Exploratory Research On The Detection Technology Of An Ultrasonic Energy Method For Soil Aggregate Stability

The stability of soil aggregate is a significant index to evaluate the soil structure and soil physical properties.The traditional measurement methods including Yoder wet sieving method,water drop method and so on,these methods to evaluate the stability of soil aggregate by the way of qualitative evaluation.The ultrasonic excitation method has the possibility to evaluate soil aggregate stability in the level of quantitative through studying the quantitative research of aggregates dispersion.What's more,the dynamic model of soil dispersion can be established and the dynamic dispersion process can be observed with the ultrasonic excitation method.The test object of ultrasonic excitation method usually is the soil of strong stability.While for the Loess Hilly Region,the weak stability of soil aggregate stability evaluation has more practical significance.So this study used four different types soil in Loess Hilly Region as a test object,in order to explore the applicability of three ultrasonic dispersion system,and proposed a kind of ultrasonic measurement technology can be used for the measurement of Loess Hilly soil aggregate stability.The main research and main conclusions obtained in this article are as follows:?1?Set up a simple experimental platform using the existing ultrasonic disrupted instrument.Soil aggregate dynamic fragmentation characteristics of different soil samples in Loess Hilly Region was obtained through analyzing the change of particle size distribution?PSD?and mean weight diameter?MWD?value under ultrasonic excitation.The detectability of aggregate dynamic fragmentation characteristics under tank ultrasonic dispersion system was proved.The research results showed that soil samples of three plots with different dynamic crushing characteristics JB soil sample can be fully dispersed after 300s ultrasonic excitation and GZ soil sample need more time to be fully dispersed.However,it is difficult to guarantee the calculation requirement of soil aggregate dispersion energy.There are some limitations of the current system to ensure the loss of the system is consistent.?2?It was proved that the dynamic crushing process of soil aggregates can be detected under the micro-cone probe ultrasonic dispersion system through experiment.Aggregate stability measurement experiment of four soil samples on the Loess Hilly Region was carried out.Soil aggregate decomposition characteristic curve?ADCC?was obtained based on the ultrasonic energy consumed by soil water solution.The results showed that JB,AS and GZ soil samples can be fully dispersed after 360s ultrasonic excitation by the micro-cone probe ultrasonic instrument.And according to ADCC,the dispersion characteristics of four soil samples respectively in AS,JB,GZ,and QL were different.When the aggregate of JB soil sample was fully dispersed,the ultrasonic energy consumed by a unit mass of JB soil aggregate was about 150J.The aggregate of JB soil sample is the most unstable.?3?The cylindrical probe ultrasonic dispersion system in the laboratory was improved.Aggregate stability of four soil samples?AS,JB,GZ,QL?were measured by the cylindrical probe ultrasonic dispersion system,and the energy applied to the soil water solution was quantified.And the RSA index was proposed to the characteristic relative stability of soil,the smaller the RSA,the stronger the relative stability of soil aggregates.The results showed that the four kinds of soil samples with diverse soil dispersion characteristics.What's more,RSA and the energy applied to different soil water solutions to disperse 50²000?m aggregate were different.The energy applied to soil water solution of JB soil sample was the most while the RSA was smallest.The energy applied to soil water solution of GZ soil sample was the least,while RSA value of GZ soil sample is the largest.?4?Three ultrasonic dispersion systems was comprehensively analyzed and compared to clarify the efficiency of cylindrical probe ultrasonic dispersion system was the highest,and it was most suitable for the measuremen of aggregate stability in Loess Hilly Region.RSA values were compared with MWD,geometric mean diameter?GMD?and soil erodibility K_Torri.D value and correlated with soil physicochemical properties.And the factor analysis method was used to comprehensive analysis aggregate stability of four soil samples It was similar to quantify soil aggregate stability by different soil aggregate stability index.The value of MWD and GMD were QL>GZ>AS>JB,the valve of RSA was GZ>QL>AS>JB,and the K_Torri.D value was GZ>QL>JB>AS.In contrast with the value of K_Torri.D,MWD,GMD and RSA were positive related to the content of cement material such as total nitrogen and total phosphorus,clay and so on,and negative related to sand content.The comprehensive evaluation result for aggregate stability of four soil samples was GZ>QL>AS>JB.In GZ soil sample,the content of clay and total phosphorus were high,the ability of anti ultrasonic dispersion is the greatest.While in JB soil sample,the content of organic content is less,the content of sand is high,and the anti ultrasonic dispersing ability is the smallest.