基于DEM的三维微条柱法计算滑移型塌岸安全系数的研究

Study on Calculation Method of the Factor of Safety of Bank Failure of Sliding Mode Based on DEM-supported Micro-column Method

为了对边坡进行三维稳定性分析,在传统的二维条分法的基础上进行拓展,基于高分辨率DEM构建边坡三维模型,将二维条分法中的土条拓展为三维条柱法中的条柱,通过分析每个条柱上的受力状况,根据极限平衡理论,以GIS二次开发的方式,将三维毕肖普法引入GIS软件平台,实现了三维圆弧滑动面的构造和三维安全系数的计算,该方法实现了三维模型构建与三维安全系数计算过程的自动化和一体化。应用本方法,以金沙江溪洛渡库区老木沟滑移型塌岸体为例,进行三维稳定系数的计算,与二维计算结果相比,结果偏于安全,主要的原因在于将滑动面视为球形滑动面,因此需要在程序中加入控制性结构面或控制性节点,使其与实际情况更加接近。

When the slope stability is calculated,it is usually simplified to two-dimensional plane strain problem.The limit equilibrium method is used to calculate the safety factor after two-dimensional slicing of the main section.Obviously,it is a simplified model of the reality of a slope,although the phenomenon of slope failure occurred in the three-dimensional space.Strictly,a three-dimensional slope stability analysis should be performed.The paper provides a three-dimensional micro-column method which has expanded the traditional two-dimensional slice method and built the three-dimensional slope model based on high-resolution DEM.In this method,the soil slices in two-dimensional slice method have accordingly transformed the soil columns.Lastly,through analyzing the force condition of every column,based on the limit equilibrium theory,three-dimensional Bishop method is imbedded into GIS software platform by secondary development mode,and the three-dimensional spherical sliding surface is constructed and the three-dimensional factor of safety is calculated.The method realizes the automation and integration of 3-D model construction and 3-D safety factor calculation process,and expands the application of high-resolution DEM in geotechnical engineering field.