Objective Under the influence of global warming and a humidifying climate, the frequency of the rock−ice avalanche disaster is steadily increasing. Among these, the occurrence of ice−rock avalanches is primarily controlled by ice−rock mixtures at the contact zones between glaciers and bedrock. However, the weakening characteristics of ice−rock mixtures and the formation processes of the ice−rock avalanche−debris flow disaster chain remain unclear.

Methods This study focuses on the Chaqu Basin of the Qinghai−Xizang Plateau. Temperature−controlled triaxial experiments were conducted to investigate the failure characteristics of ice−rock mixtures under conditions of −8~0°C, ice−rock ratios of 0.25~0.75, and confining pressures of 200~400 kPa. Additionally, the motion patterns of the Chaqu BC01 high−altitude ice−rock avalanche hazard under −4°C conditions were analyzed using Massflow simulations.

Results The results indicate that the peak shear strength, internal friction angle, and cohesion of ice−rock mixtures decrease with increasing temperature. As temperature rises, the strength variation of ice−rock mixtures transitions from strain softening and shear failure to strain hardening and dilatancy failure. With an increasing ice−rock ratio, the stress−strain characteristics of the mixtures shift from strain softening to strain hardening. Using the Mohr−Coulomb strength criterion and Boltzmann function, the relationships among strength, ice−rock ratio, and temperature were characterized, and a strength failure criterion incorporating temperature and ice−rock ratio parameters was established.

Conclusions Under extreme weather conditions, the Chaqu ice−rock avalanche is prone to forming an ice−rock avalanche−debris flow−river blockage disaster chain, which could obstruct the Palongzangbu River, posing significant threats to residents and infrastructure in the Palongzangbu River Basin.