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

Abstract

Glacier collapses can occur due to shear failure at the ice-rich debris-rock interface (IDRI). In order 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, -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 decrease by 62.5% to 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.