Experimental study on the shear mechanical behavior of ice-rich debris–rock interface: effects of temperature, stress and ice content

Glacier collapses can occur due to shear failure at the ice-rich debris–rock interface (IDRI). To examine the shear behavior of IDRI, shear tests were conducted on artificial IDRI specimens with varying ice contents (40%, 65%, and 90%), normal stresses (150, 250, 350, 450, and 550 kPa), and temperatures (−1, −3, −5, −7, and −9 °C). Our findings reveal that temperature has the most significant impact on both peak and residual shear strength, followed by normal stress and ice content. As the temperature increases from −9 to −1 °C, the peak and residual shear stress decreased by 62.5%–78%. Notably, for IDRI with the lowest ice content (40%), the residual shear stress is highly influenced by normal stress. We have developed an improved Mohr–Coulomb strength criterion of IDRI in which the cohesion and internal friction angle are determined by ice content and temperature. Furthermore, we propose a novel constitutive model, based on the disturbed state concept, to describe the shear behavior of IDRI. This model combines a spring model and a hyperbolic model. We also discuss the mechanisms through which ice content and temperature influence the shear deformation modes and shear strength of IDRI.