Damage Characteristics of Altered and Unaltered Diabases Subjected to Extremely Cold Freeze-Thaw Cycles

Altered and unaltered diabases are commonly deposited on hydrothermally mineralized slopes. To study their damage characteristics during freeze-thaw cycles, they were sampled from Cihai iron ore mine located in an extremely cold region, Xinjiang, China and examined using acoustic and X-ray diffraction experiments to analyze the differences in their main mineral components and explore their damage characteristics under freeze-thaw conditions. Based on the results of these experiments, their damage and degradation patterns were obtained and the evolution of their physical characteristics including the rock mass loss rate (L (F)), rock strength loss rate (R (sigma) ), P-wave velocity loss rate (V (l)), and freeze-thaw coefficient (K (f)) was analyzed. In addition, two groups of equations were established to characterize the relationships of these physical and mechanical properties of the rock specimens with the number and temperature of freeze-thaw cycles. The results show that the mineral composition of diabase changes during its alteration, showing increased clay and calcite, and the degradation and evolution patterns of the physical and mechanical parameters (L (F), R (sigma) , V (l), and K (f)) of the altered rocks during freeze-thaw cycles are different from those of diabase, with the altered diabase exhibiting greater damage than the diabase.