From the early days of simple slurry injection to current sophisticated techniques, grouting has played, and continues to play, an important role in remediation and new construction worldwide. As new grouting technology is developed, and existing technologies are refined, the range of applications increases. This paper presents four grouting techniques – compaction, permeation, jet and soil fracture – that have particular relevance in today's global construction marketplace. A brief introduction to each technique is followed by discussion of recent advances, illustrated by case studies of applications.
Compaction grouting is the strategic injection of a low-slump mortar grout under relatively high pressure to displace and compact soil in place. This technique was pioneered on the west coast of the United States in the 1950s, and is the only grouting technique to have its roots in that country. Developed to overcome the lack of control of travel and set times associated with conventional slurry grouting, compaction grouting was first used to rectify settled structures. However, in recent years its use has also been centered on new and different applications in soils previously believed to be untreatable by this method.
Perhaps the most significant advance in the use of compaction grouting has taken place in seismic regions.
Typically, on large, relatively open sites, vibro stone column construction or dynamic compaction is used to achieve the majority of the required improvement. However, such sites may also abut, or include, surface or underground structures sensitive to the vibrations induced by these methods. Alternatively, overhead obstructions may preclude the use of large equipment. In these circumstances, compaction grouting, with its small, maneuverable and vibration-free equipment, is effective in achieving the improvement needed without adversely affecting surrounding features.