Abstract: By comparing the requirements for shield tunnel-working shaft joints in Chinese and Japanese codes and standards, the current state of seismic design theories is presented. It is found that Chinese design codes for shaft joints exhibit vagueness and, in some cases, minimal references to seismic resistance; in contrast, Japanese standards encompass two seismic calculation methods for flexible joints in shield tunnel-shaft structures, showcasing more mature and practical seismic analysis theories and computational approaches. Both China and Japan afford significant freedom to design units in their respective design standards, yet the permissible value ranges lack evaluation criteria. Furthermore, the research progress in seismic analysis of shaft joints is investigated, identifying seismic characteristics and key influencing factors at shaft joint locations. Based on this,  the current status and deficiencies in shaft joint studies are proposed, focusing on key elements influencing the comprehensive response mechanism of shaft joints, including the impact of stiffness ratio, interaction among structures, effects of ground bearing capacity, and a comparative study of rigid and flexible joints. Finally, after summarizing and evaluating seismic assessment methods and measures for shaft joints, conclusions are drawn as follows: (1) The soil-structure stiffness ratio significantly affects working shaft joints, emphasizing the need to control the stiffness of the soil layer around working shafts within a reasonable range. Moreover, investigating the stiffness ratio between structures is recommended as a key area for future research. (2) The interaction between structures primarily focuses on the influence mechanism between two structures under different seismic loads. Thus, considerations for structural interaction should also be extended to the study of shield tunnel-shaft junction contact. (3) In addition to sudden changes in structural stiffness, stiffness discontinuity in foundation stiffness are also important influencing factors. While Japan has proposed a simplified evaluation formula and validated it, research in this aspect is relatively limited in China. Such research should be emphasized in soft soil areas. (4) Japan has conducted in-depth research on flexible seismic resistance. Considering that China will soon require a new standard for rigid-flexible structures for shield tunnel-working shaft joints, Japanese research results also provide a useful reference for China to further develop seismic design of shield tunnel-working shaft joints. In addition, the possible future development direction of this research field is predicted.

Key words: shield tunnel-shaft joint, seismic structural design, Chinese and Japanese seismic design standards, seismic measures