Ice-rock avalanches have become increasingly frequent in warming high mountain regions. During motion, frictional and collisional heating induces ice melting, and the resulting meltwater can increase pore water pressure and reduce shear resistance. To investigate the coupled thermo-hydro-mechanical behavior of ice-rock avalanches, rotating drum experiments were conducted with different ice contents. Normal stress, pore water pressure, shear stress, and temperature were simultaneously monitored during sustained motion to characterize the coupled thermo-hydro-mechanical responses. Increasing ice content resulted in higher pore water pressure, lower shear stress, and a longer period of low temperature. Temperature evolution exhibited an initial cooling stage followed by warming, indicating the transition from ice melting to frictional heating. The coupled thermo-hydro-mechanical responses demonstrate gradual strength weakening caused by meltwater generation and pore water pressure buildup. Particle segregation developed during motion, with low density ice particles rising into the upper layer of the flow while denser gravel particles remained concentrated in the lower layer. These findings improve the understanding of thermo-hydro-mechanical coupling and particle segregation during ice-rock avalanche motion.

Ice-rock avalanche,THM coupling machanism,Rotating drum,Physical experiments