Dynamic Nonuniform Layout Evaluation Method for Shield Tunneling Stratum Adaptability Based on Thrust Fluctuation Standard Deviation Coefficient

This study investigated a method to evaluate stratum adaptability in dynamically adapting nonequidistant layouts in shield tunneling. First, a segmented progressive reconstruction mechanism was established, with the core constraint being the minimization of phase angle adjustments between adjacent layouts. Then, based on reconstruction mechanism, an analytical optimization algorithm was implemented to achieve rapid and energy-efficient switching of layouts. Subsequently, the thrust stability coefficient (TSC) was developed to quantitatively evaluate the adaptability of different layouts. Numerical calculations and validations using field data from the Wehrhahn Line metro project in Düsseldorf, Germany, demonstrated a significant reduction in TSC values. The results show that the designed nonuniform thrust system with deformation adaptability reduced the TSC by approximately 85%, with further reductions of about 70% observed during continuous construction of segment rings. The results provide a theoretical foundation and framework for the design of dynamic reconfiguration nonequidistant thrust systems and the evaluation of stratum adaptability, offering critical technical support for intelligent tunneling equipment in underground engineering.