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采用理论分析和模型试验相结合方法,对共面闭合断续节理岩体直剪强度特性进行分析和研究.引入法向变形协调条件,基于Mohr-Coulomb理论,推导共面断续节理岩体模型的直剪强度公式.模型试验表明:全应力-应变曲线主要经历了线弹性增长、节理面错动、次生裂纹起裂稳态扩展、节理面贯通破坏和残余强度5个阶段;剪切应力峰值和残余强度都随正应力的增大而增大,而变形特性随正应力的变化规律性不强;抗剪峰值强度随节理连通率的增大而减小,低连通率时强度下降速度慢;节理分布形态对强度也有影响,节理在两边分布的试样强度普遍高于节理在中间的;理论计算结果与试验值吻合较好,能较好描述共面断续节理岩体的直剪强度特征.
The method of combining theoretical analysis with model test is used to analyze and study the strength characteristics of rockfill in co-planar closed discontinuous jointed rock mass.Using the method of normal deformation and coordination and the Mohr-Coulomb theory, The results of the model tests show that the total stress-strain curve mainly undergoes five stages of linear elastic growth, joint movement, secondary crack initiation and propagation, joint failure and residual strength. Shear stress Both the peak value and the residual strength increase with the increase of normal stress, while the deformation regularity with normal stress is not strong. The peak shear strength decreases with the increase of joint connectivity rate and the strength decrease rate with low connectivity rate The distribution of the joints is also affected by the strength of the joint. The strength of the specimen distributed on both sides of the joint is generally higher than that of the joints. The theoretical calculation results are in good agreement with the experimental values, which can well describe the direct shear strength Strength characteristics.