Terms and definitions of Jet Grouting@bzars@ng
Terms and definitions of Jet Grouting
The jet grouting process consists of the disaggregation of the soil or weak rock and its mixing with,
and partial replacement by, a cementing agent; the disaggregation is achieved by means of a high energy jet
of a fluid which can be the cementing agent itself .
Jet Grouted Elements
A volume of soil treated through a single borehole. The most common elements are :
_ jet grouted column : a cylindrical jet grouted element ;
_ jet grouted panel : a planar jet grouted element .
Jet Grouted Structures
An assembly of jet grouted elements which are partially or fully interlocked. The most common structures formed are :
_ Jet grouted diaphragm : a wall structure ;
_ Jet grouted slab : a horizontal structure formed by essentially vertical jet grouting ;
_ Jet grouted canopy : a structure formed by horizontal jet grouting ;
_ Jet grouted block : a three-dimensional structure.
The jet grouting process in which the disaggregation and cementation of soil are achieved by a high energy jet of
a single fluid, usually a cement grout .
Double (air) System
The jet grouting process in which the disaggregation and the cementation of soil are achieved by one high energy fluid
(usually a cement grout) assisted by an air jet shroud as a second fluid .
Double (water) System
The jet grouting process in which the disaggregation of the soil is achieved by a high energy water jet and its cementing
is simultaneously obtained by a separate grout jet .
The jet grouting process in which the disaggregation of the soil is achieved by a high energy water jet assisted by an air jet shroud,
and its cementing is simultaneously obtained by a separate grout jet .
NOTE : In special cases the water can be substituted for other appropriate liquids or suspensions .
Horizontal Jet Grouting
treatment performed from a horizontal or sub-horizontal borehole (within ± ۲۰° from the horizontal plane) .
Rotary rig able to automatically regulate the rotation and translation of the jet grouting string and tool .
Jointed rods, with simple, double or triple inner conduit, which convey the jet grouting fluid(s) to the monitor .
The tool mounted at the end of the jet grouting string, to enable jetting of the fluids into the ground .
A specially manufactured device fitted into the monitor and designed to transform the high pressure fluid flow in the
string into the high speed jet directed at the soil .
Radius of Influence
Effective distance of disaggregation of soil by the jet, measured from the axis of the monitor .
The surplus mixture of soil particles and introduced fluids arising from the jet grouting process, and normally flowing
to the ground surface via the annulus of the jetting borehole .
Jet Grouting Parameters
The jet grouting parameters are defined :
_ pressure of the fluid(s) within the jet grouting string ;
_ flow rate of the fluid(s) within the jet grouting string ;
_ grout composition ;
_ rotation speed of the jet grouting string ;
_ rate of withdrawal or insertion of the jet grouting string .
The method in which the jet grouting of an element is facilitated by a preliminary disaggregation phase, with a jet of
water and/or other fluids.
NOTE : Prejetting is also widely known as prewashing or precutting .
The sequence of work in which the jet grouted elements are constructed successively without waiting for the grout
to harden in the overlapping elements .
The sequence of work in which the execution of an overlapping element cannot commence before a specified hardening time
or achievement of predetermined strength of the adjacent elements previously constructed .
Jet Grouted Material
The material which constitutes the body of a jet grouted element .
Reinforced Jet Grouting
Jet grouted columns reinforced by steel or other high strength material .