伊犁苏阿苏沟东岸黄土滑坡群发育特征及成因分析

Development Characteristics and Genesis of Loess Landslides on the East Bank of Asuligou,Yili

黄土滑坡及次生灾害是新疆伊犁谷地最普遍和典型的灾害类型,具分布最广、发生频率最高、危害性最大的特点。以伊犁苏阿苏沟东岸黄土滑坡群为研究对象,通过现场勘察获取岩土体形态特征和力学参数,确定岩土体结构和发育特征,并对成因进行分析。研究表明:该滑坡群为“黄土+砂砾石+软岩(泥岩)”结构模式,滑体由第四系黏砂土和卵石夹黏土组成,滑床为中侏罗统西山窑组泥岩,二者接触带为滑动面,属层内错动,呈多级或局部滑动。滑体上部裂缝以横向裂缝为主,下部以放射状裂缝为主,于滑坡前缘形成鼓丘。该滑坡成因类型为浅层牵引式滑坡,季节性降水和冰雪融水为发生滑坡的主导因素。

The loess landslide and its secondary disasters are the most common and typical disaster types in the Yili Valley of Xinjiang,with the characteristics of the widest distribution,the highest frequency and the most harmful.In this paper,the loess landslide group on the east bank of Asuligou in Ili is taken as the research object.The morphological characteristics and mechanical parameters of the rock and soil mass are obtained through site survey,and the structure and development characteristics of the rock and soil mass are determined.Studies have shown that the landslide group is a structure model of"loess+gravel+soft rock(mudstone)".The landslide is composed of Quaternary subsand soil and pebble with clay.The sliding bed is mudstone of the Middle Jurassic Xishanyao Formation.The contact surface of the two has sliding surfaces,which are distorted within the layer and slide in multiple stages or parts.The cracks in the upper part of the landslide are mainly transverse cracks,and the lower part is mainly radial cracks.Drum mounds are formed at the leading edge of the landslide.The cause of the landslide is a shallow traction landslide.Seasonal precipitation and melting snow and ice are the dominant factors in the occurrence of landslides.