Permeation grouting is a technique used to improve the quality of loose, unstable or water-bearing soils using resin based grout to fill the pores between solid particles in a permeable soil. This technique is generally used to strengthen and stiffen the ground but is also useful in preventing water ingress into excavations.
The resins used are carefully selected to improve the engineering properties of the ground without causing expansion (heave) or creating ‘hard spots’. Stabilised soil can be subsequently removed using traditional excavation techniques and machinery.
The use of permeation grouting can assist in the safe and expeditious formation of excavations in difficult ground conditions and can mitigate the effects of ground movement during basement construction. However, as the process of grouting involves a high degree of skill on site, a full understanding of the ground conditions and an appreciation of the final engineering requirements are required. It follows that permeation grouting should only be carried out by specialist companies working in co-operation with suitably qualified and experienced structural engineers.