To accurately predict the fatigue and service life of
the welded area of the fullface tunnel boring machine (TBM)
cutterhead, the notch stress method is adopted to study the fatigue and service
life of the welded area based on fatigue cumulative damage. First, a simplified
model is established for the cutterhead within the allowable range of error,
the cutterhead working conditions is analyzed briefly, and the external
excitation loads is obtained by programming. Second, the adaptability of the
notch stress method on the cutterhead welding structure is analyzed, the
transient dynamics simulation is performed on the entire cutterhead to obtain
the dangerous area (rib). Moreover, the virtual notch radius method is used to
establish a TBM cutterhead rib model to better reflect the detailed
characteristics of the weld. Then the submodel simulation
analysis is performed, and the stress at the weld root in the result is used as
the fatigue assessment factor. Finally, the service life of the welded
structure is conservatively estimated based on the revised SN curve combined
with the revised average stress. The results show the following: (1) The
fatigue and service life of the cutterhead can be accurately predicted by the
notch stress method. The fatigue and service life of the ribs is at the root of
the weld(minimum N=2.326×107). When the cutting distance of the
cutterhead is about 21.9 km, the welded joint will take the lead of fatigue
failure. The calculated results coincide with the actual situation. (2) During
the tunneling process of TBM, the welding area of the cutterhead is prone to different
degrees of fatigue failure, causing the TBM to lose its working ability in
advance and a large amount of unnecessary losses in the project.
JIA Wenshun, ZHU Ye, WANG Yuren, DU Chenglong, LEI Lei
.
Prediction of Fatigue and Service Life of Welded
Structure of Tunnel
Boring Machine Cutterhead
[J]. Tunnel Construction, 2021
, 41(S2)
: 360
-366
.
DOI: 10.3973/j.issn.2096-4498.2021.S2.046
