三峡库区巴东县新城区斜坡构造体系特征研究

Slope Structure System's Feature at New County-site Town of Badong in Three Gorges Reservoir Region

斜坡的形成及演变受到地质构造的控制,大地构造背景决定了三叠系中统巴东组地层的浅海沉积.中三叠世末期印支运动奠定了研究区的基本构造格局.长江的贯通峡谷的发育决定了巴东新城区的地貌特征,近东西走向官渡口向斜控制了巴东新城区白土坡等斜坡的总体形态,基本上是顺层岩体斜坡.巴东组第三段深部岩体共扼剪节理反映构造应力场为近SN向挤压,巴东组第三段的次级褶皱及层间错动带的发育也为前期构造成因,以白土坡为例分析了斜坡构造体系与岩体结构的关系,三峡水库蓄水后将影响巴东组第三段斜坡岩体的稳定性.图4,参11.

Slope＇s formation and evolvement were controlled by geological structure, the neritic deposit＇s character of Badong Formation of middle series of Triassic System was decided by geotectonic geology background,the fundamental tectonic framework at region of interest was established by indosinian movement at the end of middle-riassic. The geomorphic feature of new county-site town of Badong was formed by Yangtse Rive＇s break and gorge＇s development, slopes＇ shapes at new county-site town of Badong were controlled by nearly EW-striking Guandukou syncline and basically became consequene rock mass slope, a pair of conjugate shear joint measured in the cave of the 3^rd Member of Badong Formation at Baitupe slope reflected that areal tectonic stress field was approximately SN horizonal squeezing, subsidiary fold and intercalated dislocation zone were formed by prophase structure, the slope rock mass was cut by faults as analysis of Baitupe slope, The impoundment of Three Gorges reservoir will affeet rock mass＇ stability of 3rd Member of Badong Formation.