The fatigue resistance of field welds on the
cutterhead of super-large-diameter shields is critical for shield tunneling. In this study, a
finite element model of a super-thick steel butt joint,
including the weld details, is established, with the weld stress concentrated
into the toe stress and core parameter representing the equivalent structural
stress. The multi-axis fatigue life of a joint with
different groove angles and residual heights is then calculated to determine
the influence of the groove angle and residual height on the fatigue life of
super-thick plate welds. Finally, a sub-model, including a local fine mesh of welds, is established using
sub-model technology based on the optimal dimension
parameters of the welds. The fatigue lives of the welds installed by the
cutterhead are comprehensively evaluated using an equivalent structural stress
method. The results are summarized as follows. (1) The fatigue resistance
initially increases and then decreases with increasing weld groove angle, and a
groove angle of approximately 55° is the optimum for
designing symmetrical X-shaped joints. (2) When the
joint adopts an asymmetric X-groove, the fatigue life
of the toe at the small end of the weld is lower than that at the big end of
the same groove angle, and the fatigue resistance of the asymmetric X-groove joint can be improved by selecting 40° and 55° at the big and small ends,
respectively. (3) The influence of the weld residual height on the fatigue
performance of the joint is not as significant as that of the groove angle. The
residual height of the symmetrical and asymmetric X-groove
welds at the big end is 2－3 mm, and the residual height
of the asymmetric X-groove at the small end is 1 mm,
which meets the anti-fatigue design requirements of the
shield cutterhead.
WANG Defu
.
Anti-Fatigue Design of Field Welds of Shield Cutterheads Based on Structural Stress Method
[J]. Tunnel Construction, 2024
, 44(6)
: 1313
-1319
.
DOI: 10.3973/j.issn.2096-4498.2024.06.018
