Complexities in mechanical behaviours of rock masses mainly stem from inherent discontinuities, which calls for advanced bolt-grouting techniques for stability enhancement. Understanding the mechanical properties of bolt-grouted fractured rock mass (BGFR) and developing accurate prediction methods are crucial to optimize the BGFR support strategies. This paper establishes a new elastoplastic (E-P) model based on the orthotropic and the Mohr-Coulomb (M-C) plastic-yielding criteria. The elastic parameters of the model were derived through a meso-mechanical analysis of composite materials mechanics (CMM). Laboratory BGFR specimens were prepared and uniaxial compression test and variable-angle shear test considering different bolt arrangements were carried out to obtain the mechanical parameters of the specimens. Results showed that the anisotropy of BGFR mainly depends on the relative volume content of each component material in a certain direction. Moreover, the mechanical parameters deduced from the theory of composite materials which consider the short fibre effect are shown to be in good agreement with those determined by laboratory experiments, and the variation rules maintained good consistency. Last, a case study of a real tunnel project is provided to highlight the effectiveness, validity and robustness of the developed E-P model in prediction of stresses and deformations.

中文翻译：

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锚杆灌浆裂隙岩的新弹塑性模型


岩体力学行为的复杂性主要源于固有的不连续性，这需要先进的锚杆注浆技术来增强稳定性。了解锚杆灌浆裂隙岩体 (BGFR) 的力学特性并开发准确的预测方法对于优化 BGFR 支护策略至关重要。本文建立了一种基于正交各向异性和莫尔-库仑（MC）塑性屈服准则的新弹塑性（EP）模型。模型的弹性参数是通过复合材料力学（CMM）的细观力学分析得出的。制备了实验室BGFR试件，并进行了考虑不同螺栓布置方式的单轴压缩试验和变角剪切试验，以获得试件的力学参数。结果表明，BGFR的各向异性主要取决于各组分材料在某一方向上的相对体积含量。此外，由考虑短纤维效应的复合材料理论推导的力学参数与实验室实验确定的力学参数吻合较好，变化规律保持了良好的一致性。最后，提供了一个真实隧道项目的案例研究，以强调所开发的 EP 模型在预测应力和变形方面的有效性、有效性和鲁棒性。