黑土坡耕地冻融—水力复合侵蚀动力过程与量化表征

复合侵蚀机理是坡面土壤侵蚀过程机理研究的重要基础理论。目前冻融-水力（融雪、降雨）复合侵蚀机理研究仍十分薄弱，直接影响到复合侵蚀作用下侵蚀预报模型的可靠性和可信度。本项目以冻融-水力复合侵蚀作用强烈的东北典型黑土坡耕地为研究对象，采用野外定位观测、控制条件试验、实体模型模拟和数值模拟相结合的研究方法，引入界面应力测定技术（IMM）和粒子图像测速技术（PIV）等交叉学科研究手段，针对研究区特殊的冻融-融雪-降水复合侵蚀特点，以多侵蚀营力互作下土壤可蚀性和力学特性的响应为基础，通过对温度场-渗流场-应力场的耦合分析，揭示多侵蚀营力互作下水（冰）-土界面的侵蚀动力机制，构建和验证冻融-水力复合侵蚀动力过程模型，进而识别与量化冻融、融雪和降雨径流侵蚀营力在复合侵蚀动力过程中的贡献。研究结果可为复合土壤侵蚀研究提供新的思路，并为复杂侵蚀环境下的坡面土壤侵蚀预报及黑土坡耕地复合侵蚀防治提供科学理论。

Mechanism of hybrid soil erosion is critical to soil erosion processes. Due to the rare investigation of hybrid soil erosion induced by freeze-thaw and water alternation (i.e., snow melt, rain fall), the reliability and credibility of current soil erosion predictions are questionable. To meet needs of implementing soil conservation practices in China, especially for one of the serious eroded area -- the black soil region in NE China, a systematic study on the dynamic mechanism of hybrid soil erosion process is need to be conducted. The experimental investigations on dynamic mechanism of hybrid erosion and its indicators will be studied by field investigating, in-situ monitoring, simulation experiments, combining with laboratory physical-chemical analysis and statistical analysis. Moreover, particle image velocimetry (PIV) and interfacial stress measurement (IMM) techniques are introduced in this study. In accordance with the special characteristics of hybrid erosion, variation and uncertainty of driving force for different erosional agents will be studied, such as soil erodibility and mechanical property. On the basis of coupling analyses of thermal-hydro-mechanical behavior, which is highly non-linear and complex, a hybrid soil erosion dynamic model induced by freeze-thaw and water should be established. Interaction erosional mechanism among snow melt, seepage, rainfall and freeze-thaw agents will be exposited. Contribution of each agent of hybrid erosion process would be estimated by the newly established model. The expected results will provide a new approach for hybrid erosion research, and provide theoretical support to black soil resource protection and conservation practices.