淤地坝减轻坡沟系统滑坡侵蚀的数值模拟

Numerical Simulation for Reducing Slide Erosion in Slope-gully System by Check Dam

基于边坡分析软件及有限元软件,通过建立陕北绥德县关地沟4号坝上游典型坡沟系统的概化模型,应用概率统计和数值仿真分析方法,从坡沟系统的力学稳定和受力破环的角度,得到了随淤地坝坝地的逐渐淤高坡沟系统的稳定性、滑塌概率和滑塌量分别增强、减弱和减少,其随坝地淤高的变化分别满足二项式、二项式和直线规律。应用有限元强度折减法原理,对坡沟系统的应力场和位移场进行了仿真分析,指出了稳定系数最小,滑坡概率最大时坡沟系统濒临滑坡侵蚀时的最大应力和位移分布区域:(1)X方向的最大位移是沟坡中下部位垂直向坡体内约15m的范围;(2)Y方向的最大位移是从峁顶向两侧各延伸10m左右的扇形区域;(3)拉应力最大值区域是从峁顶经峁坡向沟坡坡缘线向坡体内延伸9m左右的带形区域。研究结果可为坡沟系统水土保持工程措施的配置及生物措施的实施提供有益的参考,并为评价坡沟系统的稳定性提供一定可靠度的依据。

Based on slope analysis software and finite element software, simulation analysis method and prob- ability statistics were applied by establishing a generalization model of Guandigou watershed in Suide County of Northern Shaanxi Province that is a classical slope-gully system. Concerning on the mechanical stabiliza- tion and damage by stress in the slope-gully system, the stability, land sliding probability and land sliding a- mount of the slope-gully system with gradual dam land rise were enhanced, weakened and reduced, respec- tively. Variation of the dam land rise satisfies binomial, binomial or linear relation. The stress field and dis- placement field in the slope-gully system were also analyzed by FEM（finite element method） strength reduc- tion theory. When the stability factor was the lowest, the land sliding probability was the greatest, and the slope-gully system was on the edge of sliding erosion, the maximum stress and displacement fields obtained were as follows： （1） The maximum displacement of X direction： the region about 15 m perpendicular to vivo slope in the middle and lower segment of slope-gully system; （2） The maximum displacement of Y direction： the sector region of about 10 m extension from the top of mound slope to both sides; （3） The maximum re- gion of tensile stress, strip region of about 9 m vertical extension from the top of mound slope to the edge line of gully slope, through mound slope. The result may offer valuable reference for allocating the engineer- ing measures of soil and water conservation and implementing the biological measures, and provide a certain reliability basis for evaluating the stability of slope-gully system.