Instrumented Packers: A Revolution In Pressure Monitoring For Rock Grouting-PPT Presentation

PPT Presentation

Pdf Summary

The presentation reviews the evolution of pressure monitoring in U.S. dam foundation rock grouting, a systematic process used to meet design objectives despite uncertainties and interacting variables such as pressure and grout viscosity. Pressure is a particularly useful variable because it can be measured and controlled.<br /><br />Early practice, illustrated by projects such as New Croton Dam (1893), Estacada Dam (1910), and Hoover Dam (1930), relied on pressure readings at the borehole collar and dial gauges. Guidance developed from the late 1950s through the 1970s introduced stage pressure as a more relevant measure. Later advances—including pressure transducers and flow meters—supported improved monitoring at projects such as Ridgeway Dam, New Waddell Dam, and Penn Forest Dam.<br /><br />The presentation emphasizes “effective pressure”: accounting for factors that affect the pressure actually applied to the grouted rock, including grout-column pressure and losses in the delivery line. Real-time monitoring at Penn Forest in 1998 helped advance this approach. Subsequent developments included instrumented packers, which measure pressure closer to the grouting stage. Projects cited include Wolf Creek Powerhouse and Boone Dam (2012), and East Branch and Rough River (2015). Instrumented packers enable effective pressure to be assessed using packer pressure while accounting for the grout column.<br /><br />Overall, pressure monitoring has progressed from collar readings to real-time, stage-specific measurements that better represent conditions at the rock being treated.

Keywords

pressure monitoring

dam foundation rock grouting

effective pressure

stage pressure

grout viscosity

pressure transducers

flow meters

instrumented packers

real-time monitoring

U.S. dam projects