三轴压缩条件下单裂隙岩石的破坏特性研究

通过在高强硅粉砂浆材料模型中预制特定倾角和特定尺寸的单裂隙，以常规三轴压缩试验为手段，研究单裂隙试样的破坏特性。试验中观察到3类典型的裂纹，即拉伸型裂纹（Ⅰ型）、滑移型裂纹（Ⅱ型）和撕开型裂纹（Ⅲ型），其中Ⅱ型、Ⅲ型裂纹在三维试验中普遍存在，Ⅰ型裂纹仅在部分试件中观察到；三轴压缩条件下试样的破裂模式有3种，即拉剪复合破坏、“X”型的剪切破坏和沿裂隙面的剪切破坏。试验结果表明：三轴压缩条件下的单裂隙试样的裂隙扩展规律与预制裂隙关系密切，围压是试样宏观破裂模式的主要影响因素，预制裂隙长度主要影响裂隙扩展的规模，预制裂隙倾角则是新裂隙起裂的诱因。

Experimental study of failure characteristic of single jointed rock mass under triaxial compression tests

A series of high-strength silicon powder mortar material model specimens with single joint which containing the specific size and the particular inclination are made in the laboratory, the failure modes and characteristics of the single jointed specimens are researched by means of the conventional triaxial compression test. Three typical cracks are observed during the test; they are stretching mode crack (Ⅰ), sliding mode crack (Ⅱ), tearing mode crack (Ⅲ). Ⅱ, Ⅲ cracks are ubiquitous and Ⅰcrack is only local existing. The main failure modes are X-shaped shear failure; and the pure shear failure mode is found under specific conditions. The results show that: the expanding regularity of fault cracks has close ties with the preexisting fissures; the confining pressure is the main influencing factors that the failure modes of the single jointed specimens under the conventional triaxial compression test; the preexisting length mainly affect the size of the fracture extension and joint inclination is the cause of the crack initiation.