Salt enrichment and its deterioration in earthen sites in Emperor Qin’s Mausoleum Site Museum, China

Abstract

Salt enrichment in the topsoil, owing to one-way migration of moisture from earthen sites to air environment, is an important inducement to weathering of sites and relics, such as efflorescence, recess, slice-peeling, which becomes the most important challenge to the preservation of unearthed sites and relics. Further, salt enrichments in the topsoil of undulating earthen sites are usually inhomogeneous such that it is difficult to precisely prevent the deterioration from happening of salt enrichment in the topsoil. A case study of salt enrichment at the K9901 funerary pit of Emperor Qin’s Mausoleum Site Museum was conducted by soil column experiment and numerical simulation. The water and salt transport in the earthen sites were simulated and analyzed by HYDRUS software. The simulation of the salt enrichment process at the earthen sites demonstrated that the enrichment of soluble salt ions mainly occurs on the surface of rammed earth and increases annually; the salt damage at the earthen sites can be effectively delayed by taking an environmental control measure. These results provide a reference for the prevention of salt damage at earthen sites and facilitate the daily management of earthen sites.