How can the application process of concrete water-based release agent be optimized to ensure uniform coverage of the curved surface of tunnel segments?
Publish Time: 2026-03-17
In the construction of modern urban underground transportation networks, shield tunneling has become the mainstream method due to its efficiency and safety. As the core component of tunnel lining, the quality of shield segments directly determines the tunnel's waterproofing performance and structural lifespan. However, the unique curved surface of shield segments presents significant challenges to production: traditional release agent application methods are prone to accumulation and sagging at the apex of the curve or missed areas at the base, leading to air bubbles, adhesion, and even damage to the concrete surface. Optimizing the application process of concrete water-based release agent to achieve uniform coverage of the curved surface has become a key step in improving the prefabrication quality of tunnel segments.1. Coating Challenges and Fluid Combat on Curved SurfacesThe curved geometry of shield segments makes gravity a double-edged sword during the coating process. In traditional manual brushing or simple spraying, the water-based release agent, influenced by gravity, tends to flow and accumulate towards the lower parts of the curved surface. This not only results in an excessively thin or even exposed film layer at the apex of the arc, increasing the risk of mold sticking, but also leads to an excessively thick liquid film at the basal area. An excessively thick release agent layer will boil during high-temperature steam curing, forming persistent air bubbles and pores, severely damaging the density and aesthetics of the concrete surface. Furthermore, water-based release agents inherently possess high surface tension and relatively slow wetting speed; without precise control of their atomized particle size and adhesion amount, it is difficult to form a continuous and uniform microscopic release film on the smooth curved surface of the steel mold.2. Core Process: Intelligent Reciprocating Spraying and Atomized Particle Size ControlTo solve the above problems, the optimized coating process first introduces a high-precision intelligent reciprocating spraying system. This system abandons fixed-angle unidirectional spraying and adopts a multi-axis linkage robotic arm or gantry structure, ensuring that the spray gun always moves perpendicular to the tangential direction of the segment mold. Through a preset arc trajectory algorithm, the spray gun automatically adjusts its angle and distance during travel, ensuring that every inch of the curved surface receives an equal amount of droplets.3. Quantitative Closed-Loop Control and Multi-Layer Thin Coating StrategyBesides hardware upgrades, innovative control strategies are equally crucial. The optimized process introduces a flow-based closed-loop control system, precisely controlling the amount of release agent sprayed down to grams per square meter. The system calculates and dynamically adjusts the spray flow rate in real time based on the radius of curvature and surface area of the tunnel segments, eliminating the arbitrariness of human operation.4. Quality Leap: From Perfect Appearance to Durability GuaranteeThe optimized coating process not only ensures a mirror-like surface and uniform color for the tunnel segments after demolding, completely eliminating air bubbles and adhesion defects, but also significantly improves the durability of the segments. The uniform and extremely thin release agent film does not hinder the adhesion between the concrete and subsequent grouting materials, ensuring the overall waterproof and sealing performance of the tunnel. Simultaneously, the environmentally friendly characteristics of the water-based release agent, combined with precise spraying, significantly reduce chemical waste and volatile organic compound emissions, aligning with the trend of green construction.In summary, considering the unique characteristics of the curved surface of tunnel segments, the coating process of concrete water-based release agent has achieved a leap from "extensive coverage" to "precise film formation" through the comprehensive application of intelligent reciprocating spraying, atomized particle size control, quantitative closed-loop control, and a multi-layer thin-coating strategy. This process optimization not only solves the industry-wide problem of uneven coating on curved surfaces but also lays a solid manufacturing foundation for building a century-old underground Great Wall.
