To determine the variation laws of segment dislocation
caused by the buoyancy of synchronous grouting slurry during shield tunneling,
a method for the calculation of segment dislocation is proposed, starting with
an analysis of the integral forced status and ending with the calculation of
local deformation, based on a largediameter shield tunnel
project. Then, via numerical and comparative analysis, a longitudinal analysis
model of the shield tunnel during the construction period and a threedimensional(3D) calculation model of segment dislocation are
established to calculate segment dislocation under different cover depths,
grout densities, and grout solidification times. The results indicate the
following. (1) It is reasonable to use the longitudinal analysis model of the
shield tunnel during construction to calculate the longitudinal structural
inner forces and then substitute the force boundary conditions into the 3D
segment dislocation calculation model to determine the amount of segment dislocation.
(2) As the segment ring exits the shield tail, it is subjected to the buoyancy
of the grouting liquid and the buoyancy of the surrounding water, resulting in
negative bending and maximum shear strain, which is prone to ring dislocation.
(3) The segment dislocation laws are as follows: it begins with an upward
stagger, followed by a downward stagger after passing through stable segments,
and it eventually enters the stable stage. (4) The slurry′s qualities have a considerable impact on the occurrence of
dislocation during tunnel construction. Dislocation between rings can be
effectively decreased by lowering the density of the slurry and increasing the
rate of solidification. (5) As the tunnel cover depth increases, segmental ring
dislocation is reduced due to the increase in the overlying stress and the
improved surrounding rock properties. As a result, greater attention should be
paid to the occurrence of segment dislocation in shield tunnels with a shallow
cover depth.
XIAO Mingqing
,
FENG Kun
,
ZHNAG Yi
,
ZHOU Ziyang
.
Analysis of Segment Dislocation Caused by Grout
Buoyancy during Synchronous
Grouting of Shield Tunnels
[J]. Tunnel Construction, 2021
, 41(12)
: 2048
-2057
.
DOI: 10.3973/j.issn.2096-4498.2021.12.004
