摘要
随着全球气候变暖和人类活动的增加,青藏高原滑坡、热融滑塌、融冻泥流等斜坡地质灾害事件频发。其中位于青藏高原东缘的共和—玉树段高等级公路沿线发育大量斜坡地质灾害,对区内基础设施的建设和安全运营造成严重威胁。但是,目前对公路全线不稳定斜坡的分布规律和影响因素仍不明晰,严重制约了公路的建设和发展。因此,本研究基于IPTA-InSAR技术对共和—玉树段高等级公路沿线开展了地表变形监测、不稳定斜坡早期识别和野外验证,总结不稳定斜坡的分布特征及类型,探讨不稳定斜坡变形影响因素。结果表明:研究区降轨雷达视线方向地表变形速率在-249~335 mm·a^(-1)的范围内,研究区整体较稳定,在多格茸盆地及巴颜喀拉山附近出现大面积地面抬升现象。基于InSAR变形监测结果,共解译识别出974处不稳定斜坡。不稳定斜坡分布广泛,主要集中在河卡山至温泉乡段和清水河镇至玉树段,玛多县和野牛沟附近有少量分布。不稳定斜坡类型主要包括:蠕变型斜坡、堆积层滑坡、基岩滑坡。其中,1处大型的基岩滑坡位于温泉乡青根河边,该滑坡的发育受到构造作用的控制,在降雨和河流侵蚀的作用下,坡体发生滑动,后期可能会堵塞青根河,形成堰塞湖、溃坝等灾害链灾害。1处堆积层滑坡位于河卡山山区,该滑坡主要受到降雨及气温的影响,冻融作用的不断持续及反复导致堆积层表面出现大量裂隙,降水通过裂隙改变堆积层底部的热状态,促使基岩表面的地冰融化,形成滑动面,融水同雨水冲刷搬运堆积层滑动,同时,坡体下部沟道底部的滑动牵引中部发生滑动。蠕变型斜坡972处,在全线均有分布,1处典型蠕变型斜坡位于河卡山附近,该斜坡位于小流域集水区,常年含水或含冰量很高,在修路开挖扰动的影响下,地下冰层暴露融化,底部物质遇水饱和后,土体结构破坏导致孔隙水压力升高,抗剪强度降低,形成软弱的滑动面引发边坡破坏,后期可能逐渐演化为其他灾害类型。研究区不稳定斜坡的变形主要受草地、荒漠地区土壤松散特性的控制,降雨量增加和气温变化是不稳定斜坡发生变形的直接驱动因素。本研究揭示了共和—玉树段高等级公路斜坡地质灾害的发育特征和影响因素,为公路风险防控和安全运营提供科学支撑。
With global warming and increasing human activities,slope geohazards such as landslides,thaw col⁃lapse,and gelifluctions have become increasingly frequent on the Qinghai-Xizang Plateau.A large number of slope geohazards have developed along the Gongyu High-grade Highway on the eastern edge of the Qinghai-Xizang Plateau,posing serious threats to infrastructure construction and safe operation in the region.However,the distribution patterns and factors influencing unstable slopes along the entire highway remain unclear,which severely constrains the construction and development of highways.Using IPTA-InSAR technology,this study conducted surface deformation monitoring,early-stage identification of unstable slopes,and field validation along the Gongyu High-grade Highway.Then,the spatial distribution and types of unstable slopes were summa⁃rized,and their influencing factors of deformation were analyzed.The results showed that the surface deforma⁃tion rate along the radar line-of-sight direction in the study area ranged from-249 to 335 mm·a^(-1).The overall ar⁃ea remained relatively stable,with significant surface uplift observed near the Duogerong Basin and Bayan Har Mountains.Based on the InSAR deformation monitoring results,a total of 974 unstable slopes were identified.Unstable slopes were widely distributed in the study area,mainly concentrated in the Heka Mountain to Wen⁃quanxiang segment and Qingshuihe County to Yushu segment,with minor distributions near Maduo County and Yeniugou.Types of unstable slopes included creep,colluvial landslides,and bedrock landslides.Among them,one large-scale bedrock landslide was located along the Qinggenhe in Wenquanxiang.The development of this landslide was structurally controlled.Under the influence of rainfall and river erosion,the slope experienced slid⁃ing.In the future,it may block the Qinggen River,potentially triggering disaster chain effects such as barrier lake and dam break.One colluvial landslide was located in the mountainous area of Heka Mountain,mainly in⁃fluenced by rainfall and temperature.The persistent and cyclic freeze-thaw actions caused extensive cracks on the slope surface.Precipitation infiltrated through cracks,altering the thermal state at the base of the colluvium and promoting ground-ice melting on the bedrock interface.This process formed a sliding surface.Meltwater and rainwater further eroded and transported the colluvium,triggering sliding.Additionally,the sliding of the lower gully channel at the slope’s toe exerted a retrogressive pull,causing the middle section of the slope to slide.There were 972 creep slopes distributed along the entire highway.One typical creep slope was located near the Heka Mountain.This slope was located in a small watershed catchment area with consistently high wa⁃ter or ice content.Under the influence of road construction and excavation disturbances,the underground ice lay⁃er was exposed and gradually melted.As the underlying materials became saturated with water,the soil struc⁃ture was damaged,leading to an increase in pore water pressure and a reduction in shear strength.This resulted in the formation of a weak sliding surface,triggering slope failure.In the future,this landslide may gradually evolve into other types of geohazards.The deformation of unstable slopes in the study area is primarily con⁃trolled by the loose soil characteristics of grassland and desert areas.Increased rainfall and temperature varia⁃tions serve as the direct driving factors for slope deformation.This study reveals the development characteristics and influencing factors of slope geohazards along the Gongyu High-grade Highway,providing scientific support for risk prevention,hazard control,and the safe operation of the Gongyu High-grade Highway.
作者
马开启
张毅
孟兴民
刘旺财
李恒源
李媛茜
王爱杰
黄逢春
吴向
MA Kaiqi;ZHANG Yi;MENG Xingmin;LIU Wangcai;LI Hengyuan;LI Yuanxi;WANG Aijie;HUANG Fengchun;WU Xiang(School of Earth Sciences,Lanzhou University,Lanzhou 730000,China;Gansu Technology&Innovation Centre for Environmental Geology and Geohazards Preventio,Lanzhou 730000,China)
出处
《冰川冻土》
2025年第4期887-899,共13页
Journal of Glaciology and Geocryology
基金
甘肃省重点研发计划项目“震后滑坡灾害风险动态评估与防控技术研究”(24YFFA005)
第二次青藏高原综合科学考察研究项目(SQ2021QZKK0201)资助。
