玄武岩拉伸-双面剪切破坏特性的试验研究

Experimental Study on Failure Characteristics of Basalt under Tension and Double-sided Shear

通过分析玄武岩在不同拉应力水平下破裂面的形态特征和力学特性,研究岩石的破坏形态和强度、变形特征。结果表明,随着法向拉应力的增大,岩石由拉剪断裂变为拉伸断裂,断裂面倾角逐渐减小;岩石剪切方向的应力-应变曲线包含初始的非线性变形(抛物线)和后期的线性变形2个阶段;玄武岩的拉剪强度服从H-B强度准则;随着拉应力水平的增大,岩石剪切方向上的非线性变形模量和总变形模量先缓慢增大后平稳减小。

By analyzing the morphological and mechanical characteristics of the fracture surface of basalt under different tensile stress levels,the failure morphology and the strength and deformation characteristics of the rock are studied.The results show that,(a)with the increase of normal tensile stress,the rock changes from tension shear fracture to tension fracture,and the dip angle of fracture surface decreases gradually;(b)the stress-strain curve in rock shear direction includes two stages of initial nonlinear deformation(parabola)and later linear deformation;(c)the tensile shear strength of basalt obeys the H-B strength criterion;and(d)with the increase of tensile stress level,the nonlinear deformation modulus and the total deformation modulus in the rock shear direction first increase slowly and then decrease steadily.