GS Littlejohn, BSc(Eng), PhD, CEng, FICE, MIStructE, FGS. This paper was first published in GE’s May 1985 edition.
Once the purpose of grouting, choice of grout and hole pattern have been defined, open grout holes are drilled and prepared for treatment or alternatively the grouting pipes are drilled or jetted to the appropriate depth.
Grout is normally introduced into the ground in one of four ways, choice being dictated by ground conditions and the degree of control required for grout placement into different horizons.
(i) Into an open hole in self supporting ground through pipes caulked at the surface.
(ii) Through an injection pipe held in place in the hole or casing by a packer (Fig. 18).
(iii) From a pipe driven into the ground and withdrawn as injection proceeds (Fig. 1).
(iv) Through a pipe left in place in the ground, as with a tube B manchette (Fig. 2).