Conrad Ginther, P.E. (Tennessee) will present "Drilling and Grouting as a Versatile Tool at Boone Dam" and "Instrumented Packers: Boone Dam." John Barrett, P.E. (Tennessee) will present "Dam Safety Instrumentation Performance of Boone Dam during Remediation Grouting," and Andrew Higgins (Ontario) will present "A Simple Project Information Management System for A Grout Curtain" at the International Conference on Grouting and Deep Mixing at the New Orleans Marriott in New Orleans, Louisiana on January 16 and 17, 2023.

The conference is organized by Deep Foundations Institute and International Conference Organization for Grouting with support from Geo-Institute's Grouting Committee. Attendees will be updated on the latest grouting practices, network with industry professionals, view the latest technology and services. This legacy event celebrates 40 years of grouting technology and practices, covering all types of grouting for foundation projects. Keynote lectures, technical paper presentations, and panel discussions will address advances in methods, materials, instrumentation, and control.

Topics will include anchors and piles; cement-based grouts; chemical and other grouts; dam foundation grouting, grout curtains, and cutoffs; deep mixing methods, applications, and performance testing; grouting for seepage control; highways and transportation; jet grouting; karst grouting; levees and flood walls; low mobility grouting; mine applications; permeation grouting; performance testing; structural support; and tunneling.

Abstracts

Drilling and Grouting as a Versatile Tool at Boone Dam
Conrad Ginther, P.E., Principal Engineer, Geosyntec Consultants
Sessions/Presentations: Monday, January 16, 11:15 a.m., Salon D-E
The Tennessee Valley Authority's Boone Dam was constructed in the 1950s using construction techniques for embankment dams built on karst foundations that were common to the contemporary state of the practice. These techniques included excavation of a cutoff trench to rock where the exposed limestone pinnacles were cleaned of loose, soft, or otherwise permeable materials and backfilled with compacted clay and construction of a grout curtain along the cutoff trench alignment. After a sinkhole opened near the downstream toe of the embankment and turbid water was observed exiting from the right bank of the tailrace in 2014, TVA embarked on a comprehensive remediation project to mitigate the active internal erosion failure modes including two production drilling and grouting programs, construction of rockfill berms on the upstream and downstream faces of the embankment, and construction of a concrete secant pile wall. Drilling and grouting was used in this comprehensive remediation as an interim risk reduction measure in zones of well-developed karst, as a primary treatment in groutable rock, as an exhaustive subsurface exploration program used as the design basis for the concrete cutoff wall, and as a detailed verification program to confirm the constructed cutoff wall would meet the design intent of permanently mitigating internal erosion related failure modes. This paper discusses the drilling and grouting methods employed across the phases of the project and how the data from individual grouting programs was incorporated into subsurface models, the design of subsequent phases of construction, and final acceptance of the remediation.

Instrumented Packers: Boone Dam
Conrad Ginther, P.E., Principal Engineer, Geosyntec Consultants
Sessions/Presentations: Wednesday, January 18, 10:15 a.m., Salon A-C
After completion of slurry control grouting in karst terrain at TVA's Boone Dam, TN an additional two-line high-mobility grout curtain targeting the rock at and below the base of the planned cutoff wall was performed for the purpose of confirming cutoff wall design assumptions and to provide primary treatment of the rock free of significant karst features or erodible material below the cutoff wall. The Additional Drilling and Grouting Program (ADGP) was performed using instrumented packers for all injections during pressure testing and grouting. This paper summarizes observations of the benefits and challenges encountered while using instrumented packers from the perspective of an asset owner, engineer, and contractor with respect to maintaining safe injection pressures, interpretation of grouting results, calibration and deployment in construction, and recommendations for additional research and development to further advance the state of the practice.

Dam Safety Instrumentation Performance of Boone Dam during Remediation Grouting
John Barrett, P.E., Principal Engineer, Geosyntec Consultants
Sessions/Presentations: Monday, January 16, 11:45 a.m., Salon D-E
Following observations indicative of active internal erosion in 2014, the Tennessee Valley Authority (TVA) lowered the reservoir at the Boone Hydroelectric Plant in order to reduce dam safety risks until permanent improvements could be implemented. Following investigations in 2014 and early 2015, the TVA adopted a composite seepage barrier remedial solution to mitigate long-term dam safety risks. The remediation is composed of specialty geotechnical construction techniques deep below the ground surface with the intention to significantly reduce or eliminate the risk of internal erosion through the embankment and its foundation. The composite seepage barrier was composed of low-mobility grouting (LMG), high-mobility grouting (HMG), and a concrete cutoff wall constructed by secant pile construction. The objective of this paper is to provide a case history for the performance of an embankment dam on a karst foundation undergoing preventive and remedial grouting as part of the construction of a composite seepage barrier. The paper is organized to (i) introduce the project background, objectives, and geologic setting; (ii) summarize the tools that were used to reduce seepage beneath the embankment dam, (iii) describe the foundation response through as interpreted by the extensive instrumentation program at the site; (iv) highlight the overall response and performance of the dam during the respective phases of grouting.

A Simple Project Information Management System for A Grout Curtain
Andrew Higgins, Senior Scientist, Geosyntec Consultants
Sessions/Presentations: Tuesday, January 17, 5:30 p.m., Salon A-C
Advancements in grout monitoring and data management have yielded a variety of methods of measuring and assessing data collected in grout curtain installations. However, these systems need not be complicated. Smaller grout curtain activities that may not have the benefit of modern real-time grout monitoring equipment can still use Project Information Management Systems (PIMS) technologies and principles to enable analyses, track and visualize progress, and generate reports and as-built drawings. This paper will present case studies of the applications of a simple PIMS to small grout curtains. The PIMS allows digital entry of key grouting metrics and provides an interactive dashboard and generates automated reports to identify areas with high grout takes, view injection volumes and lugeon in profile, calculate total volumes by hole series and show relationships between these (Primary, Secondary, Tertiary etc.), and more.

More Information

About the event: 6th International Conference on Grouting and Deep Mixing (xcdsystem.com).
Learn more about Conrad: Conrad Ginther, PE | LinkedIn
Learn more about John: John W. Barrett, P.E. | LinkedIn
Learn more about Andrew: Andrew Higgins | LinkedIn