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<p>Frictional stick–slip behavior along faults is a key mechanism that causes severe damage in fault-crossing tunnels, necessitating a fundamental understanding of its sliding mechanics for fracture-resistant design. As fault-zone rock properties critically govern frictional behavior in laboratory simulations, this study examines gneiss through integrated petrographic and XRD analyses to characterize its mineral composition and tectonic evolution. To quantify the effects of schistosity orientation (0°/90°) and water saturation (dry/saturated) on mechanical properties, we conducted systematic uniaxial compression tests; mechanical responses were characterized through stress–strain behavior, acoustic emission monitoring, and failure mode analysis, with a focus on the failure mechanism of dry specimens with 0° schistosity. Experimental results demonstrate that: Saturated specimens exhibit ~ 35% strength reduction due to mica hydration, inducing unstable fracture propagation; Dry 0°-schistosity specimens maintain higher strength with localized failure modes, demonstrating mechanical stability ideal for friction experiments; These specimens display a unique “plastic–elastic–plastic” deformation sequence, featuring precursor stress drops (2–3%) before catastrophic failures (8–26%), indicative of progressive rupture kinematics. Correlating with prior stick–slip tests, we hypothesize that such staged ruptures may simulate foreshock-main slip sequences in natural faults. The findings suggest the potential of dry gneiss to replicate fault slip nucleation processes, offering material-specific insights for laboratory studies of fault mechanics and precursory signals.</p>

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Fracture Properties of Gneiss at Active Faults and their Effect on Stick–Slip Sliding Tests

  • 期刊论文

  • 发表日期：

    2025年8月21日

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  • Haixiang Zhang,
  • Lianjin Tao,
  • Xu Zhao,
  • Yanyan Li,
  • Cheng Shi,
  • Hehua Zhu

摘要

Frictional stick–slip behavior along faults is a key mechanism that causes severe damage in fault-crossing tunnels, necessitating a fundamental understanding of its sliding mechanics for fracture-resistant design. As fault-zone rock properties critically govern frictional behavior in laboratory simulations, this study examines gneiss through integrated petrographic and XRD analyses to characterize its mineral composition and tectonic evolution. To quantify the effects of schistosity orientation (0°/90°) and water saturation (dry/saturated) on mechanical properties, we conducted systematic uniaxial compression tests; mechanical responses were characterized through stress–strain behavior, acoustic emission monitoring, and failure mode analysis, with a focus on the failure mechanism of dry specimens with 0° schistosity. Experimental results demonstrate that: Saturated specimens exhibit ~ 35% strength reduction due to mica hydration, inducing unstable fracture propagation; Dry 0°-schistosity specimens maintain higher strength with localized failure modes, demonstrating mechanical stability ideal for friction experiments; These specimens display a unique “plastic–elastic–plastic” deformation sequence, featuring precursor stress drops (2–3%) before catastrophic failures (8–26%), indicative of progressive rupture kinematics. Correlating with prior stick–slip tests, we hypothesize that such staged ruptures may simulate foreshock-main slip sequences in natural faults. The findings suggest the potential of dry gneiss to replicate fault slip nucleation processes, offering material-specific insights for laboratory studies of fault mechanics and precursory signals.