School of Civil Engineering, Shandong Jianzhu University
Laboratory of Building Structural Retrofitting and Underground Space Engineering, Ministry of Education, Shandong Jianzhu University
School of Emergency Technology and Management, North China Institute of Science and Technology
Information Institute of Ministry of Emergency Management

为研究高应力围岩扰动破坏机制,开展了不同围压下类岩石试件的三轴常规压缩和三轴循环扰动试验,得到了试件的扰动应力–应变规律和变形破坏特征,并对试件开展了核磁共振(NuclearMagneticResonance)成像试验,从微观角度进一步阐明了试件扰动破坏机理。研究结果表明:(1)试件在不同围压下均存在一个阈值强度,轴向荷载超过阈值强度后,轴向变形对扰动变得敏感,再次施加扰动会引起试件显著变形,当轴向荷载低于阈值强度时,变形对扰动不敏感。阈值强度与极限强度的比值可以反映试件的抗扰动能力,随着围压增大,该比值呈现逐步递减的规律,说明高围压下试件抗扰动能力下降,对扰动作用更敏感。(2)扰动作用下类岩石试件存在弱化效应,如常规三轴10MPa围压下试件表现出腰鼓破坏,而受扰动作用后,试件呈现斜切脆性破坏,与常规三轴5MPa围压下破坏形态相近。(3)岩石试件在高应力作用下进入塑性流动状态,内部颗粒重新排列,内部小孔隙与大孔隙的占比减少,而中孔隙的占比显著增多,试件内部孔隙率整体降低。

To investigate the disturbance and failure mechanisms within high-stress surrounding rocks, this study conducted triaxial conventional compression and cyclic disturbance tests on rock-like specimens under various confining pressures, elucidating the specimens' disturbance stress-strain behavior and deformation failure charac-teristics. Additionally, Nuclear Magnetic Resonance (NMR) imaging tests were performed to delve deeper into these mechanisms from a microscopic standpoint. The findings reveal: (1) Under varying confining pressures, each specimen exhibited a threshold strength, beyond which axial deformation became markedly sensitive to dis-turbances, leading to significant specimen deformation upon reapplication of disturbances. Below this threshold, deformation showed insensitivity to disturbances. The ratio of threshold to ultimate strength reflects the speci-men's resistance to disturbances, which decreases with increasing confining pressure, indicating heightened sensi-tivity to disturbances under high-pressure conditions. (2) A weakening effect was observed in rock-like specimens under disturbance; for instance, specimens exhibited barrel failure under a conventional triaxial confining pressure of 10 MPa, while displaying oblique brittle failure akin to that observed under 5 MPa after disturbance, highlight-ing the transformative impact of disturbances on failure modes. (3) High-stress conditions prompted rock speci-mens to enter a plastic flow state, characterized by internal particle rearrangement and a significant shift in pore size distribution, with a notable decrease in both small and large pores in favor of medium-sized pores, overall reducing the specimen's porosity. These insights advance our understanding of the behavior of high-stress sur-rounding rocks under disturbances, offering valuable perspectives for engineering and geological applications.

国家自然科学基金资助项目(52274121);山东省自然科学基金资助项目(ZR2022ME162);济南市“新高校20条”资助项目(202228106)

王军,朱传根,李勋,等.类岩石试件三轴扰动破坏特性试验研究[J].采矿与岩层控制工程学报,2024,6(2):023034.

WANG Jun, ZHU Chuangen, LI Xun, et al. Experimental study on triaxial disturbance and failure characteristics of rock-like speci-mens[J]. Journal of Mining and Strata Control Engineering, 2024, 6(2): 023034.