Based on the field measuring data of metro line 1 of a
city in soft soil area, the disease state and crack patterns of the whole line
and a typical section in soft soil area are statistically analyzed. The
statistical results show that the distribution of the cracks is demonstrably
related to the convergence displacement of the tunnel, and the longitudinal
cracks are the main disease in metro section, while they is densely distributed
on the tunnel crown and related to the rotation angle of the segment ring. On
this basis, a layerstructure numerical model is
established using nonlinear numerical analysis method of fracture mechanics so
as to analyze the adverse effects of weak ground conditions on tunnel rings.
The smeared crack model and simplified reinforcement grid elements are used in
model segment, while the longitudinal joint is simulated by the gap contact
model considering the joint opening. The calculating results illustrate the
cracking characteristics of the segment and its influencing factors. The
results show the following. (1) The tunnel damage area increases significantly
under insitu stress condition with decreasing elastic
modulus and lateral pressure coefficient of surrounding soil. (2) The depth of
current crack zone and predicted crack zone further expands on the original
basis with increasing burial depth, resulting in an increase in overall crack
rate. (3) The parameter analysis reveals that the main cause for the crack
pattern on the tunnel crown is the position of the key segment.
XIE Jiachong
,
WANG Jinchang
,
HUANG Weiming
,
ZHAO Jieli
,
QI Xingxin
. Analysis on Cracking Characteristic of TBM Tunnel
Lining in Soft Soil Area and Its Influencing Factors[J]. Tunnel Construction, 2020
, 40(S2)
: 180
-187
.
DOI: 10.3973/j.issn.2096-4498.2020.S2.023
