Details of compaction grouting procedure
Compaction grouting is the most recognized method that enhances the stability of the ground. It implicates the injection of very rigid grout material under a high pressure and low rate with the purpose of compacting the treated soils by drastically dislocating the soil particles into a tighter spanning.
Setting up the grout pipe: The group pipe is either set up with the use of a drill rig or a vibro hammer based on the soil & the treatment requirement.
Compaction Grouting: The grout paste is formed in the mixing plant and pushed into the soil through a custom-made grout pump. At the time of pulling or piercing the grout pipes, individual intersecting grout bulbs are continually developed and in this way the column shaped structural components are made.
Compaction 3 phases: To get a consistent compaction of the soil, initially the injections are provided in a large primary grid and compressed repeatedly with a secondary grid.
1. Hole is drilled or casing is pushed to the bottom of projected treatment zone.
2. Compaction grout is then pumped through the casing unless one of different refusal criteria are obtained.
3. Casing is upraised to the next phase and the steps 1 & 2 are reiterated.
The properties of materials used in grouting compaction
Sand – It should be abided by ASTM C-33
Cement – If cement is included, it should be Type I or Type II Portland and does not contain any stain. Cement should be delivered in waterproof paper bags or in quantity. If any lump is found, the cement should not be taken or examined thoroughly to take away.
Flyash – If flyash is applied , it should be abided by ASTM C-618 and be either class C or class F.
Lime – If lime is used, the type should be hydrated agricultural lime. Lime should be delivered in waterproof paper bags or in quantity. If lumps present in lime, it should not be taken or examined properly to take away lumps.
Water – Clean and purified water should be used. The volume should be provided to obtain the desired slump.
Admixtures – Different types of admixtures like superplastizer or a pumping aid should be included to enhance set time or make the strength of the pump better. If bentonite is used to resist bleeding and segregation, it should be hydrated.