【摘要】 当前棉秆起拔过程中，棉秆根系-土壤界面作用机制复杂，缺乏高精度仿真模型，进而导致起拔机械在结构设计与参数优化方面面临困难。为此，基于离散元法(DEM),构建了新疆棉田典型土壤的粘结模型及棉秆根系-土壤系统，系统揭示起拔过程中的界面力学响应与破坏机制。通过无侧限抗压试验与Box-Behnken设计(BBD)相结合，完成土壤粘结参数的标定，得到最优组合：单位面积法向粘接刚度1.05×10~8 N/m~3、单位面积切向粘接刚度3.09×10~8 N/m~3、单位面积法向粘结应力6.95×10~5 Pa/m~2、单位面积切向粘结应力6.69×10~5 Pa/m~2,仿真与试验结果的轴向压力误差为1.7%。在此基础上，基于EDEM软件构建了棉秆根系-土壤系统模型，并通过仿真与田间试验对比验证，预测起拔力为592.56 N,与实测值598.2 N的相对误差为1%。进一步分析起拔力-时间曲线，界面响应过程可分为弹性加载、峰值加载、衰减和残余稳定4个阶段，分别对应剪应力积累、粘结破坏、根-土滑移及残余接触；揭示了剪切力主导起拔阻力演化，破坏模式受根径与土壤条件共同影响的机制。本研究为棉秆类作物根-土界面的高精度建模提供了仿真方法支撑，同时为起拔结构设计与作业参数优化提供理论基础。更多还原

【Abstract】 In the current cotton stalk pulling process, the interaction mechanisms at the root-soil interface are highly complex, and there is a lack of high-fidelity simulation models, which significantly hinders the structural design and parameter optimization of pulling machinery. To address this issue, the discrete element method(DEM) was employed to construct a cohesive soil model and a root-soil composite system representative of typical cotton fields in Xinjiang, aiming to systematically reveal the interfacial mechanical responses and failure mechanisms during the pulling process. Soil bonding parameters were calibrated by using unconfined compression tests combined with a Box-Behnken design(BBD) optimization approach, yielding optimal values: normal bonding stiffness of 1.05×10~8 N/m~3, tangential bonding stiffness of 3.09×10~8 N/m~3, normal bonding strength of 6.95×10~5 Pa/m~2, and tangential bonding strength of 6.69×10~5 Pa/m~2. The axial pressure simulation error was 1.7%, confirming model accuracy. Using these parameters, a root-soil model was constructed in EDEM software and validated against field tests, with the predicted uprooting force(592.56 N) closely matching the measured value(598.2 N), showing a 1% error. Uprooting force-time curve analysis revealed four distinct response stages: elastic loading, peak loading, attenuation failure, and residual stabilization, reflecting shear stress buildup, bond rupture, root-soil slippage, and post-failure contact. The results showed that shear stress dominated resistance evolution, and the failure mode was jointly affected by root diameter and soil conditions. The research can provide an effective simulation framework for modeling root-soil systems for the design optimization of uprooting mechanisms.更多还原