Abstract Geological discontinuities govern the strength and deformation of rock mass and play an important role in the stability of geotechnical excavations, such as tunnels, caverns, slopes, and mines. In this paper, the failure mechanism of a tunnel in the vicinity of a fault zone is investigated by physical model tests with dimensions of 3 m × 2.4 m × 0.4 m, in which the non-contact Digital Image Correlation (DIC) technique is employed to provide full-field displacement measurements. Results show that the fault zone near the tunnel shoulder has a significant influence on the stability of the surrounding rock, in terms of strain localization and failure initiation. With the increase of surcharge loading, cracks initiate at the two sidewalls, following by the initiation of cracks at the left shoulder and the crown. Cracks propagate to the fault zone eventually, leading to asymmetrical collapse. The stress loosening zone (SLZ) in the surrounding rock after tunnel excavation is significantly influenced by the fault zone near the left shoulder of the tunnel, showing the occurrence of stress redistribution. It is recommended to implement reinforcement in the rock mass between the tunnel and the fault to improve the stability.

中文翻译：

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基于非接触DIC技术的断层带岩石隧道渐进破坏行为试验分析

摘要 地质不连续性控制着岩体的强度和变形，对隧道、洞室、边坡、矿山等岩土开挖的稳定性起着重要作用。本文通过尺寸为3 m × 2.4 m × 0.4 m的物理模型试验研究了断层带附近隧道的破坏机制，其中采用了非接触式数字图像相关（DIC）技术提供全场位移测量。结果表明，隧道肩部附近的断层带对围岩的稳定性，在应变局部化和破坏开始方面有显着影响。随着超载载荷的增加，裂缝在两个侧壁开始，随后在左肩和冠部开始裂缝。裂缝最终传播到断层带，导致不对称坍塌。隧道开挖后围岩中的应力松散带（SLZ）受隧道左肩附近断层带的影响显着，表现为应力重新分布的发生。建议对隧道与断层之间的岩体进行加固，以提高稳定性。