An integrated method for dynamic prediction of lithological composition in large-diameter slurry shield tunnels

Accurate acquisition of the lithological composition of a tunnel face is crucial for efficient tunneling and hazard prevention in large-diameter slurry shield tunnels. While widely applied, current data-driven methods often face challenges such as indirect prediction, data sparsity, and data drift, which limit their accuracy and generalizability. This study develops an integrated method that combines a knowledge-driven method to directly compute distribution patterns of lithological components, which are used as a priori knowledge to guide the development of a data-driven method. Coupled Markov chain (CMC) and deep neural networks (DNNs) serve as the knowledge-driven and data-driven components, respectively. Additionally, a dynamic prediction strategy is proposed, where the model is continuously optimized as construction progresses and training samples accumulate, rather than being statically trained on post-construction data, as is common in data-driven methods. Finally, the proposed method is evaluated using a real-world project. The evaluation results show that the integrated method outperforms both individual data- and knowledge-driven methods, demonstrating higher predictive performance, greater stability, and greater robustness to data scarcity and data drift. Furthermore, the dynamic prediction strategy better captures the effects of gradual data accumulation and lithological spatial variability on prediction performance during construction, providing new insights for real-time prediction in practical tunneling applications.