Christina Lake in Alberta is rich with oil so deep underground that specialized technology is required to drill and pump it to the surface. As part of the oil extraction at this site operated by Cenovus Energy, a 21,000 cubic meter capacity process pond was planned to contain the process water.
The process pond original design included a protective cover system on the 3H:1V slopes with an emulsified asphalt layer over a Tensar BX geogrid. However, questions related to technical feasibility and expense made the client and their engineer look for alternatives.
GEOWEB Slope Protection Solution
With the help of local geosynthetics supplier, Layfield Group, Edmonton, AB, a solution was found in the GEOWEB 3D soil confinement system. Vista IMV JV Corporation, the project engineer, presented Layfield with the original design’s evaluation and drawings and charged them with presenting a similar evaluation and drawings for an alternative solution. Layfield recommended Presto’s GEOWEB 3D system and immediately collaborated with Presto’s technical team to create a preliminary design package utilizing the GEOWEB slope system.
Pond Slope Details
Maximum Slope Angle: 18.5 degrees (3H:1V)
Maximum Slope Length: 16.7 m (55 ft)
Slope Vertical Height: 5.3 m (17.4 ft)
With all slope data considered, the new evaluation specified 150 mm (6 in) deep GEOWEB sections connected with polymer connection keys and secured with 600 mm (24 in) fiber-reinforced anchors. All components–the Geoweb material, keys and anchors are completely corrosion-resistant—an important consideration to protect against potential degradation. The available aggregate fill was not the 50 mm (2 in) clear stone originally recommended–but the GEOWEB system allows the use of lower quality aggregate fill. In this case, using an onsite aggregate/sand mix saved the project on materials and transportation.
Working through deeply cold weather ranging well below -20 degrees C, and frozen ground that made driving of numerous anchors extremely difficult–the 12,000 m2 (130,000 ft2) project was completed without any issues. Layfield representatives were onsite during installation to ensure the installing contractor received construction support.
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Layfield Group, Edmonton, AB: 780-453-6731