| 摘要: |
| 为研究三维压剪应力状态下完整岩石的剪切损伤破坏特征,本文采用 Rock Top -50HT全应力多场耦合三轴试验系统,对成分简单、结构均质的干燥和饱和完整大理岩进行高围压下的三轴剪切试验,获得了相应的三轴剪切应力-应变曲线和含有原岩屑碎片的剪切破坏裂隙面,分析了不同状态下三轴剪切应力作用下大理岩随围压的强度变化特征和脆延转化规律,探究了大理岩的三轴剪切破坏模式,并通过非接触式三维形貌扫试验,采用综合评价方法表征大理岩三轴剪切破坏结构面特征,量化分析了三轴剪切破坏结构面的粗糙度特征。结果表明：干燥与饱和大理岩的应力峰值、应变峰值均随围压的提高而增大,脆性评价指标随围压先增大再较小,且30 MPa为阈值。相对于干燥岩石,饱水状态下岩石的峰值剪切强度、残余强度和脆性评价指标和粗糙度参数降低,但随围压的增大影响逐渐减弱。岩样剪切面几乎都是沿轴向中段贯通破坏,表现出凹凸不平的断面形态,主剪切面附近由于应力的差异分布,伴生有少量衍生裂纹,且JRC随围压增大而逐渐减小。本研究对干燥和饱和大理岩的三轴剪切损伤模式进行了详细分析,指出在工程实践中应充分考虑围压与水化作用对岩石力学特性的综合影响。研究成果不仅为岩体工程的稳定性评估和安全设计提供了重要参考,还对进一步开展复杂地质环境下岩石力学行为的研究具有指导意义。 |
| 关键词: 大理岩 干燥与饱和状态 力学状态 脆延转化 裂隙结构面特征 |
| DOI： |
| 分类号:TU457 |
| 基金项目: |
|
| The triaxial shear test study on marble under dry and water-saturated conditions |
|
LIN Zhi-nan, Xiao Hu-sheng, WANG Jia-quan, ZHANG Wen-hai
|
|
College of Civil and Architectural Engineering,Guangxi University of Science and Technology,Guangxi Liuzhou
|
| Abstract: |
| To investigate the shear damage and failure characteristics of intact rock under a three-dimensional compressive-shear stress state, this study employs the Rock Top-50HT multi-field coupling triaxial testing system. Triaxial shear tests were conducted on simple-composition, homogeneous-structure dry and saturated intact marble under high confining pressures. The corresponding triaxial shear stress-strain curves and shear failure surfaces containing original rock debris were obtained. The study analyzed the strength variation characteristics of marble under triaxial shear stress at different confining pressures and the brittle-ductile transition patterns. Furthermore, the triaxial shear failure modes of marble were explored. Through non-contact 3D topography scanning tests and a comprehensive evaluation method, the characteristics of the triaxial shear failure surfaces of marble were characterized, and a quantitative analysis of the roughness features was conducted.The results show that both the stress and strain peak values of dry and saturated marble increase with confining pressure, while the brittleness index increases initially with confining pressure before slightly decreasing, with 30 MPa identified as the threshold. Compared to dry marble, the peak shear strength, residual strength, brittleness index, and roughness parameters of saturated marble decrease, but the impact diminishes with increasing confining pressure. The shear failure surfaces of the rock samples predominantly exhibit axial mid-section penetration, displaying rough, uneven fracture surfaces. A few secondary cracks are associated with stress distribution differences near the primary shear surface, and the JRC (Joint Roughness Coefficient) decreases as confining pressure increases. This study provides a detailed analysis of the triaxial shear damage modes of dry and saturated marble, emphasizing the importance of considering the combined effects of confining pressure and hydration on the mechanical properties of rock in engineering practice. The findings offer significant reference value for the stability assessment and safety design of rock engineering, while also providing insights for future studies on rock mechanical behavior in complex geological environments. |
| Key words: marble dry and saturated conditions mechanical state brittle-ductile transition fracture surface characteristics |
