中兰铁路黄土滑坡发育特征及成因机理研究

Study on the Development Characteristics and Genetic Mechanism of Loess Landslides on the Zhongwei-Lanzhou Railway

中兰铁路北湾至转石梁段发育有大量黄土滑坡,具有成因复杂、危害严重、治理困难等特点,对线路运营危害极大。在野外调查、无人机航拍的基础上,综合工程勘探、遥感解译成果,运用成因机制法分析沿线黄土滑坡的成因机理,提出了有针对性的防治措施。研究表明:(1)区内黄土滑坡在平面上多呈簸箕形或长舌形,普遍具有“低滑速、短滑距、多期滑动”的特征;(2)滑坡滑体多为砂质黄土,在下伏基岩风化严重的斜坡上,滑体底部存有母岩碎块,按地质成因机理可分为牵引-溜坍型滑坡和溜坍-剪切型滑坡两类;(3)牵引-溜坍型滑坡多孕育于斜坡的中、低处(多为小型滑坡),溜坍-剪切型滑坡多发育于斜坡的较高处(多为中型滑坡);(4)在降雨作用下,斜坡上覆黄土的力学行为是两类滑坡成灾的关键,可采取“清除上覆黄土+排水+坡面防护”的防治措施。

There are a large number of loess landslides in Beiwan-zhuanshiliang section of China Zhongwei-Lanzhou Railway,which have the characteristics of complex causes,serious hazards and difficult treatment,and are harmful to the operation of the line.On the basis of field investigation and UAV aerial photography,combined with the results of engineering exploration and remote sensing interpretation,the genetic mechanism method is used to analyze the genetic mechanism of loess landslides along the line,and the corresponding prevention and control measures are put forward.The results show that:(1)the Loess Landslides in the area are mostly dustpan shaped or long tongue shaped in plane,and generally have the characteristics of“low sliding speed,short sliding distance and multi-stage sliding”;(2)the landslide bodies are mostly sandy loess.On the slopes with serious weathering of underlying bedrock,there are parent rock fragments at the bottom of the landslide bodies,which can be divided into traction-sliding type and sliding-shear type according to the geological genesis mechanism;(3)Traction-slide type landslides are mostly gestated in the middle and low parts of the slope(mostly smallscale landslides),and slide-shear type landslides are mostly developed in the higher parts of the slope(mostly medium-sized landslides).(4)under the effect of rainfall,the mechanical behavior of the Loess on the slope is the key to the two types of landslides,so the prevention and control measures of“removing the overlying loess+drainage+slope protection”can be taken.