Micro-dissolution mechanism and macro-mechanical behavior of red-bed soft rock under dry-wet cycle

Abstract

The microscopic pore characteristics of rocks have an important influence on their macroscopic mechanical behavior. The micro-pore dissolution mechanism of red-bed soft rock was revealed by the dry-wet cycle method, and its macroscopic mechanical behavior was studied by a series of uniaxial compression tests. The results show that with an increase in the number of dry-wet cycles, the micro-pore dissolution and micro-grain spalling of red-bed soft rock result in its porosity increasing nonlinearly. Under the action of the axial load, the number of micro-fractures increases and evolves from tensile fracture to shear fracture, and the macroscopic failure mode changes from brittle splitting failure to ductile conical failure.