基于高光谱的河岸植草混凝土细观结构与草本根系生长机制研究

The revetment technology using vegetation porous concrete is an important development demand of ecological water conservancy, but currently the basic theory research of vegetation porous concrete is lack, they are unclear that the relationship between its macro physical and mechanical properties and mesostructure with multiphase heterogeneous material, and herbaceous roots growth characteristics in the environment of random porous materials, it hindered technology innovation and application development of vegetation porous concrete. So, this project is based on the vegetation porous concrete in river’s ecological revetment as the research object, with the aid of hyperspectral technology, vegetation porous concrete is monitored step by step by hyperspectral images from the perspective of mesoscopic structure, the distribution and morphological characteristics of different materials are extracted and analyzed, such as aggregate, gelled material, suitable vegetation soils, herbaceous roots and pore spatial; The three-dimensional finite element mathematical model of the vegetation porous concrete was constructed, and the pore structure factors are obtained, and the mechanical model calibration are implemented to simulate analysis. The relationship between the mesostructure and the macroscopic physical and mechanical properties was also discussed. At the same time, according to the characteristics of the root growth distribution, the fractal dimension theory was used to reveal the growth mechanism and its effect of herbaceous roots in porous concrete environment, and the effects of herbaceous roots on the microstructural characteristics and physical and mechanical properties were explored. These studies will solve the problem of the relationship between the mesostructure l structure and the growth distribution of herbaceous roots. The results will provide important theoretical support and new ideas for promoting the revetment technology innovation and development of ecological river, and for achieving the harmonious and sustainable development of human and water.

植草混凝土护岸是生态水利的重要发展需求，但当前对植草混凝土的基础理论研究缺乏，其宏观物理力学表征和多相非均质材料细观结构的关系、随机孔隙环境下草本根系生长变化特征尚不清楚，阻碍了植草混凝土的技术创新和应用。为此，本项目以河流护岸的植草混凝土为研究对象，从细观结构的角度，借助高光谱图像技术，对植草混凝土逐层进行图像解译，提取和分析其骨料、胶凝材料、适生材料、孔隙和草本根系等的分布与形态特征；构建植草混凝土的三维有限元数学模型，获取孔结构要素，对模型进行参数率定、验证和模拟分析，阐明其细观结构与宏观表征之间的关系；同时应用高光谱技术和分形理论揭示植草混凝土环境下草本根系的生长机制及对其影响，探究草本根系对混凝土细观结构特征和物理力学性能的影响，解决植草混凝土细观结构与草本根系生长特征的关联问题。项目成果将为推动生态河流护岸技术领域的创新发展提供重要理论支撑和新思路，实现人水和谐的可持续发展。

植草混凝土护岸是河流生态治理新要求下的重要产物，但植草混凝土的基础理论研究极少，其宏观物理力学表征和多相非均质材料细观结构的关系、随机孔隙环境下草本根系生长变化特征尚不清楚。项目以试验研究、理论分析、数值模拟为手段，分析了混凝土组分、孔隙和草本根系等分布与形态特征，阐明细观结构与宏观表征之间的关系，揭示了植草混凝土环境下草本根系的生长机制及影响。取得了一些有价值的成果：（1）揭示了植草混凝土组分和孔隙的形态特征。目标孔隙率与孔隙等效半径、有效通孔率、形状因子、分形维数成正比，与孔隙迂曲度呈负相关性，目标孔隙率越大且水灰比越小时，混凝土孔隙细观结构越有利于草本植物根系生长。（2）通过三维有限元模拟分析，揭示了植草混凝土力学作用机理；利用化学试剂改良方法，自主研发了植草混凝土外加剂。（3）项目提出了植草混凝土孔内碱性环境改善方法及工艺；发明了基于草本根系构型的植草混凝土构造方法；发展了装配式植草混凝土概念，该结构能够有效地减少流速、提高混凝土保土和抗冲刷性能。（4）通过植生试验和理化分析，揭示了植草混凝土环境胁迫下草本根系的生长机制。草本植物的生长速率、根系生长特征受到混凝土介质影响；草本植株生长高度随混凝土厚度的增加而降低，根系最大长度、总根长、根表面积、根平均直径、总根体积及根尖数等根系特征参数随目标孔隙率的增大而增加明显；植草混凝土胁迫下使得根系结构更加复杂、分支模式更接近叉状分支模式；根系分形特征、拓扑指数与根长、根表面积等主要根系形态参数极显著相关。成果在黎川县樟溪水、九江长江岸线、进贤县柴埠口等河湖治理工程中示范应用，成效显著。成果有利于丰富植草混凝土的基础理论和技术，为推动植草混凝土在生态河流护岸技术领域的创新发展提供重要理论支撑和新思路。