An Experimental Study on Characteristics of Impact Compression of Freeze-Thawed Granite Samples Under Four Different States Considering Moisture Content and Temperature Difference

Abstract

The mechanics of rock masses in cold regions have attracted the attention of researchers from all over the world, and the concern here is that the mechanical properties of rock masses are inevitably weakened under freeze-thaw cycles. In this paper, firstly, granite samples were subjected to different freeze-thaw cycles, after that, we dealt with the freeze-thawed samples considering four different states, such as saturated and frozen states, saturated and normal temperature states, dry and frozen states as well as dry and normal temperature states. The impact compression test was carried out by using the Split Hopkinson Pressure Bar (SHPB) device. Results show that the impact strength of granite samples deteriorates with the increase of freeze-thaw cycles in the same state, for samples in different states, although the number of freeze-thaw cycles is equal, the degree of deterioration of the impact strength is different. For freeze-thawed granite samples in the same state, the dynamic elastic modulus decreases with the increase of freeze-thaw cycles, and its degree of decrease is different for different states. Under the same freeze-thaw cycles, the deterioration of mechanical properties of granite samples is different in four different weather states, for example, the dynamic elastic modulus from large to small is generally as follows: saturated and frozen states, saturated and normal temperature states, dry and frozen states as well as dry and normal temperature states. Finally, the freeze-thaw influence factor is proposed to describe the damage of granite samples. All in all, it can be concluded that water and low temperature strengthen the influence of freeze-thaw cycles on the dynamic mechanical properties of granite samples.