冻融循环作用下伊犁黄土性质劣化特征及其对滑坡稳定性的影响

DETERIORATION CHARACTERISTICS OF ILI LOESS PROPERTIES UNDER FREEZE-THAW CYCLES AND THEIR INFLUENCE ON LANDSLIDE STABILITY

新疆伊犁地区作为我国西北地区气候较敏感区域之一,地质灾害较发育,且地质灾害具有危险性严重、危害程度大、成灾速度快等特点,对社会经济发展影响巨大。为加强地质灾害防治,构建安全的生产生活环境,本文以伊犁地区新源县阿勒马勒镇黄土滑坡为研究对象,综合利用野外地质调查、现场取样、室内试验分析等方法,分析了该地区黄土在冻融循环作用下其强度变化的特征以及对滑坡稳定性的影响。结果表明,随着冻融循环次数的增加,滑坡土体强度出现不同程度劣化,与此同时,滑坡稳定性变化趋势也与土体强度劣化趋势一致。分析认为,在冻融循环作用下,黄土空间结构出现不同程度破坏,造成土颗粒级配及接触类型发生变化,使得土体强度出现不同程度的衰减。滑坡整体稳定性受冻融作用的影响而产生变化,在经历3次冻融循环以后,滑坡稳定性发生突变,之后滑坡长期处于蠕滑状态。在此过程中,黄土滑坡变形失稳区域主要集中在滑坡浅层,变形贯穿区域仅限于上层冻结区域土层,不易出现中深层滑坡,滑坡变形程度较轻。研究成果可为新疆伊犁地区地质灾害防灾减灾提供参考价值,也可为类似地区的黄土滑坡地质灾害研究提供参考。

As one of the more sensitive climatic regions in northwest China,the Ili region of Xinjiang has more developed geological hazards.The geological hazards are characterized by serious hazards,high degree of danger and rapid disaster formation,which have great impact on social and economic development.In order to strengthen the prevention and control of geological hazards and build a safe production and living environment,this paper takes the loess landslide in Almal Town,Xinyuan County,Ili Region as the research object.It analyses the characteristics of the strength change of the loess in the area under the action of freeze-thaw cycle and the influence on the stability of the landslide using field geological survey,field sampling and indoor test analysis.The results of the study showed that the strength of the landslide soil deteriorated to different degrees as the number of freeze-thaw cycles increased,while the trend of landslide stability was also consistent with the deterioration of soil strength.The analysis suggests that the spatial structure of the loess is damaged to varying degrees by the freeze-thaw cycles,resulting in changes in soil particle gradation and contact type,which causes the soil strength to deteriorate to varying degrees.The overall stability of the landslide is affected by the freeze-thaw action and changes.After three freeze-thaw cycles,the stability of the landslide changes abruptly,after which the landslide is in a long-term creep-slip state.During this process,the deformation and destabilisation area of the loess landslide is mainly concentrated in the shallow layer of the landslide,and the deformation penetration area is limited to the upper frozen area soil layer,which is not easy to occur in the middle and deep layers,and the degree of landslide deformation is relatively light.The research results can provide reference value for the prevention and mitigation of geological disasters in the Ili region of Xinjiang,and provide guidance for the study of geological disasters of loess landslides in similar areas.