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.
CHENG Chuantao, LIANG Zhi, WANG Jinchang, IWANAMI Motoi, WU Jian, ZHOU Zelin
.
Review of Seismic Design and Research Progress of Chinese and Japanese Shield Tunnel-Working Shaft Joints
[J]. Tunnel Construction, 2024
, 44(S1)
: 36
-52
.
DOI: 10.3973/j.issn.2096-4498.2024.S1.005
