基于数字图像的不同倾角节理灰岩破裂模式及细观尺度破裂过程研究1)

FAILURE MODE AND MESOSCALE FAILURE PROCESS OF JOINT LIMESTONE WITH DIFFERENT DIP ANGLES BASED ON DIGITAL IMAGE1)

  • 摘要: 为研究节理倾角对灰岩破裂模式及破裂过程的影响,使用数字图像对灰岩的细观非均匀性进行表征,采用岩石破裂过程分析系统(RFPA2D-DIP)对不同倾角节理灰岩的细观破裂过程及宏观破坏模式进行了研究。结果表明,细观结构对各倾角节理试样的力学特性和最终破坏模式有重要影响,含节理灰岩的弹性模量及抗压强度具有明显的各向异性,随着节理倾角的增大均呈U型变化;含节理灰岩在单轴压缩条件下以拉伸破坏为主并伴随少量剪切破坏,细观拉伸破裂的聚集导致了宏观剪切带的形成;含节理灰岩的最终破坏模式随着方位角\alpha的不同表现出6种形式:直线形(\alpha =45^\circ,\alpha=75^\circ);N形(\alpha =60^\circ);斜Z形(\alpha=0^\circ);斜N形(\alpha =90^\circ);M形(\alpha=15^\circ);V形(\alpha =30^\circ)。

     

    Abstract: In order to study the influence of the joint digital image processing (DIP) angle on the fracture mode and the fracture process of limestone, digital images are used to characterize the microscopic non-uniformity caused by the shape, the size and the distribution of the calcite in limestone. RFPA2D-DIP is used to simulate the fracture process and the failure mode of the jointed limestone with different dip angles. The results show that the meso structure has an important influence on the mechanical properties and the ultimate failure mode of the jointed specimens. The elastic modulus and the compressive strength of the jointed limestone have obvious anisotropy, and show shaped changes with the increase of the jointed dip angle. Under the action of the uniaxial compression, the jointed limestone is mainly subjected to the tensile failure accompanied with a small amount of shear failure on the mesoscale. The ultimate failure modes of the jointed limestone are shown in six forms depending on the jointed dip angle: the linear shape (\alpha =45^\circ, \alpha =75^\circ), the N shape (\alpha=60^\circ), the oblique Z shape (\alpha =0^\circ), the oblique N shape (\alpha =90^\circ), the M shape (\alpha =15^\circ), and the V shape (\alpha =30^\circ).

     

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