Mechanical behavior of marble exposed to freeze-thaw-fatigue loading

Freeze-thaw-fatigue (FTF) testing was carried out on Tibet marble at lab-scale by considering various Freeze-Thaw (FT) cycles and multi-level cyclic loading. The aim is to investigate the evolution of deformation and damage related parameters as well as the hysteresis behavior. The test results show that an increase of FT cycles and fatigue load level both accelerate the damage rate of marble. A rock suffering more FT cycles shows a much larger axial strain rate, radial strain rate and increasing Poisson's ratio. The relation of axial strain rate, radial strain rate and Poisson's ratio rate versus fatigue load level can be fitted by an exponential function. A warning level is defined according to the evolution of radial strain and Poisson's ratio which can inform before dilation starts. Moreover, the hysteresis behavior of stress-strain is investigated. It has been proven, that the proposed two indexes, advance ratio and lag ratio are effective precursors for rock failure prediction if subjected to FTF actions. The drastic drop of the advance ratio and the increase of the lag ratio are the indicators for forth-coming failure. The recommended warning limits for advance ratio and lag ratio for the tested marble are 5% and 70%, respectively.

Automated summary

The test results indicate that an increase in FT cycles and fatigue load level accelerates the damage rate of marble, leading to larger axial strain rate, radial strain rate, and increasing Poisson's ratio. A warning level is defined based on the evolution of radial strain and Poisson's ratio. Advance ratio and lag ratio are effective indicators for predicting rock failure when subjected to FTF actions.