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Shallow failures often occur in earthen sites. The nonlinear strength criteria of silt and their correlation with dry-wet cycles are necessary for evaluation of failure problems of earthen site exposed to natural environments, such as rainfall and evaporation. Thus, in this study, a designed soil column and method in line with the natural environment characteristics of earthen sites were adopted to study the effects of the number of dry-wet cycles on the shear mechanical properties of the site silt under consolidated undrained triaxial conditions. The results show that the strength of silt and its parameter, cohesion c, do not monotonically decrease with the number of dry-wet cycles but exhibit a trend of initially increasing and then decreasing. The nonlinear characteristics of the strength of silt are remarkable, particularly in the range of small normal stresses. Based on Baker's generalized power law strength criterion, a nonlinear strength criterion considering the number of dry-wet cycles of silt was established with the parameter A of the strength criterion initially increasing and gradually decreasing and the value of N essentially unchanged. The improved Duncan-Chang model considering the dry-wet cycle effect and strength nonlinearity of silt in earthen sites was presented and verified. The research can offer significant theoretical support for the analyses of shallow collapses and other issues related to failure problems of earthen sites.

来源平台：GEOTECHNICAL AND GEOLOGICAL ENGINEERING