基于典型剖面分析的区域斜坡稳定性分区方法

METHOD OF ZONING OF REGIONAL SLOPE STABILITY BASED ON TYPICAL PROFILES ANALYSIS

为了研究大范围内区域斜坡的稳定性,本文提出了一套基于典型剖面分析的区域斜坡稳定性分区方法。首先,在ArcGIS水文分析的基础上划分斜坡单元;其次,利用MATLAB开发程序,完成斜坡单元的剖分、典型剖面的搜索和提取工作;再次,利用MATLAB动态生成FLAC^(2D)命令流文件,自动计算得到区域斜坡稳定性系数的分布;最后,基于定量计算在ArcGIS中对区域斜坡进行稳定性分区评价。本文选取陕西耀县幅1︰5万环境地质调查区内黄土斜坡较发育段作为研究对象,对本方法进行验证。计算结果:(1)研究区域划分为不稳定区、基本稳定区和稳定区3个区;(2)整个方法体系采取智能化的设计理念,各计算步骤之间自动调用执行,程序衔接良好;(3)将GIS分析与外部计算相结合,实现单个斜坡的稳定性计算到区域的推广。

The zoning of regional slope stability has very important significance for the landslide disaster prevention. In order to study regional slope stability, this study provides a regional slop stability zoning method in loess areas based on typical profiles. At first, the whole study area is divided into slope units using hydrology tool in ArcGIS.The raster data of the slope unit distribution and the DEM are imported into M A T L A B . Secondly, the slope profiles in each unit are extracted along the average aspect calculated using least squares method. O n e profile represents one slope unit. Thirdly, MATLAB is used to formulate the c o m m a n d line files of F L A C 20 ,including all the information of each profile, material parameters of soil, initial saturation, pore pressure conditions, constraint boundary and so on. Then all the c o mmand line files of F L A C 20 are executed automatically. T he strength reduction method is induced to calculate the stability of each typical profile. Finally, the distribution of safety factor is mapped on the study area. In order to evaluate regional stability intuitively, w e m a k e the regional slope stability partitions for further assessment. We select Yaoxian as the study area and divide 946 typical profiles to calculate the stability of every slop unit. T he study area is divided to three zones： unstable region, fundamental stable region and stable region. The zoning result is consistent with the actual survey. W e can apply a single slope quantitativecalculation to the whole region and combine the GIS analysis with external program calculation. This method improves the computation efficiency and accuracy effectively and can find potential sliding surface of the landslide. It is a new thought for prediction of regional slop stability in loess area.