The massive weight and size
of prefabricated structures in underground metro stations, combined with
multiple construction conditions, can lead to structural deformation, stress
reconcentration, and ultimately, structural damage. To address these challenges,
high-precision and high-spatial-resolution distributed optical
frequency domain reflectometry technology is utilized to monitor the strain
distribution within the sidewalls of underground prefabricated structures. The
authors investigate the effects of various construction conditions, including
sidewall assembly, roof slab installation, adjacent block assembly, and topsoil
backfilling, on the deformation characteristics of the sidewalls. In addition,
the effects of varying construction conditions on the strain field and bending
moment distribution in the sidewalls are quantitatively analyzed. The
contributions of each construction condition to the bending moments in the
middle and end positions of the sidewall structures are also investigated. The
results reveal the following: (1) Distributed fiber-optic
strain monitoring indicates an obvious compression bending effect on the
sidewalls during the assembly and topsoil backfilling stages. Among all
construction stages, the topsoil backfilling process emerges as the most
unfavorable for the stability of sidewall structures. (2) The support
replacement and sidewall backfilling processes cause notable increases in the
bending moment of the sidewall structure, with average increases of 42.8% and
19.3%, respectively. During the topsoil backfilling stage, bending moments in
the B1 and B2 sidewalls increase by 510% and 252%, respectively, compared to
the previous stage. (3) Bending moments at the ends and middle of the sidewalls
continuously increase with the assembly and backfilling conditions, causing
significant bending effects. The average contributions of the topsoil
backfilling stage to the bending moments in the middle, top, and bottom of the
sidewall are 70.4%, 69.4%, and 55.1%, respectively. The topsoil backfilling
contributes the most to the sidewall bending moments. Significant attention
should be paid to the influence of the top overburden soil pressure on the
structural behavior of the sidewalls of the prefabricated metro station.
HONG Chengyu
,
LIN Kaizhe
,
RAO Wei
,
CHEN Xiangsheng
,
QIU Tong
,
ZHANG Bin
,
DAI Ji
,
JIA Ke
. Monitoring Analysis of
Mechanical Characteristics of Prefabricated Structures of an Underground Metro Station During Construction Process[J]. Tunnel Construction, 2025
, 45(3)
: 511
-520
.
DOI: 10.3973/j.issn.2096-4498.2025.03.006
