Influence of groundwater on micro-cracking behaviour and failure mechanism of deep hard rock

• Published in: Measurement : journal of the International Measurement Confederation 2024-09, Vol.237, p.115175, Article 115175
• Main Authors: Lv, Xudong, Zhang, Ru, Zhang, Anlin, Ren, Li, Zhang, Zetian, Xie, Jing
• Format: Article
• Language: English
• Subjects: Acoustic emission; Deep tunnel; Failure mechanism; Hard granite; Micro-cracking evolution; Water softening
• ISSN: 0263-2241
• DOI: 10.1016/j.measurement.2024.115175

•The mechanical deterioration of granite under the effect of groundwater was revealed.•An optimized method for extracting the dominant frequency of rock AE was proposed.•The microcracking behavior and failure mechanism of saturated granite were evaluated. To address the water-inrush hazards encountered in deep tunnels in the rugged terrain of Southwest China, the uniaxial compression tests and acoustic emission (AE) monitoring were conducted on granite samples taken from a deep tunnel with different durations of saturation (2 days and 30 days), and the results were compared with those of natural granite samples. The results revealed the influence of groundwater on the mechanical properties, micro-cracking behavior, and failure modes of granite, which provided guidance for the deep tunnel construction. Based on the previous work, an optimized method for extracting the dominant frequency of rock AE signals considering the effect of groundwater on hard granite was proposed, which corrected the inaccurate extraction problem in the traditional method. The optimally extracted high dominant frequency AE signals could also be used as a precursor of rock failure.