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Theoretical analysis and experimental verifications of frost damage mechanism of sandstone |
JIA Hailiang1,XIANG Wei1,TAN Long1,ZHANG Weili1,ZENG Wen2,CAO Shen1,CHENG Chaojie1 |
(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) |
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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.
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陈卫忠,谭贤君,于洪丹,等. 低温及冻融环境下岩体热,水,力特性研究进展与思考[J]. 岩石力学与工程学报,2011,30(7):1 318- 1 336.(CHEN Weizhong,TAN Xianjun,YU Hongdan,et al. Advance and review on thermo-hydro-mechanical characteristics of rock mass under condition of low temperature and freeze-thaw cycles[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(7):1 318- 1 336.(in Chinese))
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