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岩石具有黏结和摩擦特性,但两者在同一位置并不同时存在。裂隙摩擦力随围压增加,达到邻近完整岩石黏结力后将不再滑移引起材料破坏,影响试样强度的裂隙倾角范围随之减小,引起强度非线性增加。主控裂隙引起强度在低围压下线性变化,但不能以Coulomb准则直接确定岩石的内摩擦角。砂岩内存在多种倾角的自然裂隙,引起单轴压缩及低围压的强度离散,围压增高裂隙影响减小,强度随围压规则变化而以指数准则描述;轴向压缩塑性变形引起大理岩黏结力由低向高逐步丧失,而热力损伤引起黏结力整体降低;冻结使岩石黏结力提高而内摩擦角不变。若岩石具有宏观各向同性特征,则常规三轴强度可用指数准则描述,据其确定的初始围压影响系数可估计裂隙摩擦系数;进而理解裂隙对试样强度影响的非线性特征,评价岩石材料的真实黏结力和损伤。
Rock has the characteristics of bonding and friction, but both do not exist at the same time in the same place. The fracture friction increases with the confining pressure, and will not cause the material damage after reaching the complete rock adhesion force. The fracture inclination range that affects the strength of the sample decreases, causing the nonlinear increase of the strength. The strength induced by the main fissures varies linearly with low confining pressure, but the internal friction angle of the rock can not be directly determined by the Coulomb criterion. The natural fractures with many dip angles exist in the sandstone, which cause the uniaxial compressions and low confining pressure to disperse. The influence of the confining pressure increasing fractures decreases. The intensity changes with the confining pressure rules and is described by the exponential criterion. The axial compressive plastic deformation causes the marble The cohesive force gradually decreases from low to high, while the thermal damage causes the overall cohesive force to decrease. The freezing increases the cohesion of the rock without changing the internal friction angle. If the rock has the characteristics of macroscopic isotropy, the conventional triaxial strength can be described by the exponential criterion, and the initial coefficient of confining pressure can be used to estimate the friction coefficient of the fractured rock; then, the nonlinear characteristics of the fractured rock specimen can be understood, The real bond and damage.