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为了得到条带地下气化开采覆岩移动下沉规律,以华亭煤炭地下气化为例,在气化过程傅里叶传热分析的基础上,建立含温度场的多层热弹性基础梁模型,分析温度场的存在对岩梁挠度的直接和间接影响,通过引入煤层烧变损伤因子并确定损伤范围,最后求得含损伤弹性基础的热弹性基础梁挠度解析解,并理论分析岩梁挠度、弯矩、剪力和载荷随时间的变化规律。结果表明:温度场的存在使岩梁在垂直方向和水平方向分别产生附加弯矩和热应力,其随时间在直接顶内呈先增大后减小,在老顶内呈一直增大趋势;岩梁挠度、弯矩、剪力和载荷基本都大于常温状态下的数值,且随覆岩热传导时间基本呈先增大后减小趋势。通过与现场实测下沉曲线的对比,说明该模型是合理的和符合实际的。
In order to obtain the law of underground subsidence and gas migration, the underground gasification of Huating coal was taken as an example. Based on the Fourier heat transfer analysis of gasification process, a multi-layer thermoelastic foundation beam model with temperature field was established , The direct and indirect influences of the temperature field on the deflection of the rock beam are analyzed. By introducing the damage factor of the coal layer and determining the damage range, the analytical solution of the deflection of the thermo-elastic foundation beam with damage elastic foundation is obtained and the deflection of the rock beam is theoretically analyzed , Bending moment, shear force and load change with time. The results show that the presence of temperature field causes additional bending moment and thermal stress in the vertical direction and the horizontal direction respectively. The bending moment first increases and then decreases with the time in the direct roof, and increases continuously in the roof. The deflection, moment, shear force and load of the rock girder are basically larger than those at normal temperature, and the heat conduction time of the rock cover first increases and then decreases. By comparing with the observed curve of in-situ settlement, the model is reasonable and realistic.