Spray film: A review of waterproof mechanism and application effect in tunnel engineering

Water seepage hazards are becoming a critical issue in tunneling. Traditional Waterproof sheet materials in composite lining structures are increasingly inadequate for complex geological conditions, leading to the rapid development of spray-applied waterproofing materials. This paper provides a comprehensive review of recent advances in spray-applied waterproofing technologies and their engineering applications. It summarizes the classification and film-forming mechanisms of different spray waterproof materials and highlights their performance advantages over traditional methods. The durability of acrylate spray film in various environments is evaluated, showing greater durability under tension than compression, and significant material changes under high SO 4 2- concentrations and freeze-thaw cycles. By investigating the mechanical properties and interface characteristics of spray film linings, the optimal thickness and interface parameters of the waterproof layer are determined. Practical case analyses identify current challenges and future research directions for spray-applied waterproofing. Future developments are expected to center on intelligent quality control technologies, multifunctional self-healing membranes, and predictive modeling of long-term durability under coupled environmental conditions.