Rainfall influence and risk analysis on the mural deterioration of Dunhuang Mogao Grottoes, China

Abstract The Dunhuang Mogao Grottoes are a significant cultural heritage site in the Silk Road, famous for its wonderful murals and statues. The rainfall causes the changes of humidity in the caves, which can easily activate the salts diseases of murals. In order to prevent the deterioration of the murals, the environmental monitoring tests were conducted to analyze the microclimate changes of the cave in rainfall weather, and proposed the risk prevention measures and suggestions. The results indicate that the temperature of caves has small change, but the humidity shows a clear trend of increase. The humidity and the duration of high humidity increases with the increase of the rainfall grade and frequency. The optimal starting time for environment control in the cave is when a atm and a cave are consistent, and the relative humidity is controlled below 62%. The caves with lower layer, larger degree of openness and small volume are most vulnerable to water vapour diffusion. The environment monitoring should pay more attention to the continuous rainfall weather and the vulnerable caves. The research has great significance for the prevention of ancient mural deterioration

A Numerical Study of the Effect of Vegetative Windbreak on Wind Erosion over Complex Terrain

Wind erosion is a typical issue for stone carvings in northwest China caves, and windbreaks such as shelterbelts have proven to be effective in mitigating wind erosion. This study has the main purpose of examining the effect of shelterbelts on alleviating the wind erosion degree of stone carvings. The applicability of the canopy model for reproducing the aerodynamic effects based on the realizable k–ε and LES model was examined by using a validation metric. The shelterbelt structure has been discussed with the goal of finding the optimum canopy structure to provide a guideline for designing shelterbelts. Compared with the LES model, the realizable k–ε model was adopted in this study based on its comprehensive performance. The results show that a canopy with porosity of φ = 30% and a width of 0.3 to 0.5 H has better sheltering efficiency. Compared to the case with no shelterbelt, the wind speed amplification coefficient decreased by 43%, and the significant decrease in the value of the wind speed amplification coefficient in the primary-harm wind direction demonstrates the effectiveness of the shelterbelt. By exploring preventive protection technology in the context of historical stone carving, this study can promote the practice of scientific and technological protection of cultural relics