Reducing frictional constraint in compression testing through lubrication

The squeezing scenario in deep weak rock tunnels can hinder underground construction. However, due to the limitations of test technologies at hand, the real excavation stress path cannot be mimicked in the laboratory. Thus, the large deformation mechanism of deep weak rocks still remains unclear. For this, a true triaxial apparatus (TTA) to investigate the mechanical responses of deep weak rock under excavation stress paths in field and reveal...