A series of CT-triaxial tests of an intact unsaturated Q3 loess and remolded loess were conducted using a stress controlled CT multi-function triaxial apparatus developed, and the changes of the internal structure was measured using CT technology, The distinctive CT images and detailed CT data were obtained during nondestructive of the loess, which explains meso-structure evolution of loess under triaxial shear failure conditions from the microscopic view. The results show that, With the increase of confining pressure, the curves of relationship between meridional stress and axial strain transformed into hardening from weak softening gradually, The curves of relationship of shear failure strain softening between body strain and axial strain transformed into contraction form from dilatation. The curves of relationship between CT number and average axial strain experience a slight increase first, then reduce gradually. The relation curves between average CT number and the axial strain of shear failure strain hardening type increase rapidly in the initial stage, and then slow growth in the shearing process. The failure process of remolded loess shear specimen in central shear damage smaller, crack mainly derived in the periphery of the samples. The performance of intact loess cementation zone gradually broken, empty area showed due to the slip granular soil around and gradually by compression. CT technology makes the soil meso-structure research to a quantitative stage, and provides the experimental basis for establishing the constitutive model of soil structure and structural evolution equations. © 2016, China Water Power Press. All right reserved.
