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本文叙述了葛洲坝工程成层岩体中,层间剪切带和软岩夹层的地质结构特征、物理性质以及试验室和原位直剪试验研究成果。 对剪切带和各类软岩夹层的剪应力与剪切位移关系及其破坏形式的研究表明,软岩夹层的剪切强度和变形特性,取决于软岩与上复岩层胶结力很弱的交界面(层理面)的软岩壁面强度和粗糙度,其抗剪强度远低于软岩本身的强度。而剪切带则取决于其中粘土颗粒、粒团呈定向排列的光滑擦痕面的物理力学性质;由于岩层层理平坦、起伏度小,抗剪强度尺寸效应不太明显。 对剪切带和软岩夹层的剪应力与剪切位移关系进行了数学模拟,从中可获得各种变形参数,它们与强度参数具有良好的相关性,且变形参数对软弱层带力学性能的反应,比强度参数更为敏感。
This paper describes the geological structure characteristics, physical properties, and laboratory and in-situ direct shear test results of the strata in the Gezhouba project, the interlayer shear zone and the soft rock interlayer. The study on the relationship between shear stress and shear displacement and the failure modes of the shear zone and various types of soft rock sandwiches shows that the shear strength and deformation characteristics of the soft rock interlayer depend on the weak bonding strength between the soft rock and the upper phyllosphere. The strength and roughness of the soft rock wall at the interface (bedding plane) is much lower than that of the soft rock itself. The shear zone depends on the physico-mechanical properties of the smooth scratch surface in which the clay particles and the pellets are aligned. Because the rock layer is flat and the degree of undulation is small, the shear strength size effect is not obvious. The relationship between shear stress and shear displacement of the shear zone and the soft rock interlayer is simulated. Various deformation parameters can be obtained from them. They have good correlation with the strength parameters, and the deformation parameters respond to the mechanical properties of the soft zone. , more sensitive than strength parameters.