黄土水力侵蚀与滑坡互馈机制及其风险预警

The Loess Plateau is the key area of the Western Development, and the core area of the One Belt, One Road in China. At the same time, it is also the most intensive area with soil erosion and landslide disasters. At present, with the increasingly frequent activities of human urbanization construction projects, the harmfulness of hydraulic erosion and loess landslide is also increasingly serious, which has restricted the loess area sustainable development. The global largest loess plateau - Dongzhi Plateau is under threat of erosion and disintegration. Therefore, it is urgent and necessary to mitigate and prevent hydraulic erosion and loess landslides. This project utilizes the interdisciplinary research method, disasters-formative environment and modes of hydraulic erosion type landslide disasters in loess area will be studied, including common characters and dynamic interaction mechanism in the Loess Landslide under the different hydraulic erosions; through the large-scale physical simulation experiment and numerical simulation, the disaster forming process of loess landslides induced by hydraulic erosion is reconstructed, the instability mechanism of hydraulic erosion type loess landslides and the evolution process and law of the disaster chain will be analyzed; the methods of early warning and control technology of hydraulic erosion type loess landslide -mudflow disasters chain will be researched and proposed, and this will be helpful for providing basic scientific basis for urban construction and disaster reduction and prevention in the loess region of China. This results will provide new ideas for the living environment and engineering construction to effective prevention and control of landslide disasters in the Loess Plateau area, and provide scientific and technological support for the construction of ecological civilization and disaster prevention and reduction in the Loess Plateau.

黄土高原是我国一带一路的核心区、西部大开发的关键区，同时又是水土流失、滑坡灾害最密集的地区。目前，随着人类城市化建设工程活动日益频繁，水力侵蚀及黄土滑坡的危害性也日趋严重，全球最大的黄土塬-董志塬面临侵蚀解体的威胁，因此急需开展黄土水力侵蚀和滑坡灾害互馈机制的研究，且十分迫切。本项目通过多学科联合手段，研究黄土地区水蚀型黄土滑坡灾害的孕灾环境与成灾模式；不同水力侵蚀作用下黄土滑坡的共性规律和互馈机制；通过大型物理模拟和数值仿真，再现黄土水力侵蚀引发黄土滑坡的成灾过程，失稳机制及其灾害链的演化过程与规律；研究并提出黄土水力侵蚀-黄土滑坡-泥流灾害链预警的理论方法及预防控制技术，为我国黄土地区城镇建设及减灾防灾提供基础科学依据。研究成果将为黄土高原地区的人居环境与工程建设有效防治滑坡灾害提供新的思路，为黄土高原地区生态文明建设和防灾减灾提供科技支撑。

黄土高原是我国一带一路的核心区、西部大开发的关键区，同时又是水土流失、滑坡灾害最密集的地区。目前，随着人类城市化建设工程活动日益频繁，水力侵蚀及黄土滑坡的危害性也日趋严重，全球最大的黄土塬-董志塬面临侵蚀解体的威胁，因此急需开展黄土水力侵蚀和滑坡灾害互馈机制的研究，且十分迫切。本项目通过多学科联合手段，研究发现：1）在水力侵蚀路径上，土壤水分含量较大，容易诱发滑坡，滑坡进一步又加剧了水力侵蚀；2）沟头填埋工程的实施对侵蚀沟周围水土环境产生较大影响，地下水位抬升，回填区域土壤质地、植被的变化等共同作用导致了这种结果；3）地表水的不合理疏导极易导致沟头回填工程的表土侵蚀，可能由细沟持续侵蚀发展成大的切沟侵蚀，影响固沟保塬工程的稳定性；4）沟头填埋工程在短期内可以降低水力侵蚀强度，减少滑坡；但从大时空尺度来看，水力侵蚀可能会加剧滑坡，反之滑坡又可能促进水力侵蚀；因黄土特性诱发的原生灾害及其引起的次生灾害组成的灾害序列往往存在时间上先后顺序，空间上彼此相依，成因上相互关联的灾害链式关系。灾害链一旦发展演化，致灾能力极强，致灾规模极大；5）目前的治理模式主要有简单填埋、排水+填埋、排水+填埋+护坡、排水+填埋+生态护坡型4种，其中排水+填埋+生态护坡型治理模式效果最为佳；6）针对董志塬火巷沟回填坡面的激光雷达扫描发现，坡面排水设计的不合理导致细沟侵蚀普遍发育，加剧了回填坡面的表土侵蚀，据此提出了波浪式横向排水沟+竖式排水沟相结合的排水方式。建议在后期工程设计中应加强回填工程中塬面和坡面排水设计的合理性，导水管道尽量用明管导水，降低管道漏水破坏回填工程的风险；7）提出了黄土水力侵蚀-黄土滑坡-泥流灾害链预警的理论方法及预防控制技术，为我国黄土地区城镇建设及减灾防灾提供基础科学依据。成果将为黄土高原地区的工程建设有效防治滑坡灾害提供新的思路，为地区生态文明建设和防灾减灾提供科技支撑。