A Review of Research Progress on the Deterioration Mechanisms and Conservation Treatments of Earthen Heritage Sites in China

As tangible witnesses and cultural carriers of the evolution of Chinese civilization, earthen heritage sites embody outstanding historical, cultural, and scientific value. However, due to the heterogeneity among sites and their long-term exposure to complex environmental and anthropogenic pressures, their conservation faces numerous challenges. This paper provides a comprehensive review of the deterioration mechanisms of earthen heritage sites in China induced by environmental and anthropogenic factors, with particular emphasis on the effects of individual factors, such as salt-induced erosion, wetting–drying cycles, wind erosion, microbial activity, freeze–thaw cycles, and human activities, as well as the coupled actions of multiple factors. It further summarizes recent progress in protective technologies developed in response to these mechanisms, as well as integrated conservation strategies for coping with coupled deterioration effects. In recent years, the intrinsic linkage mechanisms between external environmental conditions and the engineering performance of earthen heritage sites have become a research focus. This review aims to deepen the understanding of environmental degradation processes in earthen heritage sites and to provide theoretical and technical support for the scientific formulation of targeted preventive conservation, repair, and strengthening measures.