Reactivation Deformation Mechanism of Ancient Landslide at a Hydropower Station in Southeast Asia
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摘要: 针对东南亚某水电站坝址区上游右岸古滑坡,通过钻探、地质调查及长期监测研究了滑坡地层特征、滑带特征及变形特征,并对古滑坡复活机制进行探究。结果表明:(1)坡脚卸载和强降雨是古滑坡复活的主要原因;(2)道路开挖导致应力场发生改变,滑坡沿浅表部第四系坡积物和板岩、砂岩接触面“复活”,向临空面产生蠕变变形;(3)古滑坡变形与降雨呈正相关,雨季高强度降雨期间位移与变形速率急速增大,旱季无降雨时滑坡基本处于稳定状态;(4)深部位移监测数据显示,古滑坡深部未见位移突变,降雨对深部位移基本无影响。Abstract: For an ancient landslide on the upstream right bank of a hydropower station in Southeast Asia, the geological characteristics, sliding zone characteristics, and deformation characteristics of the landslide were studied through drilling, geological investigation, and long-term monitoring, and the mechanism of reactivated ancient landslide was explored. The results indicate that: (1) Unloading at the foot of the slope and heavy rainfall are the main reasons for the reactivation of ancient landslides. (2) Road excavation leads to changes in the stress field, causing landslides to "revive" along the contact surface of shallow Quaternary slope deposits, slate, and sandstone, resulting in creep deformation towards the free surface. (3) The deformation of ancient landslides is positively correlated with rainfall. During the rainy season with high intensity rainfall, the displacement and deformation rate rapidly increase, and during the dry season without rainfall, the landslide is basically in a stable state. (4) The deep displacement monitoring data shows that there is no sudden change in displacement in the deep part of the ancient landslide, and rainfall has little effect on the deep displacement.
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Key words:
- ancient landslide /
- inclination monitoring /
- apparent monitoring /
- reactivation mechanism
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表 1 H1滑坡结构及特征
层号 岩性 厚度/m 岩性特征 1 第四系坡
积碎石土0.5~7.4 主要为板岩碎石,含量约60%~70%,其余为砂质粉土,板岩碎石粒径10~40 mm、最大约50 mm,级配不良 2 板岩、炭质
板岩及砂岩3~7 滑动岩体破碎严重,岩体松动,具有弯曲揉皱、片理紊乱现象 3 G2挤压带 5~6 产状N30°~40°E/NW∠43°~58°,破碎带宽度5~6 m,由挤压片状岩、透镜体及少量糜棱岩等组成,带内岩体挤压破碎明显,局部强烈挤压后呈片理化 -
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