Methodology for Establishing Comprehensive Stress Paths in Rocks During Hollow Cylinder Testing

We here systematically investigated the methodology for establishing comprehensive stress paths with the aim of developing hollow cylinder apparatuses for rock mechanics. The research was based on the stress combination in element of hollow cylinder sample with varied loading analysis treatment. For this purpose, we discussed the mechanism underlying the variations in principal stress magnitude and principal stress rotation. The orientation angle of the major principal stress was defined in an alternative prospect. Then a series of stress paths was introduced, including the hydrostatic pressure stress path, principal stress magnitude variation stress path on the deviatoric plane, pure principal stress rotation stress path, and the complex stress path coupling the variation in the magnitude of principal stress and principal stress rotation effect. The comprehensive stress paths were analyzed with rock mechanical theory and a mathematical approach. The suggested loading methods were examined using simulation loading tests, laboratory case tests and special case verification. The results showed successful completion of different stress paths. The proposed methodology was first investigated systematically in rock mechanics, contributing to development of the new hollow cylinder apparatus and complex rock engineering simulation.