A prediction model for uniaxial compressive strength of deteriorated rocks due to freeze-thaw

摘要

The structure deterioration of rock under freeze-thaw is an important research subject for natural building niaterials and engineering construction in cold regions exposed to severe climatic conditions. The loss of long-term uniaxial compressive strength after freeze-thaw is a crucial index for frost resistance which needs to be estimated by damage model. In the previous studies, some prediction models were proposed with regression analysis of laboratory data from massive rock samples while the mechanism of freezing-thawing damage was ignored. In order to derive much more accurate and economic results, in this study, a new prediction model of uniaxial compressive strength against freeze-thaw action was proposed based on elastic-plastic theory and fatigue damage mechanics considering the actual state of stress distributing in rock under freeze-thaw. The unknown material parameters in the present model could be determined by testing P-wave velocity instead of testing uniaxial compressive strength. This model was validated by three previous experiments including freeze-thaw test of low porosity saturated sandstones, high porosity saturated ignimbrites and unsaturated welded tuffs. The results indicate that these model equations are more reliable for all the chosen rocks with different porosity and water saturation compared with the decay function model proposed by Yavuz et al. (2006), besides it can be more convenient and useful to predetermine uniaxial compression strength of rock under any freeze-thaw cycle. (C) 2015 Elsevier B.V. All rights reserved.