摘要
自三峡库区蓄水以来,库区不少滑坡监测位移–时间曲线呈台阶状阶跃变化,靠椅状土质滑坡尤为明显,此现象加大了滑坡稳定状态的识别度,严重影响滑坡的预警预报。以白家包滑坡为例,通过多次野外地质调查、长期现场巡查、十多年的GPS位移监测数据、1a多全自动监测数据及滑坡学相关理论等,较深入研究了在库水升降及降雨条件下该滑坡的变形演化规律。结果表明,在汛期及库水位升降时滑坡发生变形,库水位下降为诱发变形的主要因素,年位移量在35~250 mm,历年位移曲线呈"W"型波动,一次跃阶30~180 mm位移量集中在20~30 d完成。库水位下降25m水位高程为150m左右时,位移跃阶启动。库水位下降至145m后1周,跃阶日位移达最大值5~8mm/d。降雨只在库水位下降期间对滑坡的变形有一定的助推效果,在库水位上升期间,几乎没有影响。受靠椅状等坡体结构特征制约,在库水位升降作用下坡体会反复变形,但难以发生整体性大破坏。
Since its impoundment, the displacement-time curve of many landslides especially the chair-shaped soil ones in the Three Gorges Reservoir area has gradually changed, which makes the identification of stable state difficult and seriously affects the early warning and forecast of landslides. Based on the example of Baijiabao landslide, through many field geological surveys and long-term on-site inspections, and by use of more than 10 years of GPS displacement monitoring data, more than one year of fully automatic monitoring data and landslide theories, the deformation and evolution laws of the landslide under water fluctuations and rainfalls are studied in depth. The results show that the main factor inducing the deformation during the flood season and rise and fall of reservoir water level is the fall of reservoir waterlevel. The annual displacement is 35~250 mm, the historical displacement has a fluctuation of "W" type, and the first step of 30~180 mm of displacement is completed in about 20~30 d. When the water level of the reservoir drops by 25 m and the elevation of the water level is about 150 m, the displacement step starts. When the reservoir water level drops to 145 m, after one week the maximum displacement of the step is 5~8 mm/d. During the rise of the reservoir water level, the rainfall has no effect on the deformation of the landslide. Restricted by the structural characteristics of the chair-shaped slopes, the slope will be repeatedly deformed under the action of the rise and fall of water level, but it is difficult to cause overall damage.
作者
邓茂林
周剑
易庆林
张富灵
韩蓓
李卓骏
DENG Mao-lin;ZHOU Jian;YI Qing-lin;ZHANG Fu-ling;HAN Bei;LI ZHUO Jun(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area of Ministry of Education,China Three Gorges University,Yichang 443002,China;Hubei Key Laboratory of Disaster Prevention and Mitigation(China Three Gorges University),Yichang 443002,China;National Field Observation and Research Station of Landslides in Three Gorges Reservoir Area of Yangtze River,China Three Gorges University,Yichang 443002,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2020年第7期1296-1303,共8页
Chinese Journal of Geotechnical Engineering
基金
国家重点研发计划项目(2018YFC1504803)
国家自然科学基金项目(41502291)
防灾减灾湖北省重点实验室(三峡大学)开放基金项目(2018KJZ03)
三峡库区地质灾害教育部重点实验室基金项目(2017KDZ07)
湖北省自然科学基金面上项目(2018CFB654)。
关键词
靠椅状土质滑坡
位移跃阶
白家包滑坡
变形机制
库水位
chair-shaped soil landslide
displacement step
Baijiabao landslide
deformation mechanism
reservoir water level
