| The practical experience of various engineering construction shows that many engineering accidents and natural geological disasters are related to the form and content of water in the soil.Theoretical study of the changes in the mechanical and electrical properties of the soil caused by the change of the water content in the soil has great theoretical and practical significance,and will play an important technical support for the prevention of related engineering accidents in the future.At present,the research results on clay are fruitful,but the research on the electrochemical properties of kaolin and montmorillonite needs to be further in-depth.In this paper,through laboratory experiments,the soil samples of kaolin and montmorillonite were made,and the water content of kaolin was 20%,25%,30%,35%,and40%,and the water content was 30%,40%,60%,80%,and 90%of montmorillonite have undergone basic physical and mechanical properties test,dielectric constant test and electrochemical impedance spectroscopy test to study the influence of changes in water content on the physical and mechanical properties and electrochemical properties of kaolin and montmorillonite,And compare the results of several experiments to study the mechanical properties,dielectric constant and electrochemical parameters.There are certain rules.The main research results are as follows:(1)A pocket penetration test was carried out on samples of kaolin and montmorillonite with water content as a variable,and the law of strength changing with water content was obtained:as the water content in the soil increases,the strength of kaolin is first increasing and then decreasing,the strength of montmorillonite also increases first and then decreases,but the strength of montmorillonite is much greater than that of kaolin,and the corresponding water content when the strength of montmorillonite changes is greater than that when the strength of kaolin changes the water content.Due to the expansiveness of montmorillonite,it has a larger specific surface area than kaolin,and at the same time it has a stronger adsorption capacity.Therefore,the boundary water content of montmorillonite is relatively high.(2)Carry out the dielectric constant test of kaolin and montmorillonite with water content as a variable,and obtain the law of the influence of different water content in clay on its dielectric constant:As the water content of the soil sample increases,the water in the soil gradually replaces the air in the soil,the dielectric constants of kaolin and montmorillonite both increase.The critical water content of the change of the dielectric constant of the kaolin and montmorillonite samples is almost the same as the position of the water content corresponding to the peak of the penetration resistance of the sample,which proves that the change of the water content in the soil has an impact on the dielectric constant and physical mechanics of the soil.And there is a certain connection between the two,and the trend of change is similar.(3)Carried out the electrochemical impedance spectroscopy test of kaolin and montmorillonite under different water content,combined with the Nyquist diagram and Bode diagram to analyze the results:the electrochemical impedance spectroscopy of the two clays are non-quasi Randles circuit models,and the change trend is similar.Analyzing the law of equivalent circuit parameters of kaolin and montmorillonite,it is found that the solution resistance R_s gradually increases with the increase of water content,the charge transfer resistance R_t gradually decreases with the increase of water content,and the change law of the capacitance CPE-_T in contrast to the first two parameters.(4)Comprehensive analysis of the relationship between the physical and mechanical properties,dielectric constant and electrochemical parameters of kaolin and montmorillonite can draw:When the water content of the soil is greater than the plastic limit of the soil,the electrochemical parameters of kaolin and montmorillonite have a good correlation with the dielectric constant and penetration resistance,and the fitting formula can provide reference for related research. |
