摘要
自2003年蓄水以来,三峡库区已查明的滑坡或潜在滑坡高达5000余处,这些灾害对三峡水库的持续运营、大坝、航道及库区居民的安全造成了严重的威胁。通过研究滑坡的变形特征、诱发因素及失稳机制,有助于开展滑坡的稳定性评价,并构建预警预报模型。以三峡库区八字门滑坡为研究对象,综合分析降雨、库水位、人工和自动GNSS监测等数据,结合勘查资料及野外宏观巡查,研究了滑坡的变形特征及失稳机理,并确定合理的预警判据及阈值。研究表明:(1)八字门滑坡整体变形明显,处于蠕动变形阶段,滑坡变形主要集中于每年5—9月,滑坡累积曲线呈现典型的“阶跃”状变形特性。(2)滑坡的变形受斜坡结构、岩性等因素的控制,水库水位下降是滑坡变形的主要驱动因素,并与库水下降速率正相关。另外,特大暴雨和持续降雨在水位下降阶段、水库低水位运行期及水位上升期会促进滑坡变形,是滑坡的次要驱动因素。(3)通过精细化数据分析以及改进切线角法获取的八字门滑坡出现“阶跃”变形的位移速率阈值为4.6 mm/d,7 d累积降雨量阈值为60 mm,库水位阈值为159 m,库水位下降速率阈值0.4 m/d。
Since the impoundment in 2003,more than 5000 landslides or potential landslides have been identified in the Three Gorges Reservoir area,and these hazards seriously threaten the continued operation of the Three Gorges Reservoir and the safety of dams,waterways,and residents.By studying the deformation characteristics,inducing triggering factors,and instability mechanism of landslides,it is helpful to evaluate the stability of landslides and construct early warning and prediction models.Taking the Bazimen Landslide in the Three Gorges Reservoir Area as an example,the deformation characteristics and instability mechanism of the landslide are studied by comprehensively analyzing the data of rainfall,reservoir water level,manual and automatic GNSS monitoring,combined with the field macro inspection and exploration data,and the reasonable early warning criterion and threshold are determined.The research shows that:(1)The overall deformation of the Bazimen landslide is obvious and in the creep deformation stage.The landslide deformation is mainly concentrated in May to September every year,and the landslide accumulation curve presents typical“step-like”deformation characteristics.(2)The deformation of landslides is controlled by slope structure,lithology,and other factors.The decline of reservoir water level is the main driving factor of landslide deformation and is positively correlated with the decline rate of reservoir water.In addition,severe rainstorms and continuous rainfall will promote landslide deformation in the stage of water-level decline,reservoir low water level operation,and water level rise,which is the second driving factor of landslide.(3)The threshold displacement rate for step-like deformation of Bazimen Landslide is 4.6 mm/d,the threshold of 7 d cumulative rainfall is 60 mm,the threshold of reservoir water level is 159 m,and the threshold of reservoir water level decline rate is 0.4 m/d,obtained by refined data analysis and improved tangent angle method.
作者
郭飞
黄晓虎
邓茂林
易庆林
张鹏
陈建伟
陈陆军
GUO Fei;HUANG Xiaohu;DENG Maolin;YI Qinglin;ZHANG Peng;CHEN Jianwei;CHEN Lujun(National Field Observation and Research Station of Landslides in Three Gorges Reservoir Area of Yangtze River,Yichang 443002,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang 443002,China)
出处
《测绘学报》
EI
CSCD
北大核心
2022年第10期2205-2215,共11页
Acta Geodaetica et Cartographica Sinica
基金
国家自然科学基金(42007237,42107489)
湖北长江三峡滑坡国家野外观测站开放基金(2018KTL13)
土木工程防灾减灾湖北省引智创新示范基地(2021EJD026)。
关键词
八字门滑坡
阶跃
库水位
变形机理
预警模型
Bazimen landslide
step
reservoir water level
deformation mechanism
warning model
