随着我国煤炭开采强度和深度的不断加大，采空区遗煤量增多。地下含水层受到采动破坏逐步聚积到采空区，造成采空区大面积积水。根据《煤矿安全规程》规定，进行采掘作业时必须对受到影响的相邻采空区积水进行疏放。采空区遗煤经过水浸泡孔隙发育，疏放水后，煤体与氧气的接触面积显著加大，自燃危险性显著增强。主要研究成果如下：
通过氮气吸附和傅里叶红外光谱实验，研究了原煤和浸水煤孔隙结构以及官能团的变化。随着煤在蒸馏水和矿井水中浸水时间的增加，其平均孔径逐渐增大，比表面积和孔体积都呈下降趋势。具体表现为原煤的平均孔径是10.08 nm，而在矿井水浸水60天的平均孔径是12.14 nm，增加了20.4%；比表面积和孔体积与原煤相比分别降低了27.1%和12.2%。此外，这种变化增加了煤与氧气的接触面积，从而更有利于煤的氧化反应进行。
通过同步热分析和程序升温实验，研究了原煤和浸水煤的自燃特性。研究表明，浸水煤的特征温度和最大放热速率温度相对于原煤都有所提前。随着温度的升高，热量释放逐渐增多。采用FWO、KAS和Kissinger三种动力学计算方法得出样品的表观活化能，发现浸水煤的平均表观活化能均低于原煤，在矿井水浸水60天表现最为明显，分别降低了24.88 kJ mol-1、7.39 kJ mol-1、20.7 kJ mol-1，即随着浸水时间的增加，煤的自燃倾向性呈增大趋势。程序升温实验结果表明，浸水煤氧化过程中氧气消耗量高于原煤且释放的CO、CO2、CH4和C2H4气体浓度明显高于原煤。浸水后的煤样氧化活性更高，更容易发生自燃。
通过证据信念函数和频率比模型研究官能团与放热量之间的关联性。结果表明，原煤和浸水煤在氧化条件下，不同官能团与放热量之间的关联度随阶段变化而有所差异，这说明煤的放热特性是多官能团共同作用的产物。而灰色关联度分析结果表明，原煤和浸水煤的表观活化能与官能团的关系按显著性降序排列为：游离羟基>C=O>-COOH>-CH3>-CH2>CH>C=C>分子内氢键，研究结果为浸水煤自燃防控提供基础。

With the increasing intensity and depth of coal mining in China, the amount of residual coal in goaf has increased. The underground aquifer is gradually accumulated to the goaf by mining damage, resulting in a large area of water accumulation in the goaf. According to the Coal Mine Safety Regulations, it is necessary to drain the affected adjacent goaf water during mining operations. The residual coal in the goaf is developed through water soaking pores. After water drainage, the contact area between coal and oxygen is significantly increased, and the risk of spontaneous combustion is significantly enhanced. The main results show that:
The changes of pore structure and functional groups of raw coal and soaked coal were studied by nitrogen adsorption and Fourier transform infrared spectroscopy. With the increase of soaking time of coal in distilled water and mine water, the average pore size increases gradually, and the specific surface area and pore volume decrease. The specific performance is that the average pore size of raw coal is 10.08 nm, while the average pore size of 60 days in mine water immersion is 12.14 nm, an increase of 20.4 %; the specific surface area and pore volume decreased by 27.1 % and 12.2 %, respectively, compared with raw coal. In addition, this change increases the contact area between coal and oxygen, which is more conducive to the oxidation reaction of coal.

The spontaneous combustion characteristics of raw coal and water-soaked coal were studied by simultaneous thermal analysis and temperature programmed experiments. The results show that the characteristic temperature and the maximum heat release rate temperature of soaked coal are earlier than those of raw coal. As the temperature increases, the heat release gradually increases. The apparent activation energy of the samples was obtained by FWO, KAS and Kissinger three kinetic calculation methods. It was found that the average apparent activation energy of the soaked coal was lower than that of the raw coal, and the performance was the most obvious in the 60 days of mine water immersion, which was reduced by 24.88 kJ mol^-1,7.39 kJ mol^-1 and 20.7 kJ mol^-1, respectively. With the increase of immersion time, the spontaneous combustion tendency of coal showed an increasing trend. The results of temperature-programmed experiments show that the oxygen consumption during the oxidation of soaked coal is higher than that of raw coal and the concentrations of CO, CO₂, CH₄ and C₂H₄ released are significantly higher than those of raw coal. The coal sample after soaking has higher oxidation activity and is more prone to spontaneous combustion.

The correlation between functional groups and heat release was studied by evidence belief function and frequency ratio model. The results show that the correlation degree between different functional groups and heat release varies with the change of stage under the oxidation condition of raw coal and water-immersed coal, which indicates that the heat release characteristics of coal are the product of the interaction of multi-functional groups. The results of grey correlation analysis show that the relationship between apparent activation energy and functional groups of raw coal and soaked coal is in a significant descending order: free hydroxyl group > C=O > -COOH > -CH₃ > -CH₂ > CH > C=C > intramolecular hydrogen bond. The research results provide a basis for the prevention and control of spontaneous combustion of soaked coal.