(1. Faculty of Engineering，China University of Geosciences，Wuhan，Hubei 430074，China；2. Three Gorges Research Center for Geo-hazard，Ministry of Education，China University of Geosciences，Wuhan，Hubei 430074，China)
Abstract：Due to the complexity of rock properties and the variability of environmental conditions，frost damage of rock can hardly be attributed to one single mechanism. Nonetheless，in most of the cases，one or more mechanisms dominate the process. We firstly reviewed the existing theories on frost damage and compare their applicable conditions. Afterwards the controlling role of the pore structure of sandstone(as an example of porous rock) in the frost damage process was discussed，and the “representative element of frost damage” was defined. The probable damage mechanisms and the predominant mechanism of sandstone under different freezing patterns were identified according to the thermodynamics. Under the low freezing rate，the capillary and crystallization pressure were found to play a key role in damaging sandstone，while the volumetric expansion process was restrained. While under the high freezing rate，the volumetric expansion process and hydraulic pressure process contributed predominately to the damage of sandstone rather than the capillary and crystallization pressure. To test the above findings，a series of experiments on frost damage of sandstone were conducted，including the direct observation of the microstructure of sandstone under environmental scanning electron microscope(ESEM) and monitoring of the frost deformation of sandstone using strain gages. The experimental results are consistent with the theoretical analysis.
MCGREEVY J P，WHALLEYW B. Rock moisture content and frost weathering under natural and experimental conditions：a comparative discussion[J]. Arctic and Alpine Research，1985，17(3)：337-346.
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