吕梁机场黄土滑坡特征及其三维稳定性分析

Geological features of loess landslide at Lüliang airport and its 3D stability analysis

吕梁机场滑坡是机场建设前期发现的一处大型黄土滑坡,由于滑坡的东北侧为机场主跑道,因此,该滑坡对机场建设以及建成后的运营存在较大的影响。在详细的工程地质勘察和测试分析工作基础上,首先,分析了滑坡的特征和形成机制,进而评价了滑坡的稳定性;其次,通过勘察认为该滑坡为黄土层内发育的多层滑坡,在地貌上呈3级台阶,主滑坡滑动面位于离石黄土的古土壤层内;最后,利用GIS建立了滑坡的三维地质模型,并采用极限平衡法和强度折减法分析,分别评价了吕梁机场滑坡不同滑体的稳定性。三维极限平衡结果表明:该滑坡大多数分级、分块滑体在天然状态下处于稳定、基本稳定状态,强度折减分析得到的整个滑坡的安全系数为1.26,最危险区域出现在II级滑坡后缘以及I-3滑坡,在上部加载或降雨情况下有可能再次发生滑动。总之,三维稳定性分析可以更真实地反映滑坡的真实状态,尤其是对于条件复杂的滑坡。

The Lüliang airport landslide is a large loess landslide which was found in early construction of the airport.Due to airfield runway next to the northeastern of the landslide,the landslide makes a large influence on the engineering construction and safe operation.In order to assess landslide risk and prevent its damage,the geological features and formation mechanism of the landslide are analyzed based on the detailed engineering geological investigation and testing work.The landslide is considered as a multilayer landslide developed in loess layer.There are three steps on the landslide;and the main sliding surface locates in the paleosol layer of Lishi loess.Three-dimensional geological model is established using GIS;and the stability of the landslide is evaluated by limit equilibrium method and shear strength reduction method.Results from three-dimensional limit equilibrium analyses show that most parts of the landslide are stable or basic stable in natural state.From strength reduction analysis,the safety factor of the whole slope is 1.26.It is shown that the most dangerous areas appear in the posterior margin of landslide II and landslide I-3.In case of loading or rainfall condition,it is likely to slide again.In conclusion,three-dimensional stability analysis can more truly reflect the actual state of landslides,especially for complex landslide.