A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Angled Pressure Relief Wells Improve Stability at Spinney Mountain Dam
Spinney Mountain Dam located near Hartsel, Colorado is a 90-foot-tall (27 m), 4125 feet long (1257 m), zoned, roller-compacted earth dam constructed in 1981. Upon first filling piezometers indicated high pore water pressures within the foundation and downstream embankment. In some cases the potentiometric surface extended well above the level of the horizontal blanket drain and even above the level of the embankment. Six vertical pressure relief wells were quickly installed to relieve the underseepage pressures. The relief well construction was relatively crude, consisting of open holes filled with pea gravel extending approximately 20 feet (6 m) into the foundation. These wells were hydraulically connected to the horizontal blanket drain, providing some relief and temporarily lowering the foundation pressures. Over the past 20 years the effectiveness of the relief wells and drains has reduced due to encrustation and clogging by calcium carbonate and manganese precipitates. Dam safety engineers identified a trend of an increasing potentiometric surface which could decrease the overall stability of the dam. The dam owner was required to study and implement improvements to maintain an acceptable potentiometric surface elevation and overall stability. As a result, several alternatives were developed with a technique of low-angle relief wells being chosen for final design and construction. Eight low-angle relief wells were installed. When construction was completed, the potentiometric surface had dropped as much as 11 feet (3 m) from the pre-construction levels. Completion of the relief well project lowered the potentiometric surface to an acceptable level and the new relief wells provide for the continuing stability of Spinney Mountain Dam.
Angled Pressure Relief Wells Improve Stability at Spinney Mountain Dam
Spinney Mountain Dam located near Hartsel, Colorado is a 90-foot-tall (27 m), 4125 feet long (1257 m), zoned, roller-compacted earth dam constructed in 1981. Upon first filling piezometers indicated high pore water pressures within the foundation and downstream embankment. In some cases the potentiometric surface extended well above the level of the horizontal blanket drain and even above the level of the embankment. Six vertical pressure relief wells were quickly installed to relieve the underseepage pressures. The relief well construction was relatively crude, consisting of open holes filled with pea gravel extending approximately 20 feet (6 m) into the foundation. These wells were hydraulically connected to the horizontal blanket drain, providing some relief and temporarily lowering the foundation pressures. Over the past 20 years the effectiveness of the relief wells and drains has reduced due to encrustation and clogging by calcium carbonate and manganese precipitates. Dam safety engineers identified a trend of an increasing potentiometric surface which could decrease the overall stability of the dam. The dam owner was required to study and implement improvements to maintain an acceptable potentiometric surface elevation and overall stability. As a result, several alternatives were developed with a technique of low-angle relief wells being chosen for final design and construction. Eight low-angle relief wells were installed. When construction was completed, the potentiometric surface had dropped as much as 11 feet (3 m) from the pre-construction levels. Completion of the relief well project lowered the potentiometric surface to an acceptable level and the new relief wells provide for the continuing stability of Spinney Mountain Dam.
Angled Pressure Relief Wells Improve Stability at Spinney Mountain Dam
McCormick, Bill (author) / Linden, Gary (author) / Hartfelder, Ted (author) / Tocher, Rich (author)
Biennial Geotechnical Seminar 2006 ; 2006 ; Denver, Colorado, United States
GEO-Volution ; 195-211
2006-11-03
Conference paper
Electronic Resource
English
Angled Pressure Relief Wells Improve Stability at Spinney Mountain Dam
| British Library Conference Proceedings | 2007
| British Library Conference Proceedings | 2019
Ground water pressure relief wells in shaft sinking
| Online Contents | 1983