露天矿遗煤区地表CO_2通量变化规律测试分析

Test and analysis of surface CO_2 flux variation in opencast coal mining area

探索了通过采空区上部地表CO_2通量变化判定遗煤自燃状态的实验理论及方法,并根据地表和大气间的扩散原理,采用自主研发的土壤气体监测系统,对采空区上覆地表CO_2通量进行了连续测定。研究结果表明:采空区遗煤自燃对其上覆地表CO_2通量变化有较大影响;采空区年限及遗煤氧化自热程度影响地表CO_2通量的大小;自燃带地表CO_2通量明显大于窒息带。地表CO_2通量变化能反映采空区漏风量对遗煤自燃的影响;研究地表CO_2通量变化规律,能够帮助了解采空区遗煤自燃火区的发育方向、范围等相关问题。研究对废弃矿井采空区地表环境评估,废弃矿井采空区遗煤氧化自燃的危险性评估以及浅埋煤层氧化自燃发火进行程度的探测具有重要意义。

The experimental theory and method to judge the spontaneous combustion state of residual coal by measuring the change of CO2 flux on the upper ground surface of goaf were explored,and according to the diffusion principles of the ground surface and the atmosphere,the CO2 flux on the overlying ground surface of goaf was continuously measured by using the selfdeveloped soil gas monitoring system. The results showed that the spontaneous combustion of residual coal in the goaf had relatively large influence on the change of CO2 flux on the overlying ground surface. The life of goaf and the degree of oxidation and self-heating of the residual coal would influence the amount of CO2 flux on the ground surface,and the CO2 flux on the ground surface in the spontaneous combustion zone was obviously larger than that in the suffocation zone. The change of CO2 flux on the ground surface can reflect the influence of air leakage in goaf on the spontaneous combustion of residual coal. The study on the change laws of CO2 flux on the ground surface is helpful to understand the development direction,range and other related problems of the spontaneous combustion area of the residual coal in goaf. This study has important significance for the ground surface environmental assessment of goaf,the risk assessment on the oxidation and spontaneous combustion of residual coal in goaf,and the detection on the degree of oxidation and spontaneous combustion in the shallow coal seam.