Study On The Detection Technology Of An Energy Method For Soil Aggregate Using Mechanic Stirring

As the basic component of soil structure, the stability of soil aggregate has a great relationship on soil erosion and runoff, and it is also one of the important evaluation indexes of soil quality and corrosion resistance. There are many methods for evaluating the stability of soil aggregate, but they all have some limitations. Because of its simple and convenient,stirring method is supported by soil scientists and has been widely used in the dispersion of soil and determination of soil physical and chemical properties. If stirred energy can be calculated during stirring, it can effectively and quantitatively assess the stability of soil aggregate. However, there are no suitable means and methods to detect the energy.In terms of the shortcomings of the above mentioned detection technology of soil aggregate stirred energy, the main conclusions of this paper are as follows.:(1) An experimental platform for measuring stirred energy was set up. According to the design of soil aggregate stability quantitative assessment system using ultrasonic dispersion,the measurement system consisted of a stirrer, a data logger and a computer. The experimental platform was respectively set up with a high speed stirrer and a low speed stirrer to carry out the test by Yangling Lou Soil. When stirring soil with the high speed stirrer, the dispersion was too fast, which was not conducive to the observation of the dynamic process of soil dispersion. And the speed of the low speed stirrer is moderate. The content of soil mass less than 0.05 mm reached 0.90 while stirring 420 s, which was the same as that of the high speed stirrer of 30 s. The dispersion rate was significantly lower than that of the high speed stirrer. It showed that the test of low speed stirrer could be a good way to observe the dispersion process of the soil. Therefore, this study selects the low speed stirrer, which lays the foundation for follow-up soil aggregate stirred energy test.(2) An energy method to evaluate the stability of soil aggregate was proposed.According to the law of conservation of energy through the power of soil solution and completely broken soil power subtraction integral, a stirred energy method was proposed. And Experiments with pure water and dispersed soil and aggregate soil were conducted and validated the innovated method. Moreover, Red soil from Jiangxi Province, Black soil from Jilin Province, and Lou soil from Yangling, Shaanxi Province were tested and their stirredenergies during dispersion were found to be 48.59 J g-1, 28.67 J g-1, 25.59 J g-1, respectively.And then compared it with the traditional wet sieve method. The results are as follows: The two methods are consistent with the results of stability analysis. The Red soil from Jiangxi Province has largest stables. Thus the feasibility of the method is proved to judge the stability of soil aggregate.(3) The changes of stirred energy under different parameters were studied. Experiments of different speed and concentration of Black soil were carried out to study the change of soil dispersion and stirred energy. The results were as follows: The higher the speed, the greater the soil dispersion degree, and the greater the stirred energy. And the higher the concentration,the faster the soil dispersion degree, and the higher the stirred energy, but the change was not obvious. The relationship between soil dispersion and stirred energy was the same as the Soil Dispersion Characteristic Curve proposed by North. They both showed that the dispersion degree of soil increased fast at first, and then slowed down with the increase of energy. And finally reached a maximum value. At this time the soil reached a completely dispersed state.Therefore, it is concluded that the speed of Black soil is the most suitable for 3000 rpm, and the concentration has little effect.(4) The dynamic process of soil stirring was studied, including the relationship between particle size distribution and stirring time as well as the relationship between particle size distribution and stirred energy. The research objects were three kinds of soil samples and different speed and concentrations of Black soil. The results were as follows: The relationship between soil particle size distribution and stirring time was found to be nonlinear. Before the total dispersion, the content of the large aggregate had been reduced, while the content of the powder had been increased. The relationship between soil particle size distribution and stirring time was different with the different speed of different soil samples. The relationship of soil particle size distribution with stirred energy was found to be nonlinear, and it was the same as that of SDCC curve. Before the total dispersion, the relationship between the percent content of the soil mass and the stirred energy was not equal to the distance. The relationship between soil particle size distribution and stirred energy was different with the different speed of different soil samples. Thus the practicability of the system is verified again.