To address the low construction efficiency of existing
prefabricated underground stations, the authors propose a column-supported,
two-story, two-span assembled
rectangular frame structure that utilizes steel-to-sleeve connections with overflowed grout technology. The structure
comprises single-sided composite sidewalls, a cast-in-place bottom slab, prefabricated middle
slabs, composite top slabs, and prefabricated concrete columns. The
longitudinal reinforcement of the sidewalls employs steel-to-sleeve connections with overflowed grout.
Meanwhile, the reinforcements of the prefabricated columns on the upper and
lower floors use sleeve connections and are bolted to the bottom slab. A three-dimensional solid finite element model of the underground station
was developed using a finite element modeling approach. This model accurately
represents the characteristics of the prefabricated components and rebar
connections. Through pushover analysis, the authors examine how the presence of
embedment depth of longitudinal reinforcement extending from the middle and top
prefabricated slabs into the sides of the longitudinal beams affects the
mechanical performance of the prefabricated underground station. The obtained
results are compared with those of a traditional cast-in-place structure. The analysis yields the following findings: (1) The
prefabricated and cast-in-place
underground stations exhibit a mixed hinge failure mode, with plastic hinges
initially appearing at the ends of the middle columns. The load-displacement curve can be divided into four stages: elastic, yield,
peak, and ultimate. (2) At a burial depth of 3 m, the overall lateral stiffness of the prefabricated structure,
without extended reinforcement at the longitudinal beam sides of the middle and
top slabs, is 4.2% lower than that of the structure with extended
reinforcement. However, the presence of extended reinforcement has minimal
effect on the peak load-bearing capacity and ductility
of the prefabricated structure, with differences of <4%. Furthermore, the
differences in peak load-bearing capacity and ductility
between the prefabricated and cast-in-place stations are <6%. (3) At a burial depth of 10 m, the
differences in load-bearing capacity, ductility, and
stiffness between the prefabricated and cast-in-place structures are <7%. Compared to the structure at a 3 m depth, the structure at a 10-m depth
exhibits increases of 10.5%－12.7% in load-bearing capacity and 31.8%－46.3% in
stiffness, but a decrease of 14.5%－18.7% in ductility.
Overall, the proposed prefabricated underground station structure with columns
demonstrates favorable mechanical performance. The extension of longitudinal
reinforcement from the middle and top slabs into the longitudinal beam sides
has limited impact on the overall structural behavior.
HU Tianbo
,
XU Junlin
,
JIANG Jiafei
,
PAN Zhengyi
,
XUE Weichen
,
MAO Lianggen
. Pushover Analysis of a Prefabricated Column-Supported
Underground Station Using Steel-to-Sleeve Connections with Overflowed Grout[J]. Tunnel Construction, 2025
, 45(5)
: 933
-943
.
DOI: 10.3973/j.issn.2096-4498.2025.05.008
