The Analysis Of Main Influence Factors And Correction Of Radon Concentration In Shallow Surface Of Ulanqab

Along with the progress of the society,the consumption of energy is still high.Coal occupies a very important position among the primary energy consumption.But the coal at the edge and many legacy coal pillar all be abandoned under the ground in a large number of coal enterprises.Because coal is non-renewable resources,in order to reduce the waste,to increase the efficient use of energy,the underground coal gasification with its high safety,less investment,high efficiency and less pollution and so on attract the attention of the countries all over the world as a new technology for modern coal mining.The key of realizing the industrialization lies in the monitoring of gasification combustion work surface.Through compare of gravity prospecting,magnetic prospecting,electrical prospecting,seismic prospecting and radioactive prospecting,we prefer to choose the active carbon measuring radon technology which belongs to the radioactive prospecting method.We use this technology to detect the burning working surface of the underground coal gasification in Ulanchap.In order to fully reflect the change trend of Rn about the initial distribution,the implementation of pressure through gasification channel and after the ignition in this area.We need to correctly recognize the distribution and the change trend of background of Rn.But in the lointerference ng-term monitoring,it is have to involve a lot of factors,such as the well-known changes in temperature,humidity,etc.This thesis is supported by Chinese "863" project,called "the key technique of gasification industrialization of underground coal.We research and improve the all-weather radon gas sampling device based on the stability and consistency of radon measurement instrument.The sampling devices ensure the hole depth and the sample conditions are basically identical at the same time.On the premise of reduce the influencing factors of these systems,we carefully analysis the long-term regularity of Rn gas in natural condition under different geological condition in the shallow surface.After correcting every influence factor,we setting "points" synchronize with the gasification field to correct the influence of weather;By comparing the radon gas distribution of the original state through different medium,we put forward r correction coefficient for different overlying medium;Through embedment on the same length all-weather measuring radon sampling device in the hole,we eliminate the influence of depth to the radon value.By analyzing and correcting the main influence factors which result in the change of radon concentration,how to determine the location and area of radon anomalies is also appeared especially important.Radon concentration distribution has the characteristics of randomness,uncertainty and regional,traditional mathematical methods have been difficult to accurately describe the spatial distribution regularity of elements in the earth.This paper uses trend surface analysis method and the total-content of fractal theory to determine the limit of radon anomaly,so as to determine the influence area and scope of the high temperature which produced by the underground coal gasification.Fractal method can descript the space irregular shape more effective,and the deterministic nature of this irregular shape can be characterized with fractal dimension values;Trend surface analysis method can not only learn the overall distribution of state of the radon value,but also separate the local anomaly from the whole.Compared with the traditional method to determine the lower limit of anomalies,the two methods not only can simulate the spatial distribution characteristics of the radon concentration in the region effectively,but also can retain the original effectived information,and can distinguished the radon value range between normal and abnormal more reasonable.In order to highlight useful anomaly in the low-level radioactive ?i background more effectively,under the existing technical condition,we hope that through to suppress interference factors of radon background field,try our best to reduce the impact of the external random conditions to the lowest.The content of this study pointed out not only with the time,the type of the medium depth radon original natural distribution state is different,but also solved the elimination of meteorological factors,in the case of long-term monitoring of medium depth,and proposed the to identify outliers lower limit in the conditions of low-level radioactive.We provided a worthy reference in such areas ideas for geological survey tasks.