Grouting patterns and possibilities with helical piers

The experimental procedures and results are presented for a one-tenth scale laboratory investigation of changes in achievable grouted zones through alterations in helical pier parameters. The parameters investigated were the location of the grouting holes with respect to the position of the helices, the grouting pressure and the rate of helical pile installation. The results showed that the total treated volume was 40% to 158% greater than the grouted volume and that the thickness of the treated zone beyond that which was strictly grout was 15% to 61% of the radius of the grouted, cross-sectional area, which was largely controlled by the diameter of the bottom helix. Increases in pressure generate non-linear improvements with increasing effectiveness at higher pressures. The placement of grout holes beneath the bottom helix was shown to be more effective in grout delivery than the standard industry practice of placing the holes above the helix.