The long-runout mechanism of ice–rock avalanches is strongly influenced by frictional heating and ice–water phase transition and the experimental evidence of these processes remain limited. In this study, an improved ring shear apparatus with temperature measurement was developed to investigate the friction behavior and temperature evolution under ice-free and ice-containing conditions. The results show that temperature increase was approximately linear under saturated drained conditions, with the temperature change rate positively correlated with normal stress and shear rate. Under saturated undrained conditions, shear liquefaction reduced frictional resistance and weakened temperature increase. For frozen soils with 30% ice content, ice mainly influenced the initial stage of shear failure, accompanied by a shear dilation effect. The total friction angle first increased to a peak value and then gradually stabilized at a residual state (30°), with a temperature increase of 6°C. These findings provide new experimental insights into the thermal effects and mobility mechanisms of ice–rock avalanches.

ice–rock avalanches,mobility mechanisms,thermal effects,ring-shear experiments