巴东新城白土坡深层岩体软弱夹层地质特征

Weak intercalated layers' geologic feature in deep-seated rock mass of Baitupo slope in Badong new town-site of the Three Gorges reservoir

巴东组第三段中的软弱夹层是白土坡斜坡的主要结构面,巴东新城白土坡深层变形监测钻孔揭露白土坡斜坡巴东组第三段厚度在270m左右,主要贯通性软弱夹层有13层,为泥质灰岩碎块石夹土、黄褐色碎石土,中上部夹层分布较密,软弱夹层的空间分布由沉积环境所决定的岩性变化控制,典型夹层露头构造分析表明夹层由于构造作用发生过层间错动,夹层的存在有利于斜坡深层变形,三峡水库蓄水后水位的抬高将会影响到斜坡岩体的深层蠕变。

Weak intercalated layers in the 3^rd Member of Badong Formation（T2 b^3 ）are the principal structural plane, 13 major penetrative weak intercalated layers within 270m thick rock mass were revealled by deep-seated deformation monitoring profiles in Baitupo slope in Badong new town-site of the Three Gorges reservoir. The weak intercalated layers are crushed stone of argillaceous limestone and ocher soil aggregate. Most of weak intercalated layers were located at middle and top part at Baitupo slope, weak intercalated layer＇s spatial distribution was controlled by the lithologic character variation decided by sedimentary environment, and intercalated dislocation was caused by tectonic process by analysing intercalated layer outcrop＇ s structures. The existence of weak intercalated layer made for slope＇s deep-seated deformation. The water level＇s uplift after the impoundment of the Three Gorges reservoir will affect rock mass＇ deep-seated creep.