Page 169 - Water Standards
P. 169
1) Reinforcement subsection: the ring direction reinforcement
of circular tunnels can be divided into roof arch, side arch
and bottom arch. For large diameter cross sections, further
subsections are needed, according to the process, trans⁃
portation and installation conditions. Ring direction rein⁃
forcement of the door⁃shaped tunnel can be divided into
the horizontal reinforcement in the roof arch, side wall
and bottom floor, together with the “L” reinforcement in
the side wall. The reinforcement in high side walls can be
divided into in line with the pouring height of each layer.
Axial reinforcement shall be divided according to the
length of the pouring section.
2) Reinforcement installation: all reinforcement bars shall be
in⁃situ installed. For roof arch or the side arch of circular
tunnels, the reinforcement should be installed after the
formwork is set up. For side walls in the door⁃shaped
tunnel and bottom arch in the circular tunnel, the rein⁃
forcement should be installed before the formwork is
set up.
6 Construction of formwork shall meet the following require⁃
ments:
1) Tunnel lining formwork, which can be ordinary formwork,
steel⁃formwork jack plane, sliding formwork and pulling
formwork, scraper formwork, shall be selected according
to the lining construction procedure, construction condi⁃
tions, design requirements, surrounding rock conditions
and section shape and size. For long tunnels with good sur⁃
rounding rock, a full⁃section steel⁃formwork jack plane
should be the best choice.
2) The formwork loads shall be added with the weight of the
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