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节理裂隙对岩石的强度破坏及裂纹扩展特征具有显著影响.为了进一步认识预制裂隙对断续裂隙岩石力学行为的影响,本文在一组经过室内试验标定的细观参数的基础上,进行了断续三裂隙砂岩试样单轴压缩颗粒流模拟.基于模拟结果,分析了岩桥倾角对裂隙砂岩试样应力-应变曲线、强度变形参数以及裂纹扩展特征的影响.研究结果表明:(1)峰值强度、弹性模量、峰值应变、裂纹起裂应力和贯通应力均随着岩桥倾角的增大呈先减小后增大再减小变化趋势,而裂纹损伤阈值与岩桥倾角之间无明显相关性;(2)岩桥倾角主要影响中间裂隙2的起裂模式,当岩桥倾角较小时裂隙2尖端不易萌生裂纹;(3)裂纹贯通模式和程度均与岩桥倾角密切相关.当岩桥倾角为0°、30°和60°时只有2处贯通,岩桥倾角为90°和120°时发生4处贯通,而岩桥倾角为150°时有5处贯通.裂纹贯通形式主要分为7类,而且断续三裂隙砂岩贯通模式是其中一类或多类贯通形式的组合.最后,从细观应力场和位移场角度讨论了岩桥倾角较小时中间裂隙2尖端裂纹较难起裂的原因.
The joint fissures have a significant effect on the strength failure and crack propagation characteristics of the rock.In order to know more about the influence of the prefabricated fissures on the rock mechanics behavior of the fractured fissures, based on a set of mesoscopic parameters calibrated by laboratory tests, Based on the simulation results, the influence of rock slope inclination on the stress-strain curve, strength and deformation parameters and crack propagation characteristics of fractured sandstone samples was analyzed.The results show that: (1) The peak intensity, The elastic modulus, peak strain, crack initiation stress and penetration stress decrease first, then increase and then decrease with the increase of rock slope angle, but there is no significant correlation between crack damage threshold and rock slope ; (2) Inclination angle of rock bridge mainly affects the initiation mode of middle fracture 2, and the crack tip is not easy to initiate when the rock slope angle is small; (3) The mode and degree of crack through are closely related to the rock slope inclination. There are only two passes at 0 °, 30 ° and 60 °, and 4 passes at rockfill inclination of 90 ° and 120 °, whereas 5 passes at rockfill inclination of 150 °. The crack through forms are mainly divided into 7 , And the intermittent three-fractured sandstone through-mode is a combination of one or more types of through-going forms.Finally, the reason that the crack tip of the intermediate fracture 2 is more difficult to crack is discussed from the perspective of mesoscopic stress field and displacement field .