Abstract: In this study, conventional triaxial tests were conducted to systematically investigate the strength characteristics of loess under the conditions of drying-wetting cycles. We proposed the methods for calculating structural strength and decay intensity of loess, and then discussed the effects of confining pressure and water content on structural strength and decay intensity. The relationship between structural strength and decay intensity was studied as well. The results show that the structural strength and decay intensity decrease with increasing water content and reveal a good logarithmic function with water content. The structural strength and decay intensity increase with the increase of confining pressure, which had a good linear function. The attenuated strength value of undisturbed loess after several drying-wetting cycles is almost equal to the sum of attenuated strength value of remolded loess and structural strength. It is proved that the action of the wetting-drying cycle not only broke the original structure of undisturbed loess, but also made the undisturbed and remolded loess have the same structure of soil mass.

Key words: wetting-drying cycle, loess, conventional triaxial test, structural strength, decay strength