FRACTAL RESEARCH THE CRACK CHARACTERISTIC EXPANSIVE SOIL UNDER WETTING-DRYING CYCLE

By means of the wetting-drying cycle tests of triaxial and direct-shear on the expansive soil.The test finds that with first wetting-drying cycle triaxial test,the crack ratio in expansive soil sample surface is the largest increase,with second to fourth wetting-drying cycle,the crack ratio in expansive soil sample surface is the bigger increase.And the crack ratio in expansive soil sample surface is the little increase,with the wetting-drying cycle is more than five.And the same result is finds in the direct-shear test.All in all,With the number of times wetting-drying cycle increasingly,the crack ratio in expansive soil sample surface is constantly increasing.