An experimental study on the influence of ice saturation and sub-zero temperatures on the dynamic mechanical properties of sandstones

Abstract

The influence of ice saturations on the mechanical properties of rocks in cold regions is of great significance for many engineering projects. This study adopted a nuclear magnetic resonance (NMR) technology to measure the different ice saturations of sandstone specimens accurately. The split Hopkinson pressure bar (SHPB) was espoused to conduct dynamic compressive tests on sandstone with different ice saturations at room (26 ͦ C) and various low temperatures of 0 ͦ C, −5 ͦ C, −10 ͦ C, −20 ͦ C, −30 ͦ C and − 40 ͦ C. The findings revealed an increase in the dynamic mechanical strength's parameters, including dynamic elastic modulus (Ed) and dynamic compressive strength of sandstone with decreasing temperatures from 0 °C to −20 °C. The dynamic mechanical strength of sandstone reaches its peak value when the temperature drops from −20 ͦ C to −30 ͦ C, and a reduction in dynamic strength is evidenced when the temperature declines from −30 ͦ C. The results indicated that the dynamic mechanical strength of dry and fully saturated sandstone initially increased and then decreased when the temperature reached −40 °C, showing a clear negative trend. A reduction in temperature increases the dynamic mechanical strength of unsaturated sandstone, and the lower saturation leads to a more pronounced enhancement effect. Furthermore, the Ed and strength damage factors elucidate that varying ice saturations greatly affect the strength of sandstones with different porosities.