Heterogeneous strain and bonded granular structure change in triaxial specimen studied by computer, tomography

In recent years, the method of x-ray computer tomography imaging has been used to characterize the microstructure of asphalt concrete, cement concrete, soil, and rock. This paper focuses on developing an algorithm that links the particle identity at different load steps and thus provides sequential movements of particles. The measured data from a specimen under triaxial load is analyzed to study the nonuniform strain field and to identify shear band formation. Packing structure change and the evolution of fabric tensors due to external load are discussed. The validity of a commonly used kinematic hypothesis in granular mechanics is also evaluated.