Research on Anti-cracking and Waterproof Technology of Sidewall Concrete of Underground Metro Station under Coastal Environment Conditions

Under coastal environment conditions， the required strength and durability of sidewall concrete of Qingdao metro station are high and driving force of cracking is large. In order to ensure rigid and waterproof performance of structure and to solve shrinkage cracking problem, the evaluation method of concrete shrinkage cracking for Qingdao metro, based on multi-field coupling mechanism of “hydration-temperature-humidity-constraint”, is established, and the key influencing factors of sidewall concrete cracking risks are analyzed quantitatively. On the basis of anti-cracking performance evaluation, crack-resistant construction technical method is proposed. High crack-resistant concrete is produced based on synergistic regulation principle of hydration rate and expansion history. The complete set of crack-proof technologies integrating design, materials, construction and monitoring is formed, and the risk factor of concrete cracking can be controlled under 0.7. The field monitoring and observation results show that good crack control effect of sidewall is achieved.