Correlation assessment between degradation ratios of UCS and non-destructive properties of rock under freezing-thawing cycles

Abstract

Bedrocks of engineering projects are commonly affected by freezing-thawing (F-T) process in mountainous areas. Consequently, determining the degradation rate of rocks due to F-T cycles in cold areas has a key role in project design and its safety level. In this research, influence of F-T process on some physico-mechanical characteristics of three main rocks of Angouran mine (limestone, amphibolite-schist, and mica-schist) was investigated. For this purpose, unconfined compressive strength (UCS), Schmidt hardness, dry density, water absorption and porosity were firstly determined at five different F-T cycle numbers between 0 and 75 cycles. Increasing of the F-T number led to decrease of UCS, Schmidt hardness and dry density, whereas water absorption and porosity parameters were increased. It is also proved that the UCS loss of rock samples due to the F-T process was related to the losses of other physic-mechanical properties. Therefore, the changes of UCS losses were determined at 0, 7, 15, 40, and 75F-T cycles to establish their relationships. According to the results, after 75 cycles, there is a good relationship between UCS degradation ratio with those of the water absorption and Schmidt hardness (R2 = 0.99).