Building Construction Handbook, Eighth Edition

Soil Nailing ~ a cost effective geotechnic process used for

retaining large soil slopes, notably highway and railway

embankments.

Function ~ after excavating and removing the natural slope

support, the remaining wedge of exposed unstable soil is pinned or

nailed back with tendons into stable soil behind the potential slip

plane.

Types of Soil Nails or Tendons ~

• Solid deformed steel rods up to 50 mm in diameter, located in
  bore holes up to 100 mm in diameter. Cement grout is
  pressurised into the void around the rods.


• Hollow steel, typically 100 mm diameter tubes with an
  expendable auger attached. Cement grout is injected into the
  tube during boring to be ejected through purpose-made holes
  in the auger.


• Solid glass reinforced plastic (GRP) with resin grouts.

Embankment Treatment ~ the exposed surface is faced with a

plastic coated wire mesh to fit over the ends of the tendons. A

steel head plate is fitted over and centrally bolted to each

projecting tendon, followed by spray concreting to the whole face.

Typical Application ~

soil nails at 10ƒ incline, 1.5 to 2.5 m

spacing and at up to 20 m depth

unstable soil

plant mounted drilling rig

natural support

angle of soil

70ƒ cut

potential slip

plane

tendon

Soil Nailing