滨海盐碱地耕作层土壤离散元仿真参数标定方法

Calibration of Discrete Element Simulation Parameters for Cultivated Soil Layer in Coastal Saline Alkali Soil

摘要:

为获取滨海盐碱地土壤离散元仿真参数，以黄三角农高区土壤为例，采用试验与离散元仿真相结合的方法，选取EDEM中Hertz-Mindlin with JKR作为仿真接触模型，对土壤离散元参数进行标定。通过Plackett-Burman试验进行显著性分析，探寻对土壤堆积角有显著影响的因素，采用最陡爬坡法进一步确定因素取值范围，应用Box-Behnken试验建立3个显著性因素与土壤仿真堆积角的二次多项式回归模型，以实测土壤堆积角33.6°为目标对回归模型进行寻优，得到最优组合：土壤-土壤静摩擦因数为0.546、土壤-土壤恢复系数为0.358、JKR模型土壤表面能为3.207J/m2。在最优参数组合条件下，孔顶外径和穴孔纵深仿真结果与试验结果误差分别为4.04%和3.47%，验证了土壤参数标定的准确性。本文提出的盐碱地土壤离散元参数标定方法及参数值，可为盐碱地作业条件下触土部件与土壤互作的离散元仿真及盐碱地专用农机具研发设计提供理论基础与支撑。

Abstract:

In order to obtain the discrete element simulation parameters of coastal saline soils, the soil discrete element parameters were calibrated by combining the experiment and discrete element simulation using the soil of the Yellow River Deltd Agricultural Highland Area as an example, and Hertz-Mindlin with JKR in EDEM was selected as the simulation contact model. The significance analysis was carried out through the Plackett-Burman test to explore the factors that had a significant effect on the soil stacking angle, the steepest climb method was used to further determine the range of factor values, the Box-Behnken test was applied to establish a quadratic polynomial regression model of the three significance factors and the simulated stacking angle of the soil, and the regression model was performed with the measured soil stacking angle of 33.6° as the target. The optimal combination of soil-soil static friction factor of 0.546, soil-soil recovery coefficient of 0.358, and soil surface energy of 3.207J/m2 in the JKR model was obtained. Under the conditions of the optimal parameter combination, the simulation results of the outer diameter of the top of the hole and the longitudinal depth of the hole had an error of 4.04% and 3.47% from the test, respectively, which verified the accuracy of the soil parameter calibration. The discrete element parameter calibration method and parameter values proposed for saline alkali soil can provide theoretical basis and support for the discrete element simulation of the interaction between soil contact components and soil under saline alkali working conditions, as well as the research and design of specialized agricultural machinery for saline alkali soil.