Study On Response Characteristics Of Resistance Of Gas-free Coal To Moisture Content During Water Permeability

Due to the implementation of hydraulic measures in the original state of the coal body,the water will have a seepage effect in the coal body,resulting in uneven distribution of water in the coal body,different water content in different parts,etc.,and it is necessary to find a reliable and simple one.The method of testing moisture Therefore,it is particularly important to carry out research on the water content of coal and to understand the proportion of water in the coal.This paper intends to investigate the response characteristics of resistivity to water content after gas absorption without gas.The resistivity measurement is used to determine the water content in coal.It lays a foundation for the study of the response characteristics of resistivity to moisture content in gas infiltration process,and provides a reference for the use of hydraulic measures to effectively control mine gas and ensure the safe production of minesIn this paper,the response characteristics of resistivity to water content in the process of infiltration of coal briquettes under different electrode diameters and different pressing loads are studied.The response characteristics of resistivity to water content in gas-free infiltration process are studied.Analysis,experimental testing and fitting calculations and analysis have achieved the following understanding(1)The resistivity method can be used to test the resistivity of coal moisture with time under different conditions,and its water content and resistivity have certain regularity during the continuous infiltration process;(2)Under the same pressing load and different water content,the resistivity changes with time and then decreases sharply and then decreases slowly,and finally reaches a stable trend,showing a similar trend of "L".The resistivity stability limit value decreases with the increase of water content,and the slope of the initial decrease of the resistivity of the briquette with large water content is larger than that of the water content;(3)Under the same water content and different pressing load conditions,the resistivity changes with time and then decreases sharply and then decreases slowly,and finally reaches a stable trend,showing a similar trend of "L".The resistivity stability limit value decreases with the increase of the pressing load,and the slope of the initial decrease of the resistivity of the briquette with a large pressing load is larger than the pressing load;(4)Using the origin software to fit the resistivity experimental data under different water content and different pressing load conditions,it is found that the relationship between the resistivity p and the time t accords with the function p=a-b*ct;(5)Under the same compression load conditions,the briquette resistivity limit decreases with increasing water content.The limit value p of the briquette resistivity and the water content w satisfy the relationship of p=abW+c,and the fitting formula can better reflect the variation of resistivity limit value and water content;(6)The briquette resistivity limit decreases with increasing compressive load at the same moisture content.The limit value p of the resistivity of the briquette and the pressing load σ satisfy the relationship of p=abσ+c,and the fitting formula can better reflect the variation of the resistivity limit value and the pressing load;(7)It is considered that under the same pressing load and different water content conditions,the briquette resistivity limit value measured by the briquette electrode piece diameter of 30 mm is larger than that.The diameter of the briquette resistivity measured by the electrode piece diameter of 30 mm is also larger than the briquette piece diameter of 50 mm;(8)The briquette resistivity limit measured by the briquettes with a diameter of 30 mm and the diameter of the briquette electrode is 50 mm.The diameter of the briquette resistivity measured by the electrode piece diameter of 30 mm is also larger than that of the briquette electrode piece by 50 mm;(9)The resistivity of the coal body can be tested for different diameter electrode sheets.Under the same conditions,the resistivity of the different diameter electrode sheets is different.This is because the two plates of the resistivity and the connected conductive solution are generated under the action of the applied electric field.Current,and the magnitude of the current is related to the conductivity of the solution and the size of the electrode.Under the same conductivity of the solution,the larger the diameter of the electrode,the more conductive ions are simultaneously contacted on the electrode,and the current is higher.It is bigger.Therefore,under the same pressing load and the same water content,the electrode sheet having a diameter of 50 mm is less than 30 mm in diameter.In order to facilitate the later research,the electrode resist should be tested with the same specifications as the previous experiment.