A novel seismic-continuous geological predicting method in shield tunnels

Shield tunnels are widely adopted for their rapid construction speed and high mechanization. However, they exhibit limited adaptability in complex geological environments, highlighting the need for reliable advanced geological prediction methods. This study validates the applicability of “pre-source and post-receiving” observation system for shield tunnels, targeting the commonly used seismic detection methods. The Finite Difference results demonstrate this as one of the most appropriate systems, facilitating forward wave propagation while providing useful offset to enhance velocity analysis. Furthermore, a near-vertical incidence seismic wave excitation scheme and a dynamic acquisition strategy synchronized with tunneling are designed, resulting in a continuous dynamic predicting method featuring “bidirectional minimal offset”. Compared with conventional seismic detection approaches, this method can increase the seismic data by one order of magnitude and effectively suppress the interference caused by P-S wave conversion in the imaging. Preliminary field tests verified the feasibility and effectiveness of the proposed method, providing a new methodological foundation for advanced geological prediction in shield tunnels.