Comment on tc-2022-155

Abstract

Global warming causes many rockfall activities of the alpine mountains, especially when ice-filled joints in the rock mass become thawed. The warming and thawing of frozen soils and intact rocks was widely studied in the past several decades, however, the variation of shear strengths of ice-filled joints was not fully understood. Recently, some scholars studied the thawing process and strength loss of ice-filled joints at different temperatures, however, the influence of the joint roughness, opening and shear rate on ice-filled joints was not systematically investigated. In this study, a series of compression-shear experiments were conducted to investigate the shear strength of ice-filled rock joints by considering the effects of joint roughness, opening and shear rates. The shear strength quickly reduces with increasing temperature, especially above -1 ℃. In addition, the shear strength decreases with increasing joint openings but it increases with increasing joint roughness. When the joint opening is large enough, the effect of joint roughness disappears and the shear strength of ice-filled joints is equal to that of solid ice. Increasing shear rate will decrease the shear strength of ice-filled joints because the joint ice displays the brittle failure phenomenon at a high shear rate. The Mohr-coulomb criterion also can be used to characterize the relationship between the shear strength and the normal stress of ice-filled joints. However, a general strength model by considering the joint opening, normal stress and joint roughness should be proposed by a further study. This research can provide a better understanding of the warming degradation mechanism of ice-filled joints by considering the above important influencing factors.