基于GIS的马家沟滑坡稳定性计算与分区

摘要

This paper is based on the extraction and analysis of Majiagou landslide's surface,boundary and drilling information in the Three Gorges Reservoir Area.It uses GIS spatial interpolation and grid computing,combining with the mechanical formula.It then calculates and zones the stability of Majiagou No.1 landslide.First,it gets the preliminary form of the slip surface shape,which is based on proceed spatial interpolation with the known two slip plane drilling information.Then it speculates the sliding surface information of the rest four drilling with the comparison of the slip surface and the remaining four drilling stratum information.Finally,it gets the whole slip form,based on proceed spatial interpolation with all drilling information.After comparison,it analyzes the spatial interpolation methods of determining slip plane space form.It puts forward that based on a small amount accurate information of slip surface,the result can be more in line with the actual situation when using the radial basis function interpolation.It assumes that the groundwater level in the landslide body and the reservoir water level are the same.It uses the formula of infinite slope safety factor in the ArcGIS raster calculator to obtain the safety coefficient zoning map of Majiagou No.1 landslide without considering the interaction between grid columns.The calculation result shows that the unstable area of Majiagou No.1 landslide mainly concentrates in the leading edge of the sliding body,while the relatively stable areas are distributed in the front,middle and rear middle parts.And as the water level rises,the slope safety factor has a certain degree of decline.Especially the landslide leading edge can be a part of the reservoir water immersion.So the key protection governance position can be divided for Majiagou landslide,which can provide valuable reference for the prevention and treatment scheme of Majiagou landslide.%在对长江三峡库区马家沟滑坡表面、边界及钻孔信息提取分析的基础上，采用GIS空间插值及栅格计算，结合力学公式，对马家沟I号滑坡进行三维稳定性的计算和安全系数的分区。首先根据已知的两个钻孔滑移面信息进行空间插值，得到滑移面的初步形态；再利用得到的滑移面与其余4个钻孔的地层信息比较，推测出其余4个钻孔的滑移面信息；最后根据所有的钻孔信息插值得到整个滑移面的形态。在对比分析了确定滑移面空间形态的各种空间插值方法后，提出了基于少量滑移面准确信息条件下，采用径向基函数插值获得滑移面较为符合实际情况。不考虑栅格柱体之间的相互作用力，并假定滑坡体内地下水位与库水位一致，利用无限边坡安全系数计算公式，在ArcGIS栅格计算器中计算得到了马家沟I号滑坡的安全系数分区图。通过计算结果可以看出马家沟I号滑坡的不稳定区主要集中在滑体前缘，而较稳定区在前缘、中间以及后缘中间部位都有所分布；并且随着库水位上升，边坡安全系数有一定程度的下降，特别是滑坡前缘可以被库水浸没的部分。进而可以划分出马家沟滑坡的重点防护治理部位，为马家沟滑坡的防治方案提供有价值的参考。