Soil Disturbance Behavior Of Subsoiling Based On Discrete Element Method

Mechanization subsoiling can effectively improve the structure of farmland soil and provide the basis for the sustainable development of agricultural production.Aiming at the problem of disturbance mechanism of subsoiling,the mechanism of the interaction between subsoiler and soil was studied by using high speed photography,soil bin test and discrete element method.The influence of key structure parameters of subsoiler on soil disturbance was proved,which provided a basis for understanding the disturbance mechanism of subsoiling,optimizing the structure parameters of subsoiler and improving the quality of subsoiling.1.Soil parameter determination and boundary model building.In order to establish an accurate discrete element simulation model,the physical parameters such as texture and moisture content of soil(Lou soil)were measured,and the boundary model of subsoiler and soil particles with different structural parameters was constructed.2.Study on disturbance mechanism of subsoiling based on discrete element method.Based on the analysis of interaction process between subsoiler and soil,the disturbance mechanism of subsoiling was analyzed by means of high speed photography and discrete element method,which combined with soil bin test.The results showed that: 1)The disturbance range of soil decreases with the increase of distance between soil and subsoiler,and the range in different position from large to small is shallow,middle and deep layer.2)The movement velocity of soil decreases with the increase of distance between subsoiler and soil,and in different depth,the movement velocity of soil particles is different in x,y and z direction.3)The shape of soil disturbance section of simulation and experiment were basically consistent,and the error of soil bulking,soil disturbance coefficient and vertical stacking angle of soil surface between simulation and experimental values were 13.21%,17.38% and 9.42%,respectively.3.Analysis of soil movement behavior between subsoilers based on discrete element method.On the basis of analyzing the influence of double shovels synergistic effect on soil disturbance process,the soil disturbance behavior of subsoilers was studied by using soil bin test and discrete element method.The results showed that: 1)The horizontal and vertical disturbance range of soil decreases with the increase of the distance between soil and subsoiler;2)The force and velocity of soil particles in different positions decreased with the increase of the distance between the soil particles and subsoiler.3)The shape of soil disturbance section of simulation and experiment were basically consistent,and the error of soil bulking and soil disturbance coefficient between simulation and experimental values were 14.45% and 12.06%,respectively.4.Effects of key structural parameters of subsoiler on soil disturbance behavior.The influence of rake angle,the shape of subsoiler tine,spacing of subsoiler on soil disturbance was studied.The results showed that:1)When the the shape of subsoiler tine is arrow,chisel and wing,the average force and disturbance width of soil particles from large to small are wing,arrow and chisel,the average movement speed from large to small is arrow,chisel,wing;2)The average force difference of soil particles is smaller when the rake angle is 18,23 and 28,respectively,the average velocity and the disturbance width increase with the increase of the rake angle;3)When the spacing of subsoiler is 300,400 and 500 mm,respectively,the average force of soil particles showing a trend of increases first and then decreases with the increase of the spacing of subsoiler,the average movement velocity varies greatly with the spacing of subsoiler,and the disturbance width increases with the increase of the spacing of subsoiler,the accumulation height of soil in the surface decreases with the increase of spacing of subsoiler.