Abstract: In order to study hierarchy exfoliation model of bedding bank slope with intense weathering marlstone, the development of joints and fissures in marl and the strong weathering characteristics of marl in Gongjiafang bank slope were analyzed. It was believed that marl block and joint surface were the basic conditions for delamination and stripping of bank slope. A geological model which was adapted for layering-slipping, layering-dumping and layering sliding-toppling for strong weathered marl in the Three Gorges Reservoir area was proposed. Based on the static equilibrium analysis method, the mechanical model and the instable criterion of layering-slipping and layering-dumping of the rock in the bank slope were established. The study shows that the critical angle of Gongjiafang limestone block layering-slipping is 15.5° , the critical length-height ratio of layered slip instability is 2.4, and the critical contact ratio of toppling instability is 0.27.

Key words: geotechnical engineering, engineering geology, mechanism of hierarchy exfoliation, geology model, mechanical model, the Three Gorges Reservoir Region

摘要： 为研究强风化泥灰岩顺层岸坡分层剥离模式，对龚家方岸坡泥灰岩节理裂隙发育及泥灰岩强风化特性的分析，认为泥灰岩岩块与节理 面是构成岸坡分层剥离的基本条件；提出了适用于三峡库区强风化泥灰岩岸坡的分层滑移、分层倾倒和分层滑移-倾倒剥离地质模型；通过 静力平衡分析方法建立了岸坡岩块分层滑移及分层倾倒的力学模型及失稳判据。研究表明：龚家方灰岩岩块发生分层滑移的临界角度为15.5 °；分层滑移失稳的临界值长高比为2.4；倾倒失稳的临界值接触比为0.27。

关键词: 岩土工程, 工程地质, 分层剥离机理, 地质模型, 力学模型, 三峡库区