Investigating the brittleness characteristics and damage evolution of deep rock masses under hydromechanical coupling has important significance. The variations in mechanical properties and brittleness characteristics of sandstone under different confining pressures and pore pressures were studied. Based on the stress threshold evolution and energy conversion analysis of the full stress-strain behavior characteristics of the rock, the new brittleness evaluation indexes were proposed, which effectively described the rock brittle failure mode and verified the reliability and applicability of the brittleness index. Additionally, from the perspective of rock pore micro-elements and the growth of matrix particle defects, the strain statistical damage theory was introduced to establish a rock statistical damage evolution model capable of accounting for the influence of pore pressure, thereby effectively capturing the nonlinear soft hardening of porous rocks under hydraulic coupling conditions. The correlation between rock brittleness and rock soft and hardening characteristics was reasonably expressed by constructing a new brittleness evaluation index, discovered from the relationship between rock damage parameters and brittleness characteristics. Eventually, based on the proposed nonlinear expression and statistical damage evolution model, the development trend of sandstone lateral strain is predicted well. The theoretical validation has good consistency with the experimental data and illustrates the rationality of the model.

中文翻译：

---

水力耦合作用下砂岩脆性评价及损伤演化


研究水力耦合作用下深部岩体的脆性特征及损伤演化具有重要意义。研究了不同围压和孔隙压力下砂岩力学性能和脆性特征的变化。基于岩石全应力应变行为特征的应力阈值演化和能量转换分析，提出了新的脆性评价指标，有效描述了岩石脆性破坏模式，验证了脆性指标的可靠性和适用性。此外，从岩石孔隙微元和基体颗粒缺陷生长的角度出发，引入应变统计损伤理论，建立了考虑孔隙压力影响的岩石统计损伤演化模型，从而有效捕捉非线性软损伤。水力耦合条件下多孔岩石的硬化。从岩石损伤参数与脆性特性之间的关系出发，构造新的脆性评价指标，合理地表达了岩石脆性与岩石软硬特性之间的相关性。最终，基于所提出的非线性表达式和统计损伤演化模型，很好地预测了砂岩侧向应变的发展趋势。理论验证与实验数据具有良好的一致性，说明了模型的合理性。