Study on Permeability and Triaxial Experiments of Clay under Dry-Wet Cycles and Compaction

Abstract

The permeability and mechanical properties of clay are significantly influenced by the seasonal wet-dry cycles and compaction. In this study, laboratory experiments were conducted to investigate the effects of the number of wet-dry cycles and compaction degree on clay behavior. The results indicated that the initial compaction degree had a significant influence on the permeability characteristics of soil specimens subjected to wet-dry cycles. Specifically, the permeability coefficients significantly decreased with increasing compaction degree. The measured permeability coefficients for low, medium, and high-compacted samples were 5.48×10^-8 m/s, 8.33×10^-9 m/s, and 7.29×10^-10 m/s, respectively. After three wet-dry cycles, the permeability coefficients of the low and medium-compacted samples decreased to 1.16×10^-8 m/s and 9.08×10^-9 m/s, whereas that of the high-compacted sample increased to 6.76×10^-9 m/s. A relatively strong linear relationship was observed between the permeability coefficient and the compaction degree on a semi-logarithmic plot. Both cohesion and internal friction angle increased with increasing compaction degree. With a growing number of wet-dry cycles, the failure mode of the specimens gradually transitioned from strain-hardening to strain-softening behavior. The modified Duncan-Chang model showed a relatively good fit for the stress-strain relationship of the sample. This research offers theoretical references and technical support for practical applications in clay-related engineering fields.