Improving Post-Earthqauke Slope Stability with Soil-Cement Shear Panels at Boiling Spring Lakes-PPT Presentation

PPT Presentation

Pdf Summary

Austin Spencer’s presentation describes the investigation and remediation of Sanford Dam at Boiling Spring Lakes, North Carolina, after Hurricane Florence in September 2018 caused the dam to fail. The dams were built in the early 1960s to support a lake-centered community.<br /><br />Geotechnical exploration in 2019–2020 included electrical resistivity imaging, soil borings and standard penetration tests, rock coring, cone penetration testing, hydraulic conductivity testing, and laboratory analyses. The regional geology includes the Castle Hayne Formation, with calcirudite and calcarenite limestone. Investigations found liquefiable soils beneath all three embankments. A semi-quantitative risk assessment led to remediation being limited to Sanford Dam.<br /><br />Potential approaches included excavation and replacement, densification, and soil-cement shear panels. The selected panels were designed to address stability risks such as overturning, bearing failure, crushing, sliding, shear through the treated zone, and soil extrusion between panels. The presentation also covers the project’s global stability analysis, panel layout, and modified embankment section.<br /><br />Construction involved site access and staging, pre-drilling, installation with a multi-axis deep-mixing tool, and quality-control sampling and testing. The specified minimum design strength was 130 psi.

Keywords

Sanford Dam

Boiling Spring Lakes

Hurricane Florence

dam remediation

geotechnical investigation

liquefiable soils

soil-cement shear panels

deep soil mixing

global stability analysis

Castle Hayne Formation