(1. School of Architecture and Civil Engineering,Xi?an University of Science and Technology,Xi?an,Shaanxi 710054,China;
2. Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074,China)
Abstract:The fatigue damage theory has been proven to be practical in estimating the damage of rock subjected to the repeated action of freezing and thawing. The application of the established frost fatigue model in the calculation of rock damage in the natural environments still faces several challenges,for instance,how to simplify the complicated natural freezing and thawing action,how to define the damage variable reasonably and how to calculate the frost damage of rock caused by the joint action of multiple mechanisms. In this paper,analysis is carried out corresponding to the above challenges. The results indicate that the diurnal and annual freeze-thaw cycle should be the research focus in the engineering activities,which could be classified into the low-cycle or high-cycle fatigue loads according to the saturation degree of rock and the flow rate of unfrozen water in rock respectively. The change of the porosity of rock reflects the underlying frost mechanism,and the damage variables are thus defined by the flaw area and residual strain. The damage generated by high-cycle loads is comparable to that generated by low-cycle loads according to the fatigue damage model. Moreover,the effect of the action sequence of low-cycle and high-cycle loads should be taken into account.
贾海梁1,2,项 伟2,申艳军1,杨更社1. 冻融循环作用下岩石疲劳损伤计算中关键问题的讨论[J]. 岩石力学与工程学报, 2017, 36(2): 335-346.
JIA Hailiang1,2,XIANG Wei2,SHEN Yanjun1,YANG Gengshe1. Discussion of the key issues within calculation of the fatigue damage of rocks subjected to freeze-thaw cycles. , 2017, 36(2): 335-346.
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))
[2]
KRAUTBLATTER M,FUNK D,GUENZEL F K. Why permafrost rocks become unstable:a rock-ice-mechanical model in time and space[J]. Earth Surface Processes and Landforms,2013,38(8):876-887.
[3]
PUDASAINI S P,KRAUTBLATTER M. A two-phase mechanical model for rock-ice avalanches[J]. Journal of Geophysical Research-Earth Surface,2014,119(10):2 272-2 290.
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