受矿井采掘布局影响，相邻两工作面存在相向回采现象。在回采过程中，煤柱受到叠加采动应力影响，极易导致煤柱产生裂隙形成漏风通道，使得采空区内部漏风量增大且流场紊乱，容易形成复合采空区。复合采空区一旦发生煤自燃，氧化产生的各种有毒有害气体会在复合采空区内不断流动，使火区位置难以判定，治理难度增加。本文以陕北某矿2206工作面与其邻近煤矿2201工作面相向回采为研究背景，通过实验研究、数值模拟研究煤自燃特性及极限参数、煤柱裂隙演化规律，在此基础上建立复合采空区煤自燃模型，研究复合采空区煤自燃危险区域，最后根据上述研究成果提出邻近工作面相向开煤自燃防治措施，达到有效避免煤自燃灾害发生的目的，获得如下研究成果：

（1）采用程序升温实验研究煤自燃特性参数，结果表明煤样耗氧速率、气体生成速率和放热强度均随温度升高而指数增长，并结合现场实际情况，确定CO、C₂H₄和C₃H₈作为监测指标气体；确定采空区上限漏风强度为0.0015m/s，下限氧浓度6.9%，为煤自燃危险区域的判断提供基础参数。

（2）利用FLAC^3D模拟研究邻近工作面相向回采时煤柱应力位移分布特征及裂隙演化规律，发现当工作面相距120m时，两工作面采动应力开始相互影响；当工作面相距40m时，两工作面采动应力影响显著；当工作面相遇时，两工作面采动应力相互影响程度进一步增加，但煤柱裂隙发育程度仍较小。当两工作面相遇后煤柱受到两侧叠加的采空区覆岩压力，同时受到二次采动影响，并且随着工作面推进，采空区覆岩压力增大，裂隙发育程度增大，当两工作面相错80m时，相错区域的煤柱应力位移大幅增加，煤柱变形程度增大，裂隙发育程度加剧。

（3）基于复合采空区空间分布特征，结合计算流体力学理论建立了复合采空区数值模型，掌握相向回采工作面复合采空区的氧气浓度分布规律，并研究了煤柱孔隙率及两工作面压差对复合采空区的氧气分布影响规律。结果表明随着煤柱孔隙率及工作面压差的增大，复合采空区氧化带范围增大。

（4）根据前文研究结果，结合现场实际情况，确定邻近工作面相向回采复合采空区煤自燃发火影响因素，针对不同回采阶段的复合采空区煤自燃危险区域，优化回采方案，把漏风堵漏、调压控风、采空区覆盖隔氧及惰化降氧等多种煤自燃防控技术相结合优化煤自燃综合防控技术，并构建了邻近工作面相向回采复合采空区煤自燃防控体系，有效控制了邻近工作面相向回采复合采空区煤自燃问题。

Influenced by the mining layout of the mine, two adjacent working faces are back-mined in opposite directions. In the back mining process, the coal column is affected by the superimposed mining stress, which will easily lead to the formation of air leakage channels in the coal column, making the air leakage inside the mining area increase and the flow field disorderly, which will easily form the compound mining area. Once coal spontaneous combustion occurs in the compound mining area, various toxic and harmful gases produced by oxidation will flow continuously in the compound mining area, making it difficult to determine the location of the fire area and increasing the difficulty of management. This paper takes 2206 working face of a mine in northern Shaanxi Province and its neighboring coal mine 2201 working face of the opposite direction back mining as the research background, through experimental research, numerical simulation research coal spontaneous combustion characteristics and limit parameters, coal column fissure evolution law, on this basis to establish the composite mining area coal spontaneous combustion model, research composite mining area coal spontaneous combustion risk area, and finally based on the above research results to put forward the neighboring working face of the opposite direction open coal spontaneous combustion prevention measures In order to achieve the purpose of effectively avoiding the occurrence of coal spontaneous combustion disaster, the following research results were obtained:

(1) Using the programmed warming experiment to study the parameters of coal spontaneous combustion characteristics, the results show that the oxygen consumption rate, gas generation rate and exothermic intensity of coal samples increase exponentially with the increase of temperature, and combined with the actual situation on site, CO, C₂H₄ and C₃H₈ are determined as the monitoring index gases; the upper limit of air leakage intensity in the mining area is determined to be 0.0015m/s, and the lower limit of oxygen concentration is 6.9%, which provides the basic parameters for the coal spontaneous combustion risk area provide basic parameters for the judgment of coal spontaneous combustion risk area.

(2) Using FLAC^3D simulation to study the characteristics of coal column stress displacement distribution and fissure evolution law when the neighboring working faces are retrieved in opposite directions, it is found that when the working faces are 120m apart, the mining stresses of the two working faces start to influence each other; when the working faces are 40m apart, the mining stresses of the two working faces affect each other significantly; when the working faces meet, the degree of mutual influence of the mining stresses of the two working faces increases further, but the coal column fissure The development degree is still small. When the two working faces meet, the coal column is subjected to the overburden pressure of the mining area superimposed on both sides, and is also affected by secondary mining, and as the working face advances, the overburden pressure of the mining area increases, and the degree of fissure development increases, and when the two working faces are staggered by 80m, the stress displacement of the coal column in the staggered area increases significantly, the deformation of the coal column increases, and the degree of fissure development intensifies.

(3) Based on the spatial distribution characteristics of the composite mining area, a numerical model of the composite mining area was established based on the theory of computational fluid dynamics to grasp the distribution law of oxygen concentration in the composite mining area of the phase back mining face, and the influence law of coal column porosity and pressure difference between the two working faces on the oxygen distribution in the composite mining area was studied. The results show that with the increase of porosity of coal column and pressure difference of working face, the range of oxidation zone in composite mining area increases.

(4) According to the results of the previous study, combined with the actual situation of the site, the factors influencing the spontaneous combustion of coal in the composite mining area of the adjacent working face and the risk area of spontaneous combustion of coal in the composite mining area at different stages of recovery are determined, the recovery plan is optimized, and various coal spontaneous combustion prevention and control techniques, such as air leakage plugging, pressure control air, oxygen barrier in the mining area cover and inerting oxygen reduction, are combined to optimize the comprehensive coal spontaneous combustion prevention and control technology, and the adjacent.

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