Grouting
Expertise
Grouting is used to consolidate uncompacted ground and/or for waterproofing, via boring then hit-and-miss injection.
This technique is used to improve ground in different cases:
- filling natural cavities (karsts, dissolution voids, etc.)
- filling artificial cavities (particularly underground quarries)
- re-compacting accidentally uncompacted ground (water leak, nearby groundwork, etc.)
- filling cracks in the ground to prevent water circulation (grout curtains under dams, watertight curtains around groundwork or shafts, etc.)
- sand and gravel impregnation using a liquid product that hardens after injection
- renovation of underground or engineering structures using limited drilling and low-volume grouting, plugging cracks, and restoring structural solidity (contact-restoration grouting).
Solid or liquid grouting
The injected grout fills voids in the ground, cracks in rock, and voids caused by dissolution (then referred to as crack, impregnation or cavity filling grouting), and/or penetrates by displacing the soil as a result of pressure or hydrofracturing (then referred to as compaction grouting or solid grouting, and hydrofracture grouting).
Grouting can also be “solid” and based on the principle of horizontal static soil compaction, injecting pressurised mortar to create a column that increases the density of the soil.
Grouting can also be “solid” and based on the principle of horizontal static soil compaction, injecting pressurised mortar to create a column that increases the density of the soil.
Injection grouts
The grout injected can be:
- liquid: the penetrative power of these grouts is essentially a function of the way their viscosity changes over time. Over time, they are used to impregnate granular formations.
- suspensions: in addition to viscosity, these grouts also have rigidity or cohesion, which limits their scope of action. The granularity of the slurry also limits the size of the voids or pores.
- mortars: these high-rigidity grouts are used to fill cavities and voids, or in displacement grouting: solid or compensation grouting.
- liquid: the penetrative power of these grouts is essentially a function of the way their viscosity changes over time. Over time, they are used to impregnate granular formations.
- suspensions: in addition to viscosity, these grouts also have rigidity or cohesion, which limits their scope of action. The granularity of the slurry also limits the size of the voids or pores.
- mortars: these high-rigidity grouts are used to fill cavities and voids, or in displacement grouting: solid or compensation grouting.
Computer-controlled grouting
Grouting can also be computer-controlled. The pressures, flow rates and quantities pumped are recorded in real time. The computer system controls the presses, halting the grouting process when a shutdown requirement is met: pressure limit or maximum volume.
Types of grouting
The different types of grouting:
- Compensation grouting: this is used to consolidate uncompacted ground and/or for waterproofing, via boring then hit-and-miss injection.
- Contact-restoration grouting: this it used to renovate underground or engineering structures using limited boring and low-volume grouting, plugging cracks and restoring structural solidity.
- Solid grouting: this is based on the principle of horizontal, static ground compacting. Pressurised mortar is hit-and-miss injected into a borehole, creating a column that increases the density of the ground.
- Freezing: this unusual process is used to waterproof and consolidate ground where grouting is not an option, by freezing ground water in a given area by pumping in liquid nitrogen.
