Treatment and stabilization of scaling-off in earthen sites based on Chinese conservation practice: a brief review

Scaling-off is a typical progressive deterioration of earthen sites. Systematic studies on the structural characteristics and treatment of scaling-off have been especially concentrated and developed in Chinese research and conservation practice. Based on published literature, representative conservation cases, technical reports, and field investigation data, this review synthesizes the development of scaling-off treatment over the past four decades. The historical development shows a shift from emergency surface consolidation using spray infiltration and drip infiltration, to diversified chemical, physical, and biological treatments, and further to structure-oriented intervention represented by electroosmotic grouting and back-pressure compaction. The main contribution of this review is to relate this technical evolution to the deepening understanding of the crusted layer–loose layer binary structure. This perspective suggests that effective scaling-off treatment should move beyond surface strengthening toward integrated stabilization of the detached body. Future research should further refine deterioration classification, clarify the applicability of different treatment measures, and strengthen long-term multi-indicator evaluation.