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160 Barry’s Advanced Construction of Buildings
(a) Diaphragm wall constructed in alternate panels
using a clam grab
Water can seep through joints
600–1500 mm
Wall segments excavated in alternate Approx. 5 m
segments with clam grab. Bentonite slurry
provides support until concrete placed
(b) Diaphragm wall using tube
technique
Steel tubes temporarily positioned
at each end of the wall segment
Material excavated and concrete
poured through bentonite slurry
Once the concrete has reached a
sufficient strength, the steel tube is
removed and grout is used to fill the
void
(c) Precast wall with interlocking joints
Cement slurryfills joints
Precast concrete panels with
interlocking concrete joints can be
lowered (though the bentonite) into
the excavated trench
Once the unit is positioned, cement
slurry surrounds the units and fills
the joints
(d) Diaphragm wall with interlocking joints
(hydrofraise method)
Using a specialist rig (hydrofraise machine), the
in situ concrete wall can be cut to provide an
interlocking diaphragm wall
Figure 3.76 Diaphragm walls.