Benchmark experiment on shear behavior of ice-filled planar rock joints using a novel direct shear testing apparatus

• Published in: International journal of rock mechanics and mining sciences (Oxford, England : 1997) Vol. 178; p. 105757
• Main Authors: Li, Bo, Gong, Xin, Wang, Gang, Qiao, Jiaxing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2024
• Subjects: Aperture; Debonding; Ice-filled joint; Ice-layer thickness; Shear behaviour; Debonding; Ice-filled joint; Aperture; Ice-layer thickness; Shear behaviour
• ISSN: 1365-1609
• DOI: 10.1016/j.ijrmms.2024.105757

Geo-hazards associated with rock slope failures in alpine regions have become increasingly prominent subject to the climate change. Shear behavior of ice-filled rock joints plays an important role in the stability of jointed rock slopes. To explore the shear behavior and failure mechanism of frozen rock joints, granite and sandstone specimens containing a planar joint were prepared. Direct shear tests were conducted on joints with different ice-layer thicknesses based on a novel apparatus designed for testing coupled processes of rock joints. Results show that the aperture of joints (ice-layer thickness) exerts significant influences on the shear strength of ice-filled joints. The cohesive strength of ice-filled joints evolves exponentially with the varying ice-layer thickness and reaches maximum values when the thickness becomes 2–3 mm. Due to the different surface textural properties, the cohesion of the granite joint is more significantly affected by the ice-layer thickness than that of the sandstone joint. The friction angle exhibits a monotonic descending trend and stabilizes when the thickness reaches 4.0 mm. The failure mode of joints with different ice-layer thickness can be categorized into four types: wear and slip of the ice film, fragmentation of the ice layer, debonding of the ice-rock interface, and mixed failure, according to the ice-layer failure characteristics and the strength behavior. The established regression functions taking into account the ice-layer thickness and temperature could serve as basis for mechanical parameter estimation of ice-filled joints.