层瓦斯抽采措施被认为是预防瓦斯灾害最有效的方法之一,但是随着煤层开采深度的增加,煤层瓦斯含量增高、压力增大,煤层透气性小,从而严重影响了煤层瓦斯的抽采率和瓦斯抽采效果。因此,提高低透气性高瓦斯煤层的透气性获得较高的提高瓦斯抽采率已成为确保煤矿安全生产,实现煤矿安全高效生产的一个途径。我国的绝大多数煤田均为低透气性高瓦斯煤层,开展低透气性高瓦斯煤层增透技术和抽采瓦斯研究对于预防和消除煤与瓦斯突出等瓦斯灾害的发生具有重要的社会价值和经济效益。本文在前人研究成果的基础上,应用理论分析、实验研究、数值模拟和现场试验等方法研究了深孔预裂爆破技术对低透气性高瓦斯煤层增透提高煤层瓦斯抽采技术。首先分析了煤体结构和孔隙特性,总结出了孔隙—裂隙所形成的巨大网络是瓦斯运移通道,而瓦斯运移量的多少与煤岩渗透性和煤体破坏的力学性能等因素密切相关。通过煤体瓦斯流动特性的研究,为寻求低透气性高瓦斯煤层瓦斯治理措施,防治瓦斯灾害的发生提供了有力的理论依据。其次分析了深孔预裂爆破技术对低透气性高瓦斯煤层的作用机理,得出了炸药爆炸后,爆轰应力波和爆生气体作用是煤体介质大量裂隙生成的主要因素,并使爆破孔周边煤体产生径向“之”字形交叉裂隙网。控制孔为爆破提供了大量的辅助自由面,大大增加了裂隙区的范围,同时研究表明,煤体瓦斯压力对煤体裂隙的发育起促进作用;通过深孔预裂爆破对低透气性高瓦斯煤层增透的作用机理分析,表明深孔预裂爆破技术使煤体裂隙增多,透气性提高,应力重新分布,有利于煤体瓦斯抽采,使煤体瓦斯含量降低,瓦斯压力下降,从而有效消除和预防瓦斯灾害的发生。为了配合低透气性高瓦斯煤层深孔预裂爆破,选用合适的药管,并对药管性能进行了大量的实验研究,研究结果表明:其药管和炸药具有低速、抗阻燃、抗静电和防水性,传爆性能可靠。同时对药管进行多种介质松动模拟试验,得出药管对土壤、岩石和煤体的松动效果明显,对土壤和煤体的松动半径在4m左右,对岩石的松动半径超过2m,其传爆距离超过50m,对低透气性煤层实施深孔爆破具有良好的增透作用。建立低透气性高瓦斯煤层深孔预裂爆破卸压增透不同布孔形式的数学模型,借助Ansys/Ls-Dyna软件进行数值模拟,得出了当两爆破孔间距为6～7m时,两爆破孔间煤体中可以产生足够数量相互沟通的裂隙,此时煤体所承受的地应力小于原始地应力,使其处于卸压状态,增加了煤体的的透气性,为瓦斯抽采提供了瓦斯流动通道。应用低透气性高瓦斯煤层深孔预裂爆破增透的研究成果,在低透气性高瓦斯综采工作面、石门揭煤和巷道掘进中进行深孔预裂爆破煤层卸压增透,并抽出了大量的高浓度瓦斯,为实现煤矿安全高效开采提供了有效的技术途径。更多还原

【Abstract】 In the process of coal mining, gas hazard is always one of the main hazards which threat safety mining production in coal mine. Domestic and foreign scholars had done lots of work on controlling gas hazards and accomplished some achievements, but still can not completely avoid gas disasters fundamentally. At present, measures of pumping and extracting gas from coal seams are considered as one of effective methods controlling gas hazard. But as the increasing of mining depth, gas pressure and amount are becoming higher, permeability of coal seams becoming lower. These limited the rate of pumping and extracting gas and its effect severely. Therefore, increasing permeability of low permeable coal seams is a method to increase gas pumping and extracting rate to make mining production safe and improve efficiency. Most of coal field in our country are coal seams of low permeable and high gas occurrence, developing study on pressure relief and increasing permeability of coal seams to pump and extract gas of low permeable and high gas occurrence coal seams has important social value and economic benefit especially on preventing coal and gas outburst.On the basic of forerunner’ achievements, this paper researched deep-hole presplitting blast technology and its mechanism of preventing coal and gas outburst by applying theoretical analysis、experimental study、numerical simulation and test on workplaces. Coal body structure and pore characteristics are analyzed at first, and get the result that the huge network caused by pore and fracture is the channel of gas migration, and the amount of gas migration is closely related to permeability and mechanical performance of coal and rock. Studying on gas flow theory of coal seams provided a powerful basis to find effective measures controlling gas of low permeable and high gas occurrence coal seams and avoid occurrence of gas disaster. Secondly this paper researched deep-hole presplitting blast technology and its mechanism on low permeable and high gas occurrence coal seams. By analyzing, author get that explosive stress wave and explosive gas are the main factor to make coal medium’s fracture, and make a lot of fracture network by blasting hole. Controlling bores provide lots of auxiliary free surface to blasting holes, enlarged the range of fracture area. The research also showed that gas pressure of coal seams play a active role on enlarging of fracture area; this paper comprehensively analyzed the pressure relief and increasing permeability of coal seams mechanism of deep-hole presplitting and controlling blast, it shows that the technology increased the coal fracture and permeability of coal seams, redistribution of stress, beneficial to gas pumping and extracting of gas in coal seams, lower the gas amount and the gas pressure in coal body, so as to eliminate and prevent gas disaster. This research also selected equal explosive pipe, and test the performance by experiments. The result shows that the explosive pipe is low speed、flame retardant、antistatic and waterproof. Its performance of detonation transmission is reliable. Simulation experiment of explosive pipe explosion loosening effect in mediums was also done. It shows that the loosening effect is obvious in soil、coal and rock, loosening radius of soil and coal is about 4m, and it is more than 2m in rock, its detonation transmission distance is over 50m, so the explosive gave a good effect on increasing permeability of low permealility coal seams. This paper also established different holes arrangement mathematical models of low permeability high gas occurrence deep-hole presplitting blast. A numerical simulation was carried on by the software of Ansys/Ls-Dyna. It shows that when the distance between two blasting holes is 6~7m, coal body between two holes would generate enough throughout fractures, at this time ground stress on coal body is small than the initial ground stress, pressure on coal body are relived, permeability of coal is increased, channel for pumping and extracting gas are provided.Those research results above are applied on fully-mechanized face with the permeable and high gas occurrence、rock cross-cut coal uncovering and heading face. Blasting to relive ground stress and increase permeability in these workplace, and massive high-concentration gas was pumped and extracted. It shows the results providing some effective technical method for efficient and safe mining.更多还原