Triaxial CT Tests of Meso-Structure Evolution of Remodeled Cohesive Soil in Hefei

In order to investigate the meso-structure characteristic of unsaturated cohesive soil, unsaturated consolidated-drained triaxial shear tests for remodeled cohesive soil in Heifei were carried out under different suctions and net confining pressures with CT (computed tomography) multi-function triaxial apparatus, and the CT images and corresponding CT data (CT data average and variance) of its inner structure evolution were obtained. The research result shows that net confining pressure has a great effect on the meso-structure evolution of soil. When the net confining pressure is low, original holes in soil disappear, unsaturated cohesive soil will generate cracks rapidly after transient compaction, and the width and length of cracks extend with time. The larger the suction is, the more significant the crack propagation is. The CT data average decreases by 0.26% to 4.16% compared with the original value, while the CT data variance increases by 15.82% to 37.80% compared with the original variance to indicate that soil density becomes nonuniform. When the net confining pressure is high, soil as a whole is compacted and almost does not generate cracks. Compared with the original values, the CT data average increases by 1.22% to 14.87%, and the variance decreases by 10.02% to 83.37% to indicate that soil density becomes uniform and the soil body is more compact.