非贯通节理岩体单轴压缩试验研究

Study of non-consecutive jointed rock mass under uniaxial compression

对不同节理倾角、不同节理连通率的预制节理圆柱形岩体试样进行单轴压缩试验。结果表明:试样的强度、变形特性及破坏模式与节理构造形态密切相关;在不同节理连通率下,不同角度的非贯通节理试样的力学特性均表现出各向异性特征,随着节理连通率的增大,各向异性特征越来越明显,岩体峰值强度逐渐下降,岩体在弹性阶段的最大弹性模量也逐渐降低;相应地,试件的破坏模式也变得更加复杂,随着节理连通率的增大,应力-应变曲线的斜率逐渐减小,曲线出现多个峰值,且有较明显的屈服平台;非贯通节理岩体峰值强度和弹性模量随节理连通率的非线性变化规律,可分别采用二次和三次多项式函数表示,其系数与节理倾角有关;非贯通节理试样的裂纹变化特征与节理连通率、节理倾角有着密切的联系。

A series of uniaxial compression test were conducted for the prefabricated joints cylindrical rock specimens with different joint angles and joint connectivity rates. The results show that the strength of the specimen, the deformation characteristics and failure modes are closely related to the forms of the joint structure. With different joint connectivity rate, the mechanical properties of the non-interpenetrated specimens at different angles are all shown the anisotropic features, which become more obvious along with the increase of jointed connectivity rate, and meanwhile, the peak strength of the rock mass decreases gradually and so as the maximum elastic modulus of it in the elastic stage. Accordingly, the failure modes of the specimens has become more complex, with increasing of jointed connectivity rate, the slope of stress-strain curves decreases, appearing multiple peaks and obvious yield platform. The non-linear variation of peak strength of non-interpenetrated jointed rock mass and elastic modulus with the joint connectivity rate can be expressed by quadratic and cubic polynomial functions respectively, determining coefficients associated with the joint angles. The crack change features of the non-interpenetrated jointed specimens have a close relationship with joint connectivity rate and joint angles.