Constitutive Behavior of Silt Under Dry–Wet Cycles and Nonlinear Strength Effects

The article explores the critical issue of preserving earthen sites, which are ancient ruins constructed primarily with soil and hold immense historical, cultural, and scientific value. These sites, particularly in regions like Henan province, are often constructed with silt and are highly susceptible to deterioration due to natural environmental factors such as rainfall, groundwater fluctuations, and high-temperature evaporation. The study investigates the impact of dry-wet cycles on the mechanical properties of silt, revealing how these cycles can lead to significant deterioration, including cracks, undercutting, and collapse. The research highlights the variability in soil mechanical properties due to differences in physical properties, sample preparation, stress conditions, and the process of dry-wet cycles. It presents a comprehensive analysis of the stress-strain relationship curves of silt under different dry-wet cycles and confining pressures, demonstrating how the soil's strength and cohesion vary over time. The article introduces an improved soil column test apparatus that simulates the natural environment of earthen sites, allowing for a non-uniform water content distribution. This innovative approach enables a more accurate assessment of soil mechanical properties and the development of a nonlinear strength criterion. The study also proposes a Duncan-Chang model that considers the number of dry-wet cycles and nonlinear strength, providing a more reliable tool for predicting soil behavior and enhancing the preservation of earthen sites. The findings underscore the importance of tailoring test designs to regional soil characteristics and environmental conditions, offering valuable insights for the conservation of cultural heritage sites worldwide.