A threedimensional(3D) simulation
calculation model of structural stress is established to analyze the damage
evolution process of typical tunnel structures in silty clay and silty sand
under two deformation modes of horizontally and vertically oval shapes, to
provide a safety assessment for the Jiajiang tunnel operation in Nanjing,
China. Based on the overall stress state of the concrete, bolt, steel bar, and
structure, the control value of section convergence deformation in the
operation period is discussed. The following conclusions are drawn: (1) Under
the extreme scouring condition of 7 m in the middle river with strong
permeability, the tunnel as a whole rises 2.85 mm. The bolt stress amplitude,
which is the most sensitive, is reduced by 27.6%, and the concrete stress variation
is the least. (2) When the longitudinal differential settlement is not
considered, the structure changes to the mode of high axial compression due to
water scouring, which is beneficial to bearing capacity. (3) As the water level
increase, the vertical deformation of the tunnel increases by 0.22 mm, and the
bolt stress decreases by 3.8 MPa. Furthermore, the vertical deformation
decreases by 0.05 mm, and the bolt stress increases by 2 MPa. (4) The
comparative analysis results of different geological sections show that 10‰ and 12‰ are considered the settlement
control values for continental and middle river segments, respectively, under
the horizontally oval shape mode; whereas 9‰ under the
vertically oval shape mode. The results can be considered as reference points
for inspection, data monitoring, and structural safety state determination
during the operation of the Jiajiang tunnel.
YAN Weiyao
,
DING Hongzhi
,
ZHOU Quan
.
Stress Characteristic Analysis and Discussion of
Deformation Control Value of Underwater Shield Tunnel： a
Case Study of Jiajiang
Underwater
Shield Tunnel in Nanjing, China
[J]. Tunnel Construction, 2022
, 42(5)
: 863
-872
.
DOI: 10.3973/j.issn.2096-4498.2022.05.013
