Grouting in Difficult Soil and Weather Conditions

Abstract

Several methods of soil grouting and conventional underpinning are used to stabilize subsoils and repair the foundations of three apartment buildings. Innovative cold weather compaction grouting techniques were used in difficult soil conditions to densify poorly compacted man‐placed fill and soft organic silts beneath building foundations. Penetration grouting using a Portland cement slurry and Pozzolan (flyash) is performed to reduce permeability of the upper subsoils and to fill ineffective and detrimental building perimeter drains. A gravel intrusion jacking method is used to further density upper soils in conjunction with conventional underpinning methods. The project is unique because: (1) Techniques were used that allowed the contractor to drill and densify loose fills and soft natural soils containing cobbles and boulders; (2) the contractor was able to perform grouting and underpinning under extremely adverse weather conditions by using special equipment; and (3) occupants were able to remain in buildings during remedial construction.