无井式煤炭地下气化导水裂缝带高度发育规律及特殊关键部位破断机理

Underground coal mining without shaft style is trend of the gasification development; meanwhile it faces the risk of roof aquifer water rushing into gasifier, which affects thermal efficient or even destroys the gasifier. It is that the high temperature and pressure environment in gasifier makes completely different between the developments of water flowing fissure in roof strata and the way of traditional underground coal mining. Therefore, the research on height of water conducted zone and failure mechanism of special part in no-shaft UCG has important theoretical and practical significance. Based on the results of core drilling and similar simulation test; the mechanical properties of roof mudstone in gasifier under different temperature and pressure are studied, which determines the critical temperature of mudstone sintering. The variation of mudstone and mudstone combination solid of axial strain, lateral strain and volumetric strain with temperature is analyzed. Researching on the modification and sintering characteristics of mud and mud combination, the index system which affects the overburden failure and water conductivity in gasifier is built. The relationship between overburden failures in gasifier and different stages (three zones in temperature field), gasification pressure, gasification depth, gasification coal seam thickness and the gasifier length is analyzed. Based on the experimental data of ground observation, it shows that the development process of water conducted zone in weak overburden from the beginning to the maximum height. The development law of water flowing fractured zone in different stages (three zones in temperature field) is determined. By using RFPA, it conducts the numerical simulation of mechanical failure on the intake and other special parts of the pit underground gasification. Based on analyzing the continuous mechanical failure of the process time-varying spatial and temporal effects of this special key parts of the underground gasification process, the breaking small-scale relational model of the intake flow and special key parts is built. The differentiation temperature of different lithology materials is determined and the relationship between the temperature and the strength weakening of mudstone and mudstone combination is analyzed. Combined with similar material simulation, the mechanical failure criterion of special key parts in the pit underground gasification is put forwards.

无井式燃气炉的高温高压环境使得顶板导水裂缝发育与传统井工采煤方式完全不同，因此研究无井式煤炭地下气化导水裂缝带高度发育规律有重要的理论和实际意义。依据钻孔取芯和相似模拟实验结果，研究气化炉顶板泥岩在不同温度和压力下的力学性质，确定泥岩烧结的临界温度；分析泥岩及泥岩组合体的轴向应变、侧向应变和体积应变随温度的变化规律；研究高温条件下泥岩及泥岩组合体的改性和烧结特征；构建影响气化炉覆岩破坏及其导水性的指标体系；依据地面观测试验资料软弱覆岩导水裂缝带从开始形成到最大发育高度随气化阶段的发育过程，确定不同气化阶段导水裂缝带的发育规律。利用RFPA对无井式地下气化的进气等特殊部位的力学失效进进行数值模拟，分析研究连续地下气化进程中此特殊关键部位力学失效过程的时变空间和时间效应；构建进气流量和特殊关键部位泥岩及泥岩组合体强度弱化和温度的关系；提出无井式地下气化特殊关键部位力学力学失效的判据。

无井式燃气炉的高温高压环境使得顶板导水裂缝发育与传统井工采煤方式完全不同，因此研究无井式煤炭地下气化导水裂缝带高度发育规律有重要的理论和实际意义。依据钻孔取芯和相似模拟实验结果，研究气化炉顶板泥岩在不同温度和压力下的力学性质，确定泥岩烧结的临界温度；分析泥岩及泥岩组合体的轴向应变、侧向应变和体积应变随温度的变化规律；研究高温条件下泥岩及泥岩组合体的改性和烧结特征；构建影响气化炉覆岩破坏及其导水性的指标体系；依据地面观测试验资料软弱覆岩导水裂缝带从开始形成到最大发育高度随气化阶段的发育过程，确定不同气化阶段导水裂缝带的发育规律。对无井式地下气化的进气等特殊部位的力学失效进进行数值模拟，分析研究连续地下气化进程中此特殊关键部位力学失效过程的时变空间和时间效应；构建进气流量和特殊关键部位泥岩及泥岩组合体强度弱化和温度的关系；提出无井式地下气化特殊关键部位力学力学失效的判据。