Analytical Prediction of Ground Settlement Induced by Shield Tunneling in Upper‐Soft and Lower‐Hard Inclined Strata

ABSTRACT The stability of shield tunneling through inclined strata composed of a soft upper layer and a hard lower layer represents a critical challenge in current underground engineering practice. This study proposes a theoretical framework for predicting surface settlement induced by shield tunneling under such geological conditions. First, a generalized model for the radial convergence of the surrounding soil is developed, and analytical expressions for the convergence center are derived for eight representative shield tunneling configurations commonly encountered in stratified ground. Next, the applicability of the classical Peck formula is evaluated using one‐dimensional linear regression analysis, tailored to the characteristics of upper‐soft and lower‐hard inclined strata. Based on this analysis, an analytical expression for surface settlement is established to account for the specific mechanical behavior of the composite strata. The proposed methodology is validated through a case study of the second Jiaozhou Bay Subsea Tunnel project in Qingdao, Shandong Province, utilizing both numerical simulations and in‐situ monitoring data. Results reveal that the maximum settlement and the offset of the settlement trough play distinct roles in shaping the overall deformation profile, with their relative significance varying across different strata configurations. These findings underscore the importance of considering both parameters in engineering practice. The proposed analytical model provides a reliable and practical tool for surface deformation prediction, offering empirical support for both real‐time assessment and preemptive risk management in shield tunneling projects.