Real-time computerized tomography (CT) experiments on sandstone damage evolution during triaxial compression with chemical corrosion

摘要

The computerized tomography (CT) images and CT values for the process of compression micro-cracking, and dilation up to the failure of sandstone specimens under different loading levels have been obtained using the real-time CT technique for triaxial loading of sandstone subjected to chemical corrosion. Clear CT images and CT value of the stages from compression of micro-cavities -> emergence of micro-cracks -> bifurcation -> development -> fracture -> collapse -> unloading can be observed. The CT value, equivalent to rock density at the CT scan layer, is the most important parameter describing the damage evolution process of rock. The paper also presents results of the corrosive influence of chemical solutions with different pH values and ionic concentrations on the sandstone strength. Stronger acidity (pH <7) or causticity (pH > 7) has a stronger effect on the rock micro-fracturing evolution. The mechanism of damage evolution of sandstone is analyzed and a damage model based on the chemical corrosive influence and CT values is proposed.