Water Retention Characteristic Of Red Clay In Full Degree Of Saturation

It is aim at investigating the water retention characteristic in full degree of saturation of red clay, and expands the discussion for the influence of the variation of hydro-chemical environment on the soil water characteristic of red clay, and studies on a new method detecting water content in soil based on micro-electronic current coupling effect as well. To begin with, analysis the advantage and limitations, and the range of the pressure plate apparatus, vapor equilibrium method, filter paper method etc. A summary of research results in existence is given in this paper, the soil water characteristic range of 0-1000 kPa is determined by the pressure plate apparatus; suction test between 3200-365000 kPa is measured by vapor equilibrium method; suction experiment range of 1000kPa-10000 kPa is completed with filter paper method. The organic combination of these three methods can make a composite experiment scheme that is suitable for water retention characteristic test of full degree of saturation in red clay, shorten the test cycle, improve the efficiency and reduce the measurement error, innovate experiment method. The water retention characteristic of red clay influenced by pH in the pore water and concentration of electrolyte salt solution is tested by vapor equilibrium method. After a lot of experiments, combined with the clay mineral composition, physical properties and engineering features, and reference multiphase porous medium theory, analyzes the water retention characteristic of red clay and secondary red clay, discusses the influence law of water retention characteristic of soil influenced by pH in the pore water and concentration of electrolyte salt solution. The analysis of experimental results shows that soil water content and saturation in a same dry density reduce with the suction increasing, and the decreasing rate is reduced; the increasing solution concentration in pore water will promote soil water retention capacity, and it will provide technical support for the practical application and environmental disaster of red clay, also for the further development of the study on water retention capacity of red clay influenced by the variation of hydro-chemical environment. In view of the complicatedness and error in the determination of soil weight during the experimental process, puts forward a method and its device for water content detecting in soil based on micro-electronic current coupling effect at the same time.This research has obtained the following results:1、Soil water characteristic curve is determined for the red clay and secondary red clay of full saturation, obtained the results with practical value in project;2、Study on the influence law of the variation of hydro-chemical environment on the water retention characteristic of red clay, and analyse the influence mechanism;3、According to the method of micro-electronic current coupling effect, apparatus is developed for water content detecting in soil and a patent obtained. It is a innovation of detecting soil water content without weighing soil quality repeatedly in the experimental process, such as the pressure plate apparatus, vapor equilibrium method and so on.