Abstract: In an attempt to reveal the meso-evolution of shear band of soil in loading process, triaxial test was performed on an undisturbed loess specimen obtained from Shaanxi, China, and real-time CT scanning was conducted to obtain specimen slices at different strain conditions. The process of local cracks developing into global shear band was reproduced under triaxial loading conditions. The relationship between CT value and soil density was deduced. End restraint phenomenon was observed under isotropic consolidation condition, and the variation in CT mean value against axial strain was analyzed. The further development of cracks was mainly in post-failure stage, and reached stable at residual strength state. Along a typical horizontal section, the local CT value and density show normal distribution, which reflects the reduction of peak value and the widening of waveform with the rising of axial strain.

Key words: loess, triaxial test, CT scanning, shear band, crack, meso-evolution