大别造山带岳西县斜坡变形破坏演化模式

岳西县自然斜坡在地球内、外动力共同作用下,容易变形并遭到破坏,造成人员伤亡和财产损失,严重制约了当地的经济发展。通过系统的工程地质调查和浅表生改造理论分析,查明了岳西县斜坡变形破坏特征及其成因,并探讨了其演化模式。结果表明,岳西县不同岩组的抗风化能力和力学特性存在差异,斜坡发生地质灾害的机理也不相同。根据斜坡结构特征,岳西县滑坡分为全风化层滑坡、强风化层滑坡和顺层岩质滑坡: 全风化层滑坡的滑面位于全风化层中或全风化层与强风化层的分界线处; 强风化层滑坡的滑面主要发育于强风化层与中风化层的分界线处; 顺层岩质滑坡主要发育于片麻岩发育的顺向坡中。根据变形破坏方式,岳西县崩塌可分为滑移式崩塌、倾倒式崩塌和坠落式崩塌: 滑移式崩塌主要由一组缓倾坡外结构面和另一组陡倾(坡外或者坡内)结构面控制; 倾倒式崩塌主要由一组陡倾坡内结构面和另一组近水平发育的结构面控制; 坠落式崩塌主要由一组结构面陡倾或近直立发育的结构面控制。岳西县滑坡多发育于风化壳厚度较大、岩体较松散、结构面强度低的地区; 崩塌多发育于斜坡高陡、岩质风化程度低、结构面发育的地区。研究成果对岳西县乃至整个大别山地区地质灾害的研究及防治工作具有一定的借鉴意义。

Evolution model of slope deformation and failure in Yuexi Country of Dabie mountains orogenic belt

The natural slopes in Yuexi County are prone to deformation and failure under the combined action of the earth’s internal and external forces, causing casualties and property loss, which seriously restricts the development of local economy. The characteristics and causes of slope deformation and failure in Yuexi Country were identified through systematic engineering geological survey and theoretical analysis, and the evolution model was discussed. The results show that the weathering resistance and mechanical properties of different rock groups in Yuexi Country are different, so the mechanisms of the geological hazards of the slopes are also discrepant. According to the characteristics of slope structure, the landslide in Yuexi Country can be divided into all-weathered landslide, strong weathered landslide and bedding rock landslide. The sliding surface of all-weathered landslide is located in the full regolith or the interface between full regolith and strong regolith. The slip surface of strongly weathered landslide mainly develops at the interface between strong regolith and middle regolith. The bedding rock landslide is mainly developed in the down-slope of gneiss. The collapse in Yuxi Country can be divided into sliding collapse, toppling collapse and falling collapse, according to the deformation and failure model. The sliding collapse is mainly controlled by a group of gently sloping external structural planes and another group of steeply sloping (external or internal) structural planes. The toppling collapse is mainly controlled by one set of structural planes in steep slopes and another set of near-horizontal structural planes. Falling collapse is mainly controlled by a set of structural planes which are steeply inclined or nearly erect. Landslides in Yuexi Country are mainly developed in areas with thick weathering crust, loose rock mass and low structural plane strength. Collapses are mainly developed in areas with high and steep slopes, low degree of rock weathering and structural plane development. This research has some guiding effect on the investigation and prevention of geological hazards in Dabie mountains and Yuexi Country.