Traditional open-cut cast-in-place
tunnels face challenges related to construction efficiency and labor costs. The
absence of a simplified formwork support system in assembled monolithic
structures has led to inefficiencies and poor working conditions in full-scaffold construction. To address these issues, the authors propose
a structural system and its construction techniques. Based on the design
concept of the support-free composite slab, a novel
type of assembled monolithic structure is proposed. This structure is assembled
using prefabricated bedplate reinforcement cages, lattice girder-type precast walls, and roof slabs, and then cast in place.
Recyclable corner connectors are used to provide mutual support between the
bedplate, sidewall, and roof slab. The precast slab and wall-attached enclosure serve as formwork for on-site
pouring to realize support- and formwork-free construction. In addition, the force transformation mode during
the construction and service stages is analyzed, and the roof slab and sidewall
are simplified as simply supported beams and two-dimensional
frame structures in the construction and service stages, respectively. Stress
analysis of the support-free composite slab and bearing
capacity assessment of the connecting nodes demonstrate the feasibility of the
proposed scheme. A technical and economic analysis demonstrates that the
proposed system significantly improves construction efficiency and reduces
labor costs compared with traditional open-cut cast-in-place tunnels. In addition, it
outperforms full-scaffold assembled monolithic open-cut tunnels in terms of efficiency and working conditions. It also
offers easier construction, lower cost, and better adaptability in soft soil foundation pit support.
Therefore, the proposed structure scheme offers better environmental and
economic benefits.
WANG Wenyuan
,
JIANG Hong
,
MIAO Lun
. Composite Slab Structural
System and Its Innovative Application in Support-Free Construction of Open-Cut Tunnels[J]. Tunnel Construction, 2025
, 45(3)
: 613
-622
.
DOI: 10.3973/j.issn.2096-4498.2025.03.017
