Advance and review on freezing-thawing damage of fractured rock

The structure and strength of fractured rock mass are different from those of soil, so the existing theory for frozen soil is not applicable to the problems of crack initiation, propagation and network development in rock mass under low temperature. The moisture migration and the pressure due to frost heaving in freezing-thawing process and the crack propagation after freezing-thawing process have been the key issues. The research on the mechanism of moisture migration should be based on the micro-scale and more attentions should be focused on the flow characteristics of unfrozen water film considering ice segregation. The damage degree of fractured rock under freezing-thawing is directly affected by the frost heaving pressure. However, the frost heaving pressure and crack extension are affected by many factors, such as the crack shape and the spatial position, the unfrozen-water content, the freezing temperature and the rock properties. During the last several decades, the efforts have been focused on the investigation of the extension of frost cracks with theoretical analysis, laboratory tests and field monitoring. Although remarkable achievements have been obtained, research on freezing fractured rock at present is far from mature. In order to reveal the mechanism of damage development of fractured rock mass under freezing-thawing, future studies should be based on the investigation of water migration in fractured rock mass with laboratory tests and the establishment of calculation method of frost heaving pressure. Then, the influence of frost heaving pressure on the development of fracture network can be studied combined with the criterion of crack extension. ©, 2015, Academia Sinica. All right reserved.