Brittle fracture and plastic creep of the completely decomposed granite presented in CT

Abstract

Completely decomposed granite (CDG) with different structures shows different patterns in deformation and failure as brittle fracture or as plastic creep in triaxial test. It is necessary to monitor and to compare the fabric changes due to stress in real time during test. By means of the computerized tomography (CT) technique for monitoring deformation and failure of soils in real time without suspending the mechanical test and disturbing samples, a newly designed triaxial test machine was used to test CDG from Hong Kong in a procedure of saturation, consolidation and undrained condition. It was found that CT data (images and values) depicts the failure patterns as brittle fracture or as plastic creep at 3-D in real time. The results were concordant with stress–strain curves and observation of the appearance of samples before and after tests.