Study on the Microstructure Evolution and Strength Damage Mechanism of Dolomite under Dissolution Condition

Dolomite is a common type of natural soluble rock. The strength rock decreases under the action corrosion, which has significant impact on self-stability and long-term safety tunnel surrounding To reveal microscopic structure evolution strength-damage law carbonate caused by chemical series tests such as corrosion test, uniaxial compression test electron microscope scanning are conducted at different pH values dolomite Doushantuo Formation. dissolution exhibits four typical stages: initial stage, secondary acceleration stable rate stage attenuation stage. During process, 25.91 times that maximum 76.2% after 21 days dissolution. For macroscopic failure, developed from 1 to 2 external fractures multiple internal penetrated, specimen transforms brittle flexible. microstructure, sample characteristics along joint surface, intensified edge, etc. porosity increase 0.6%/d; however, length–width ratio pores maintained 1.7–1.85, indicating development in directions similar. results this study have enriched mechanism and, addition, important reference value for stability evaluation karst environments.