煤峪口矿近距离煤层复合采空区自燃三带判定研究

发布时间：2018-12-13 17:34

【摘要】：我国大部分煤层都存在自燃现象,尤其是随着综采放顶煤技术的成熟及推广应用,由于其一般情况下所开采煤层厚度较大,当工作面回采过后,进风巷道和回风巷道顶煤随着顶板的塌陷落入采空区,导致采空区内部进回风巷道位置遗煤量较多,容易与氧气接触氧化升温,引起自然发火,酿成火灾事故。大多数矿井的煤层是成群的,而不是单独存在的。当对近距离煤层群其中一个煤层进行开采时,临近煤层受采动影响,一方面原煤层群具备的应力平衡状态被破坏,导致应力在煤层岩体内部重新分配,煤层间形成大量的裂隙,漏风情况复杂化;另一方面,当开采下层煤时,在受到下层煤采动影响后,岩层塌陷,上覆采空区遗煤进一步破碎,上下两层煤采空区将沟通,形成复合采空区。复合采空区中的遗煤分布规律与漏风情况的复杂化使其与单层采空区的自燃危险区域有很大区别。本文以煤峪口矿81004工作面为研究背景,从近距离煤层群开采和复合采空区注氮的特点出发,对其所形成的复合采空区的自燃三带进行划分。首先,从81004工作面近距离煤层的特点出发,结合煤自燃发火机理、近距离煤层特点与工作面实际情况对其进行理论分析;然后,通过自然发火试验台,测定了81004工作面上覆煤层煤样的耗氧速度、极限浮煤厚度、放热强度及不同浮煤厚度下的上限漏风强度与下限氧浓度等自燃特性参数;最后,根据复合采空区的相关参数、煤自燃特性参数与相关理论知识,建立了近距离煤层复合采空区的数学模型,设定相关参数,分别模拟了注氮和不注氮条件下复合采空区的氧气浓度等值线及漏风强度等值线图,并结合现场测得数据,根据采空区自燃危险区域判定理论,对注氮和不注氮两种条件下的复合采空区三带进行分析研究。由实验模拟所得的实际情况下最短自然发火期与氧化升温带的范围大小,计算出81004工作面的最小安全推进速度,以保证其上覆工作面采空区遗煤不会自燃。
[Abstract]:There is spontaneous combustion in most coal seams in our country, especially with the maturation and popularization of fully mechanized caving coal mining technology, because of the large thickness of coal seams in general, when the mining face after mining, The top coal of the entry and return air roadway falls into the goaf with the collapse of the roof, which results in more coal left in the entry and return air roadway position in the goaf, and it is easy to oxidize and heat up with oxygen, which will cause spontaneous combustion and lead to fire accident. Most coal seams in mines are clustered rather than alone. When mining one of the coal seams in close distance, the near coal seam is affected by mining movement. On the one hand, the stress balance state of the raw coal seam group is destroyed, which results in the stress redistribution in the coal seam rock mass, and a large number of cracks are formed between the coal seams. Complicated air leakage; On the other hand, when mining the lower coal, the rock layer collapses after being affected by the lower coal mining, the coal left over the overlying goaf is further broken, and the upper and lower coal goaf will communicate and form the compound goaf. The distribution of coal in the compound goaf and the complication of the air leakage make it very different from the danger area of spontaneous combustion in the single-layer goaf. In this paper, based on the research background of No. 81004 face in Meiyukou Coal Mine, based on the characteristics of close distance coal seam group mining and nitrogen injection in compound goaf, the three zones of spontaneous combustion of compound goaf are divided into three zones. First of all, according to the characteristics of coal seam in 81004 working face, combined with the mechanism of spontaneous combustion of coal, the characteristics of coal seam in close distance and the actual situation of coal face are analyzed theoretically. Then, the spontaneous combustion characteristics such as oxygen consumption velocity, limit floating coal thickness, exothermic intensity and upper limit air leakage intensity and lower limit oxygen concentration under different floating coal thickness were measured by natural combustion test bench. Finally, according to the related parameters of compound goaf, coal spontaneous combustion characteristic parameters and relevant theoretical knowledge, the mathematical model of composite goaf in short distance coal seam is established, and the related parameters are set up. The contours of oxygen concentration and air leakage intensity in the compound goaf under the condition of nitrogen injection and no nitrogen injection are simulated, respectively. Combined with the field data, the theory of judging the dangerous area of spontaneous combustion in goaf is presented. The three zones of compound goaf under two conditions of nitrogen injection and no nitrogen injection were analyzed and studied. The shortest spontaneous combustion period and the range of oxidized heating zone are obtained from the experimental simulation, and the minimum safe advancing speed of 81004 working face is calculated, so as to ensure that the coal left in the goaf of the overlying face will not be self-ignited.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD752.2

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