耕作部件作用下的天然退化草地土壤-根系复合土层结构界面耦合失效机制研究

The interface coupling failure mechanism of soil-root composite structure underground under the action of tillage tools on degraded natural grassland will be studied in this project. The soil layer with soil-root composite structure existed in the shallow subsurface of natural grassland (Leymus chinensis) intensifies the hardening degradation degree of the grassland, and increases the difficulty of mechanical restoration operations. The design and optimization of suitable tillage tools and components used for degraded natural grassland improvement need the soil-root-grass-machine interaction mechanism as bases. The lack of fundamental research and unclear coupling failure mechanism between the soil-root composite structure and tillage tools, has become a technical shortcoming which restricts the development of degraded natural grassland mechanization restoration technology. This project focus on the research of interface coupling failure mechanism of soil-root composite structure underground under the action of tillage tools during its on-the-go movements, basing on the analysis of roots constitutive characteristics, a soil-root composite layer structure visualization model would be constructed. The interface coupling mechanical model of the composite soil layer and tillage tools would be built by analyzing the coupling stress between the tillage tools and composite soil layer, and the influence of the interface coupling parameters on the coupling effect would be analyzed as well. At the same time, the failure characteristics such as the failure mechanism, soil translocation, and failure status of the soil-root composite layer structure would also be studied. So that the interface coupling failure mechanism of soil-root composite layer structure underground under the action of tillage tools would be revealed. This project could provide theoretical support for constructing rational grassland cultivation layer, improving the key technology of degraded natural grassland improvement, and designing and optimizing suitable tillage tools.

本项目将对耕作部件作用下的天然退化草地土壤-根系复合土层结构界面耦合失效机制开展系统研究。天然草地（羊草）亚表层形成的土壤-根系复合土层结构（简称“复合土层结构”）加剧了草地板结性退化趋势，加大了机械化改良作业难度，而适宜改良耕作部件的研发和优化需要以土-根-草-机互作机理为理论支撑，基础研究薄弱、复合土层结构耦合失效机制不明，成为制约草地机械化改良技术发展的技术短板。对耕作部件作用下的草地复合土层结构界面耦合失效机制开展研究，在分析根系本构特征的基础上，构建复合土层结构可视化模型，通过分析耕作部件与复合土层结构界面耦合应力，建立二者的界面耦合力学模型，并分析界面耦合参数对耦合效应的影响，同时分析复合土层结构界面失效机制、运移状态和失效状态等失效特性，进而揭示耕作部件与复合土层结构界面耦合失效机制，为构建草地土壤合理耕层、完善草地改良关键技术、研发和优化设计适宜改良耕作部件提供理论支撑。

天然草地（羊草）亚表层形成的土壤-根系复合土层结构（简称“复合土层结构”）加剧了草地板结性退化趋势，加大了机械化改良作业难度，而适宜改良耕作部件的研发和优化需要以土-根-草-机互作机理为理论支撑，基础研究薄弱、复合土层结构耦合失效机制不明，成为制约草地机械化改良技术发展的技术短板。本项目立足于机械化改良退化草地中遇到的理论问题和现实问题，结合理论分析、试验论证（土槽、田间）等多种手段，围绕耕作部件作用下的草地复合土层结构界面耦合失效机制开展研究，构建了复合土层结构可视化模型；建立了耕作部件与复合土层结构界面力学模型；分析了界面耦合参数对耦合效应的影响，以及复合土层结构界面失效机制、运移状态和失效状态等失效特性，揭示了耕作部件与复合土层结构界面耦合失效机制与失效机理；在此基础上，以牵引力、地表翻垡率和地下扰动系数为指标系数，构建了耕作部件作业适用性评价模型。项目研究内容为研究草地土壤合理耕层构建机理与优化方法、研发和优化设计适宜草地改良耕作部件以及完善草地机械化改良技术提供了有效理论支撑和数据支持。