Prevention of Dry Cracking of Excavated Earthen Sites at Han Yangling Museum Using Ultrasonic Wetting

Dry cracking is the most perilous weathering process threatening the structural stability of earthen sites. Even in a high-humidity environment, dry cracking resulting from soil water evaporation cannot be entirely prevented. This study examined use of an ultrasonic atomization system to create an atmosphere of water-mist above excavated earthen sites. This system was selected to facilitate liquid water transport from air to the soil, to prevent dry cracking of earthen sites. A validation experiment was conducted to assess the effectiveness of the system for wetting earthen sites. The experimental results revealed that the system could maintain a high water content at an excavated earthen sites with a minimal gradient in soil water content and significantly reduced salt concentrations in the soil surface layer. The HYDRUS-2D model was calibrated using 15 d of experimental data, enabling numerical simulation of water and salt transport at an excavated earthen site under various wetting scenarios for a one-year period. The simulations demonstrated a steady increase in water content and a gradual decrease in the water content gradient at the excavated earthen site when short wetting intervals were used, thereby enhancing the structural stability of the site. These findings offer a vital reference for the application of ultrasonic atomization in the wetting of excavated earthen sites to prevent dry cracking.