Dynamic modeling of the moisture and salt's transport in the unearthed terracotta warriors of emperor Qin's mausoleum museum, China

Abstract

Terracotta figurines excavated from archaeological sites frequently exhibit salt damage due to moisture-salt transport. Understanding this dynamic within the terracotta figurines and soil system is essential for accurately predicting salt damage and implementing well-informed, timely preventative measures. While moisture-salt transport in the soils of historical sites is well-documented, the numerical modeling of this process is rare, specifically within the Terracotta figurines-soil coupled system. In the present work, a numerical model focused on the Terracotta figurine-soil system at Emperor Qin's Mausoleum Museum (China) was established, which employed the variable saturation Richards flow equation and the Fickian advection-diffusion equation. The model was validated using soil column experiments. The results showed that the semi-buried figurines were more susceptible to salt damage, with uneven salt distribution primarily due to moisture-salt transport at the interface. After the excavation, the first month was identified as a critical period for rapid migration of moisture and salt, representing the highest risk of damage. These insights offer a framework for estimating the risk of salt damage over time, underpinning the development of future abatement strategies. This study not only advances the understanding of salt damage in Terracotta figurines but also lays the groundwork for safeguarding these archaeological treasures.