Adaptive Multi-ring Alternating Layout Algorithm for General Segmental Rings in Shield Tunnel

To address the problems of time-consuming and labor-intensive processes and large layout deviation in current segmental ring arrangement procedures, an adaptive multi-ring alternating layout algorithm is proposed, and the segment ring layout results are further optimized to meet the assembly requirements of staggered joints and having the top closure blocks as much as possible positioned at the arch waist. The results show: (1) The adaptive multi-ring alternating layout algorithm can effectively control segment ring layout errors. Calculation results indicate that under this algorithm, the maximum layout error and the average layout error are 29.27% and 55.12% of those under the traditional non-alternating layout algorithm, respectively; (2) Compared with the traditional non-alternating layout algorithm, under the adaptive multi-ring alternating layout algorithm, the proportion of segment rings with top closure blocks at the arch waist increases by 37.43%, and the proportion of segment rings with staggered joints increases by 122.67%, better meeting assembly requirements; (3) Compared with the multi-ring alternating algorithm with a fixed alternating interval, the adaptive alternating algorithm can automatically adjust the alternating interval size based on calculation results, significantly reducing the number of calculations and providing better error control.