Boone Dam - Observations of LMG Grouting in Clay-PPT Presentation

PPT Presentation

Pdf Summary

The Boone Dam internal erosion remediation project conducted test grouting to develop safe drilling and grouting procedures, identify risks, and assess whether low-mobility grout (LMG) could support cutoff-wall construction or help ease short-term reservoir restrictions.<br /><br />A test pit was used to evaluate 10 grout mixes and delivery methods, focusing on grout mobility and the effects of fly ash, manufactured sand, bentonite, and slump, as well as swivel versus sweep delivery. Findings showed that grout gradation requires both a gradation envelope and a controlled uniformity coefficient. Fly ash increased mobility, while low-friction or high-slump mixes could cause hydrofracturing and continue exerting pressure on lower stages. A single mix with variable slump could meet displacement-grouting objectives, provided a suitable transition or sweep was used at the top of the casing.<br /><br />Three instrumented test cells assessed drilling and grouting risks in soil and epikarst, including heave, hydrofracture, lateral deformation, and pore-pressure response. Monitoring also supported development of grouting cutoff criteria and selection of production methods.<br /><br />Testing found that soft epikarst soils can be displaced over substantial distances and may transmit grout pressures far from the injection point. Displacement grouting can significantly alter seepage patterns and may cause harm if pressure, injection rate, and volume are not carefully controlled. Interpreting results is also difficult when multiple variables are not isolated.

Keywords

Boone Dam

internal erosion

test grouting

low-mobility grout

cutoff wall

fly ash

epikarst

hydrofracturing

displacement grouting

grout mobility