黄土高原小流域重力侵蚀数值模拟

Numerical simulation on gravitational erosion of small watershed system in Loess Plateau

为研究黄土高原小流域重力侵蚀机理,采用fish语言编写多层复杂地形建模的前处理程序,对多层复杂地形建模进行了二次开发。从力学稳定性角度,采用有限差分FLAC3D软件对黄土高原小流域概化模型进行重力侵蚀机理研究,分析了流域重力侵蚀的发育过程,并对小流域位移场和应力场进行了数值模拟。结果表明:建立的三维模型能真实地表现小流域地形、地貌,仿真效果良好。小流域重力侵蚀过程分为发育期、成熟期和稳定期3个阶段,沟头溯源区是小流域侵蚀最强烈的部位;凹形的边坡整体几何形态利于边坡稳定,减缓了重力侵蚀的发生程度。建模方法和数值模拟结果可应用到重力侵蚀研究中,为推动流域侵蚀产沙时空规律研究的深入发展和小流域水土流失综合治理以及生态环境建设提供科学依据。

To study the mechanism of gravitational erosion,pre-treatment program for modeling of complex multilayered terrain using fish language was compiled and the modeling was developed secondly.The finite difference software Flac 3D was used to study the mechanism of gravitational erosion,to analyze the development process of gravitational erosion,and to numerical simulate on displacement field and stress field of small watershed in Loess Plateau concerning on the mechanical stabilization.The results showed that the three-dimensional model established could factually demonstrate topography and geomorphology of the small watershed and had good simulation effectiveness.The process of gravitational erosion was divided into three stages,the development stage,maturity stage and stable stage.Gravitational erosion of the traceability area was the most serious;the geometric shape of concave slope conductived to the stability that slowing down the occurrence degree of gravitational erosion.The modeling method and numerical simulation results could be applied to study gravitational erosion that offer scientific basis for the deeply promoting the development of erosion and sediment yield time-space law and comprehensive controlling soil erosion of small watershed and constructing the ecological environment.