A Model Characterizing Deterioration at Earthen Sites of the Ming Great Wall in Qinghai Province, China

Abstract

Several types of deterioration have developed at earthen sites of the Ming Great Wall in Qinghai Province, including cracks, gullies, collapses, sapping, and scaling off, the first four of which could threaten the wall's stability. The correlations of these types of deterioration with each other and with other factors were explored. The authors selected 16 sampling points from nine typical earthen sites of the wall to investigate its deterioration. Linear fitting of the data on the types of deterioration was conducted to determine their correlations. Then, indoor tests of these samples were systematically performed to clarify the physical, water-related, and mechanical properties of the rammed earth, and meteorological data for each county were collected. Finally, the linear fitting was carried out among the deterioration indices, engineering-related parameters of the rammed earth, and meteorological data to determine the influence of these factors on the development of each type of deterioration. This research illustrates the mechanisms involved in such deterioration and its evolution from a macro perspective.