23
V1.4 March 15
7.5.3 Post-grouting with a grout valve
Grout valves are generally used when Casing is installed in small diameter boreholes that
do not allow the use of an external grout pipe and is fitted with a non-return valve and a
male Quick Release fitting.
A grout pipe is lowered down through the centre of the Casing with a female Quick Release
fitting which attaches onto the male fitting on the grout valve. Once grouting is complete the
grout pipe is then removed.
The following steps should be carried out when post-grouting the borehole:-
1.) Flush out the borehole with clean water and check the depth.
2.) Attach the grout valve end cap to the bottom of the Casing and install to the required
depth.
3.) Add water to the Casing to counteract buoyancy and/or grout pressure.
4.) Place the grout pipe to the bottom of the borehole onto the Quick Release fitting and
pump in grout.
5.) Use the internal grout pipe to further counteract buoyancy if necessary.
6.) Remove the grout pipe, flush with water and allow the grout to set.
7.) If necessary add grout to the top of the borehole and fit a protective cover.
Grout pump
& mixer
Tremie pipe
Bentonite
cement
grout
QJ Casing
Top cap
Protective
cover
Grout valve
