Dynamic risk assessment of huge caisson foundation construction based on set pair analysis theory

To study the dynamic risk assessment of large caisson foundation in large bridges during construction, a risk assessment index system was proposed by combining risk assessment with construction monitoring. A dynamic risk assessment model was established with the five-element connection main number based on the theory of set pair analysis and the index weight determined by the analytic hierarchy process method. Taking the caisson foundation of the Wufengshan Yangtze River Bridge as an example, a dynamic risk assessment was carried out. The results show that, for the secondary dynamic risk indexes, the concrete stress index decreases to -0.47 at the 102nd working day, reflecting that the stress of the caisson concrete is complex and the risk of cracking is high. The settlement coefficient index and the height difference of four-corner index after 102 d are low, exhibiting the risk of small-scale stagnant sinking and sudden sinking. For the first-level indexes, low values of the structural stress index and the control parameter index reflect the fact of the complex stress of concrete and the extra-high risk level. The overall index fluctuates significantly after 90 working days with the lowest value of -0.09, showing the middle risk status of the caisson during sinking. © 2021, Editorial Department of Journal of Southeast University. All right reserved.