Page 30 - Build 152

interlocking block
Figure 4
topsoil
granular ll
Interlocking block.
with soil to enable planting of creeping or trailing plants.
Segmental retaining wall
Segmental or modular block retaining walls con- sist of dry stacked (without mortar), interlocking concrete blocks. The blocks interlock at each course (see Figures 4 and 5) and are stepped back to create the batter.
Additional stability is provided by lling the hollow blocks with soil. Alternatively, shear pin systems are sometimes used to secure the blocks .
Segmental retaining walls may also have geogrid reinforcing fabric buried in layers
in the compacted back ll behind the wall to provide additional stability to the soil. These systems are referred to as mechanically stabilised embankment (MSE) walls.
Cantilever wall
Cantilever walls provide support either by the in- stallation of a wide, horizontal footing at the base or by cantilevered poles embedded in the ground.
Wide-footing cantilever walls can be constructed from in situ reinforced concrete or precast concrete masonry block with a concrete footing (see Figures 6 and 7). For masonry cantilevered walls up to 2.2 m high, the details in NZS 4229:2013 may be used for the design.
Timber cantilever walls have H5 treated timber poles embedded vertically into concrete in the ground to approximately the same depth as the height of the wall. Poles are typically installed at between 900 mm and 1200 mm centres. They project above the ground to support horizontal, H4 treated timber half rounds or interlocking
blocks interlocked and stepped back
Figure 5
topsoil
lter cloth
geotextile lter
granular ll drainage metal
Interlocked blocks in segmental retaining wall.
concrete blockwork with fully grouted cells to NZS 4210:2001
vertical reinforcing,
60 mm cover to lled side
horizontal reinforcing
75 mm cover
Figure 6
Concrete masonry retaining wall for non-cohesive granular soil.
drain
28 — February/March 2016 — Build 152