Jet grouting improves the mechanical
characteristics of the soil by using a fluid
jetting with very high kinetic energy that breaks
up the soil structure and mixes the soil particle
in-situ with a grout to create a homogeneous mass
of high strength.
The fluid consists in grout, sometimes with water
and/or air to erode the in-situ soil Installation
comprises to position the rig, drill a small hole
(70 to 120 mm) through the layers to treat, pump
grout with a very high flow (200 to 400 L/min) and
velocity using a high pressure pump, and then
grout exists the drilling rod through small
nozzles located at the tip, and finally to slowly
withdraw the tool.
Typically, columns are 0.8 to 3.5 m diameter,
average strength 2 MPa for clayey soils and 5 MPa
for sandy soils, and treatment depth up to 40 m
Jet grouting is used in any type of soft soils,
from soft clays to sand and gravels (suitable for
stiffer material than DSM) Applications are
densification of granular soils, raising settled
structures, settlement control, underpinning of
existing foundations, excavation support,
protection of structures during tunnelling,
liquefaction mitigation, water control etc.