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层面是层状岩体稳定性的主控结构面,层面的剪切力学行为及抗剪强度对建造于层状岩体中的地下工程具有重要影响。由于成岩时期物化作用的差异,同一工程场址常发育不同地质特征(胶结充填物、粗糙度等)的层面。为了深入了解不同类型层面的剪切力学特性,利用乌东德水电站地下厂房区域取得的胶结层面试样开展常法向应力及峰后降法向应力直剪试验。试验结果表明,不同地质特征的层面表现出不同的剪切力学行为,按有无明显峰值可将剪切变形–剪应力曲线分为2类,无明显峰值层面的粗糙度和表面附着物均有别于有明显峰值层面。法向变形与法向应力直接相关,但与层面类别之间的关系不明显。不同类型层面还表现出不同的剪胀行为及相应的剪胀角差异。胶结层面抗剪强度低于完整岩石但高于已分离层面,对层状岩体起弱化作用。按层面地质特征对其进行分类有助于进一步理解层状岩体的复杂力学行为,而选择不同层面力学模型可使计算更贴近实际工程岩体特征。
The level is the main control plane of the stability of stratified rock mass. The shear mechanics and shear strength of the strata have an important influence on the underground engineering built in the layered rock mass. Due to the different physicochemical functions during the diagenetic period, different geological features (cements, roughness, etc.) are often developed at the same project site. In order to gain a better understanding of the shear mechanics characteristics of different types of layers, normal shear stress and post-peak normal shear stress tests were carried out by using cemented samples obtained from the underground powerhouse of Wudongde Hydropower Station. The experimental results show that the different geological characteristics show different shear behavior, and the shear deformation-shear stress curves can be divided into two types according to the presence or absence of obvious peaks. There is no obvious difference between the surface roughness and surface attachments Do not have obvious peak level. Normal deformation and normal stress are directly related, but the relationship between the level of classification is not obvious. Different types of levels also showed different dilatancy behavior and the corresponding dilatancy angle difference. The shear strength of the cemented layer is lower than that of the intact rock but higher than the separated layer, weakening the layered rock mass. It is helpful to further understand the complex mechanical behavior of layered rock mass by classifying it according to the geological characteristics of the layered rock mass. Selecting different layers of mechanical models can make the calculation closer to the actual rock mass characteristics.