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巷(隧)道围岩的显著特点为破裂后承载,破裂围岩强度及变形特征的正确评价对其围岩稳定控制意义明显。以从已破坏返修段巷道现场采集的破裂岩样为研究对象,根据其现场多处于近似零围压或低围压的应力环境,借助MTS伺服试验机对其单轴压缩下再破坏时的强度及变形特征进行系统研究。结果表明:破裂面对岩石的峰值强度产生明显的影响,对残余强度无直接决定性的影响;破裂岩样全应力-应变曲线总体可分为单峰型和多峰型2类;破裂面对岩石的割线模量及泊松比、峰值轴向应变影响不明显,但对峰值环向及体积应变影响明显;破裂岩样破裂面扩展过程及最终的破坏模式与原主破裂面的角度有关,主破裂面与加载方向近乎平行时,多发生竖向劈裂破坏,当两者垂直时,多发生竖向劈裂与横向主破裂面贯通破坏,其他情况大多发生竖向劈裂与剪切组合破坏模式;破裂岩样表面破裂面分布具有明显的分形特征,且其单轴压缩峰值强度与其表面破裂面盒维数两者之间总体符合线性单调减函数关系。
The significant features of the tunnel (tunnel) tunnel are that the correct evaluation of the strength and deformation characteristics of the bearing and rupturing surrounding rock after fracture is of great significance to the stability control of the surrounding rock. The fractured rock samples collected from the damaged repaired section tunnel are taken as the research object. According to the stress environment that the site is near zero confining pressure or low confining pressure, the strength of the MTS servo testing machine under its uniaxial compression And deformation characteristics of systematic research. The results show that the fracture surface has obvious influence on the peak strength of rock and has no direct and decisive influence on the residual strength. The total stress-strain curve of the fracture can be divided into two types: unimodal and multi-peak, The secant modulus, Poisson’s ratio and peak axial strain have no significant effect on the peak circumferential strain and volumetric strain, but the influence of peak secant and volumetric strain is significant. The process of fracture surface rupture and the final failure mode are related to the original rupture plane. When the fracture surface and the loading direction are almost parallel, the vertical splitting failure occurs frequently. When the two are vertical, the vertical splitting and the transverse main rupture surface break through. In most other cases, the vertical splitting and shearing combination destroy Mode. The fractured surface distribution of fractured rock samples has obvious fractal characteristics, and the uniaxial compressive peak intensities and the fractal surface fractal dimension of the fractured rock surface all fit the linear monotonous decreasing function.