摘要
在全球气候变暖背景下,青藏工程走廊沿线多年冻土区热融滑塌现象频发,且其数量和面积在不断增加、扩大。目前,热融滑塌的提取方法主要依赖光学遥感目视解译或深度学习模型,对处于发育初期、没有明显形态特征的隐患点识别能力有限,相关研究相对匮乏。本文基于2023年的Sentinel-2A卫星影像数据,准确识别了青藏工程走廊北麓河与五道梁镇西侧丘陵山地至错达日玛带的热融滑塌边界,建立热融滑塌发育条件阈值。同时,基于2018—2023年Sentinel-1A数据,利用SBAS-InSAR技术分析研究区形变特征,进行隐患点识别。结果表明,研究区存在622处热融滑塌,总面积12.507 km^(2)。热融滑塌的孕灾条件为海拔4700~4900 m,坡度2°~12°,NDVI(归一化植被指数)为0~0.3,FVC(植被覆盖度)为0.4~0.6,MAGT(年平均地温)为-3~-1.5℃,VWC(地下冰融化后的平均体积含水量)为30%~40%,ALT(多年冻土活动层厚度)为1~2 m的高寒草原区的北坡。研究区共识别出124处隐患点,总面积为3.12 km^(2)。其中,北麓河地区有隐患点47处,五道梁地区有隐患点77处。小型隐患点表现出更高的年平均沉降速率,预示其可能率先演化为热融滑塌的风险更高。形变曲线分析表明,处于活跃扩展阶段的滑塌年均垂直位移差达(-18±2.3)mm,且滑塌后壁顶部发育有11~15 mm·a^(-1)的高速沉降带,前缘堆积区有4~7 mm·a^(-1)的抬升变形。隐患点表现出局部变形速率较大、周围稳定的特点,地表累积沉降量较已发生的热融滑塌小,约为80 mm,地表呈现周期性下沉,具有演变为热融滑塌的高风险潜力。研究结果可为青藏工程走廊热融灾害的早期预警、生态环境保护及工程设施的安全运维提供科学依据。
Driven by the dual forces of global climate warming and intensified human activities,the degradation rate of permafrost on the Qinghai-Xizang Plateau is accelerating.This trend is particularly pronounced within the Qinghai-Xizang Engineering Corridor,where retrogressive thaw slumps(RTS)occur frequently and continue to expand.The development of RTS poses serious threats to the ecological environment and the safety of infrastructure within the corridor.Currently,methods for extracting RTS predominantly rely on visual interpretation of optical remote sensing imagery or deep learning models.However,these approaches demonstrate limited capability in recognizing potential hazard points that are in the early stages of development and lack conspicuous morphological characteristics.Research in this domain remains relatively insufficient.This study utilized Sentinel-2A satellite imagery acquired in 2023 to accurately delineate the boundaries of RTS in Beiluhe and the section extending from the hilly and mountainous areas west of Wudaoliang Town to the Cuodarima within the Qinghai-Xizang Engineering Corridor.By integrating multi-factorial disaster-inducing factors—including topography,vegetation,and permafrost—the developmental characteristics of RTS were analyzed,and thresholds for developmental conditions of RTS were established.Meanwhile,InSAR(interferometric synthetic aperture radar)data from Sentinel-1A,spanning 2018 to 2023 and collected via ascending and descending orbital passes in multi-temporal phases,were employed to analyze the deformation characteristics across the study area.By integrating disaster-inducing factors for RTS development,potential hazard points were identified.Typical sites of existing RTS and potential hazard points were then selected to analyze their deformation characteristics.The results showed that there were 622 RTS occurrences in the study area,with a total area of 12.507 km^(2)(the maximum area was 0.29 km^(2)and the average area was 0.02 km^(2)).The disaster-inducing conditions for RTS development were north-facing slopes in alpine steppe regions at an elevation of 4700 to 4900 meters,with slope gradients between 2°and 12°,normalized difference vegetation index(NDVI)values from 0 to 0.3,fractional vegetation cover(FVC)between 0.4 and 0.6,mean annual ground temperature(MAGT)spanning-3 to-1.5°C,volumetric water content(VWC)of 30% to 40%,and active layer thickness(ALT)measuring 1 to 2 meters.In the study area,124 potential hazard points were identified,with a total area of 3.12 km^(2)(the maximum area was 0.22 km^(2)and the average area was 0.0252 km^(2)).Among them,47 potential hazard points were located in the Beiluhe area,and 77 within the Wudaoliang zone.Smaller hazard points exhibited relatively higher annual average settlement rates,indicating a greater likelihood of these areas evolving into active RTS in the near future.Deformation curve analysis demonstrated that RTS in an active expansion phase showed an annual average vertical displacement rate of approximately(-18±2.3)mm,with cumulative settlement exceeding 100 mm.Additionally,a high-velocity settlement zone was observed at the crown of the headscarp,with rates between 11 and 15 mm·a^(-1).The frontal accumulation zone exhibited uplift deformation ranging from 4 to 7 mm·a^(-1).Potential hazard points,in contrast,exhibited relatively high localized deformation rates while the surrounding terrain remained stable.Their cumulative surface settlement was about 80 mm—less than that observed at established RTS sites,and the surface showed periodic settlement,indicating a high-risk potential of evolving into RTS.The findings can provide a scientific basis for early warning systems for RTS disasters within the Qinghai-Xizang Engineering Corridor,contribute to ecological environment protection efforts,and inform the safe operation and maintenance of engineering infrastructure.
作者
何人杰
刘文惠
李琼
杨莎
罗炳楠
李晴
李恬恬
张建强
杨贺铭
HE Renjie;LIU Wenhui;LI Qiong;YANG Sha;LUO Bingnan;LI Qing;LI Tiantian;ZHANG Jianqiang;YANG Heming(School of Geological Engineering,Qinghai University,Xining 810016,China)
出处
《冰川冻土》
2025年第5期1475-1489,共15页
Journal of Glaciology and Geocryology
基金
青海大学科研实力提升专项(2025KTSA03)资助。
关键词
热融滑塌
SBAS-InSAR技术
发育条件
隐患点识别
青藏工程走廊
retrogressive thaw slump
SBAS-InSAR technology
developmental conditions
identification of potential hazard points
Qinghai-Xizang Engineering Corridor
