Radon Concentration Distribution And Zxperimental Study In Shallow Surface Of Ulanqab

The ground radon concentration detection,a measuring method,was widely used in mineral exploration,structural research,underground goaf probing,earthquake monitoring and environmental protection and so on.However,collection of radon concentration in the shallow earth surface is key to the accurately radon measurement.Radon concentration in the shallow earth surface varies with temperature,humidity,pressure and season changes,but the surface medium was one of the factors affecting the radon concentration.Therefore,using a static,cumulative radon measurement method to study radon concentration distribution characteristics in rock,soil and soil rock mixture region had a practical significance.The paper was based on collecting of a large number of data,used the UulanQabu radon detection technique to detect underground gasifying furnace combustion state monitoring(863 projects)and adopted the active carbon radon measurement method to study radon concentration varying with depth,season and the optimal sampling depth to characteristics of underground gasification furnace area surface with pure soil and basalt outcropping in UulanQabu.With the requirement of all-weather monitoring the underground fire area,the author preliminary made an all-weather underground sampling device for static,accumulated active carbon radon measurement.The result was that whether the pure soil or basalt region,in late spring,early fall and summer,shallow surface was not frozen(no permafrost),radon density increased with the depth,when in the certain depth,it turned to stable state.But when the shallow surface was frozen(permafrost),radon density didn,t increased but decreased with the depth and the range was not obvious,which implied that the permafrost had heavy influence on the radon migration,the radon concentration varied with the season as following:?In the pure soil area,didn' t change with the depth during 20cm and 40cm;changed great in the winter and spring during 60?100cm and the value was high,however it was close to the average value;the radon concentration was the highest in the summer and the lowest in autumn.? In the basalt area,radon concentration didn't not change with the seasons during 20cm;the radon concentration was highest in the spring and lower in the winter and autumn during 40cm;higher in the winter and spring but the lowest in the autumn during 60?80cm;higher in the spring and summer but lower in autumn during 100?200cm.The paper made a further research on radon sampling depth and got the result that the best buried depth of active carbon adsorption instrument was 40cm.In order to assure the conformity of radon measurement conditions,the author made an all-weather underground measuring radon sampling device in the experiment and made a preliminary experiment,the result showed that the device was useful.The above research results not only played a role of safeguarding the gasifier combustion state of the ground floor of radon monitoring in UulanQabu and drawing accurately radon measurements in other regions which had certain practical value on better solving the geological problem.