To examine the mechanical
response of a metro shield tunnel during the construction of a cross-passage using the front-traction pipe
jacking method, a finite element model based on a Beijing metro shield tunnel
is established to simulate the construction process. The model′s accuracy is validated by comparing simulation results with field
monitoring data. The effects of cross-passage
construction on the dislocations between rings, stress and deformation of
special segments, and bolt force are studied. Meanwhile, the effect of
different reaction modes on the mechanical characteristics of shield tunnel are
analyzed. Key findings include the following. (1) Opening a special segment
significantly affects the mechanical properties of the shield tunnel; the stress
and deformation increase gradually with the excavation of the cross-passage. (2) The maximum displacement between segments is recorded
as 1.17 mm, occurring at the bottom of the joint between the special and
ordinary segments. The highest tensile stress in the special segment is 18.6 MPa at the top
and bottom of the opening, whereas the maximum compressive stress is 27.0 MPa
at the waist of the opening. The maximum transverse expansion and vertical
convergence displacement of the special segment are 2.13 and 4.56 mm,
respectively, with the inter-ring bolt experiencing a
maximum tensile stress of 213 MPa. (3) The backthrust
reaction mode proves more effective in controlling the horizontal and vertical
displacement at the opening, whereas the front-traction
reaction mode better manages the stress and deformation of the segment and the
dislocation between rings opposite the opening.
ZHANG Mingju
,
KANG Bo
,
LI Pengfei
,
PANG Yuekui
,
WANG Xijun
,
WU Hao
. Influence of Cross-Passage Construction Using Front-Traction
Pipe Jacking Method on Mechanical Properties of Metro
Shield Tunnel[J]. Tunnel Construction, 2024
, 44(6)
: 1165
-1173
.
DOI: 10.3973/j.issn.2096-4498.2024.06.004
