A FORTRAN program, consistent with the commercially available finite element (FE) code ABAQUS, is developed based on a three‐dimensional (3D) linear elastic brittle damage constitutive model with two damage criteria. To consider the heterogeneity of rock, the developed FORTRAN program is used to set the stiffness and strength properties of each element of the FE model following a Weibull distribution function. The reliability of the program is assessed against available experimental results for granite cylindrical specimens with a throughgoing, flat and inclined fissure. The calibration procedure of the material parameters is explained in detail, and it is shown that the compressive to tensile strength ratio can have a substantial influence on the failure response of the specimens. Numerical simulations are conducted for models with different levels of heterogeneity. The results show a smaller load bearing capacity for models with less homogeneity, representing gradual coalescence of fully damaged elements forming throughout the models during loading. The maximum load bearing capacity is studied for various combinations of inclination angles of two centrally aligned, throughgoing and flat fissures of equal length embedded in cylindrical models under uniaxial and multiaxial loading conditions. The key role of the compressive to tensile strength ratio is highlighted by repeating certain simulations with a lower compressive to tensile strength ratio. It is proven that the peak loads of the rock models with sufficiently small compressive to tensile strength ratios containing two throughgoing fissures of equal length are similar, provided that the minimum inclination angles of the models are the same. The results are presented and discussed with respect to the existing experimental findings in the literature, suggesting that the numerical model applied in this study can provide useful insight into the failure behaviour of rock‐like materials.

中文翻译：

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既有裂隙受压岩石试样裂缝扩展的三维有限元模拟及其强度分析

基于具有两个损伤标准的三维（3D）线性弹性脆性损伤本构模型，开发了与市售有限元（FE）代码ABAQUS一致的FORTRAN程序。为了考虑岩石的非均质性，开发的FORTRAN程序用于遵循Weibull分布函数设置FE模型的每个元素的刚度和强度属性。该程序的可靠性是根据具有贯穿，平坦和倾斜裂缝的花岗岩圆柱试样的现有实验结果评估的。详细说明了材料参数的校准程序，结果表明抗压强度与拉伸强度之比可能会对试样的失效响应产生重大影响。对具有不同异质性水平的模型进行了数值模拟。结果表明，同质性较低的模型的承载能力较小，这表示在加载过程中整个模型中形成的完全损坏的元素逐渐合并。研究了在单轴和多轴载荷条件下，圆柱模型中嵌入的等长的两个中心对齐，直通和扁平裂缝的倾角的各种组合的最大承载能力。通过以较低的压缩抗拉强度比重复​​某些模拟，突出了压缩抗拉强度比的关键作用。事实证明，抗压强度与抗拉强度之比足够小且包含两个相同长度的贯穿裂缝的岩石模型的峰值载荷是相似的，只要模型的最小倾斜角度相同即可。结合文献中已有的实验结果对结果进行了介绍和讨论，这表明本研究中使用的数值模型可以提供对类岩石材料破坏行为的有用见解。