Sinkhole Mitigation Using Compaction Grouting: A Case Study of Driveway Stabilization in Nashville, Tennessee-Paper

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The paper examines recurring sinkhole-related pavement failures along Whispering Hills Drive in Nashville, Tennessee. Earlier repairs involving excavation and crushed-rock backfill did not prevent renewed settlement and a roadway dropout, indicating that deeper subsurface instability remained untreated.<br /><br />Investigations included 12 boreholes, standard penetration testing, rock coring, and laboratory analyses. Results showed variable fill over soft clay and karst-prone limestone, with evidence of voids, soil piping, weathered rock, and solution channels. These conditions were consistent with ongoing subsidence in the Hermitage Formation.<br /><br />Three remediation options were assessed: an inverted rock filter, a structural land bridge, and compaction grouting. Deep excavation for the rock filter would require substantial shoring and utility relocation, while the land bridge was considered too costly and time-consuming. Compaction grouting was selected as the most practical and cost-effective alternative. The planned method injects low-mobility grout in stages to densify loose soils, fill or seal voids, and create a stabilizing cap near bedrock while preserving groundwater movement. The pavement area would then be rebuilt with engineered fill and improved drainage.<br /><br />The authors emphasize that the repair addresses the current site hazard but cannot eliminate sinkhole risk across the wider karst area. They recommend post-repair monitoring, including settlement markers and piezometers, and stress the importance of site-specific investigation, continued risk management, and coordination among engineers, utilities, authorities, and the community.

Keywords

sinkhole

pavement failure

karst

compaction grouting

subsidence

Whispering Hills Drive

Nashville

Hermitage Formation

subsurface instability

remediation