Abstract:

Through adjusting the working parameters of temperature and humidity in the constant temperature and humidity equipments and changing the expansive soil evaporation path, the non-uniform shrinkage test of saturated expansive soil under different drying rates is achieved, which combined with swelling test and direct shear test to research the expansion and contraction characteristics and strength properties of expansive soil under non-uniform shrinkage test. The experimental results indicate that the smaller the drying rates is, the larger the deformation of the expansive soil and the higher of the shear strength is. The contraction, shrinkage deformation and shear strength of the expansive soil under uniform shrinkage condition are larger than non-uniform shrinkage condition. The main reason for these differences is the different paths of evaporation in non-uniform shrinkage test, which leads to different water contents along the depth direction, different matrix suction and different strain. The non-uniform shrinkage changes the homogeneity of expansive soil and limits the expansion and contraction characteristics and strength properties of expansive soil.

Key words: expansive soil, drying rate, non-uniform shrinkage, expansion, strength