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Hoek-Brown(H-B)屈服准则存在奇异性,在岩石(体)应力状态的低(拉)围压区存在低估岩石抗拉强度的现象。为了在数值计算中处理H-B屈服准则的奇异性,解决H-B屈服准则在低(拉)围压条件下低估岩石抗拉强度的问题,采用主应力回映算法和不同应力状态选取不同的m_i常数的方法,建立基于H-B屈服准则和考虑岩石屈服前的非线性特性的本构模型;在Ls-dyna的自定义材料接口程序中利用Fortran对模型进行二次开发,通过删除单元的方法模拟岩石试件的破裂过程,实现带破坏模式的低围压条件下的模型精确数值求解,获得岩石单轴压缩与巴西劈裂的三维破坏形态;岩石单轴压缩实验、巴西劈裂实验和声发射实验的三种力学特性实验结果与模型数值计算结果比较表明,实验结果与数值计算结果吻合较好,模型及其算法有较高的准确性。
The Hoek-Brown (H-B) yield criterion has singularity and underestimates the tensile strength of the rock in the low (confined) confining pressure zone of the rock (body) stress state. In order to deal with the singularity of HB yield criterion in numerical calculation and to solve the problem that HB yield criterion underestimates the tensile strength of rock under low confining pressure, the principal stress mapping algorithm and different stress states are adopted to select different m_i constants Method to establish the constitutive model based on the HB yield criterion and considering the non-linear characteristics of the rock before yielding. In the custom material interface program of Ls-dyna, the model was re-developed with Fortran, and the rock specimen And the three-dimensional failure modes of rock uniaxial compression and Brazil rift were obtained. The rock uniaxial compression experiment, Brazilian splitting experiment and acoustic emission experiment three The comparison between the experimental results of mechanics characteristics and the numerical results of the model shows that the experimental results are in good agreement with the numerical results and the accuracy of the model and the algorithm is high.