Geoweb Reinforced Road - Devon
Location: Lloydminister, Alberta
Timeframe: :June, 2009
Project Partners: Owner: Devon Canada Corp Contractor:Sherwood Brothers Supplier:Layfield
Oil and Gas producers are increasingly under pressure to explore and develop their resources in a more efficient, cost effective way. In order to cope with this more competitive landscape, construction managers at Devon Canada approached Layfield to explore different alternatives to reduce costs for lease access roads and drilling pads.They were interested in exploring innovative systems that were easy to deploy and that couldreduce the amount of aggregate as well as reduce the amount of operational maintenance required.
However, it was very important for Devon that any cost reductions did not come atthe expense of top notch performance. Devon’s access roads are typically designed to handleconstruction, drilling and completions equipment with loads of exceeding 125,000 lbs.(15,000 lbs. wheel loads)
Another challenge for Devon is that often they have to build roads over very soft subgrade such as muskeg, saturated clay or in areas where suitable fill material is either scarce or very expensive. For this application, Devon requested that Layfield design a road cross section thatcould be built over a soft clay sub-base with a CBR (California Bearing Ratio) of approximate 0.9. The Devon Construction team agreed to give Layfield an opportunity to demonstrate that newtechnologies could result in significant cost savings. The company requested Layfield todesign and supervise the installation of two test lease access roads sections located in NEAlberta near Lloydminister. The test sections where 7.6 m wide and 340 m long, and 7.6mwide by 240 m long.
Layfield recommended the use of Presto’s Geoweb load support system. Geoweb is a threedimensionalcellular structure that confines infill materials and controls shearing, lateral and vertical movement of infill materials. It also allows the use low quality and cost effective infill such as coarse sand to build roads and structures that can withstand very high loads.Geoweb increases the structural cohesion of the infill material and thus increases itseffectiveness.
Layfield designed and supplied Presto Geoweb GW30V6 and a LP45G high strength geotextile.The High strength high flow textile was new to Devon having provenits performance in the Horn River Basin the previous winter. Layfield recommended that Devon not use any aggregate in the construction of this road to prove the performance of the Geowebsystem. Instead, Layfield recommended the use of reject screening from crushing operations(coarse sand <5mm) as the infill material for the Geoweb cross section.
A small crew of 3 laborers where able to deploy the Geoweb & textile at a rate of 280m2 /hour. A small skid steer bobcat was used to spread the fill coarse sand infill material, whichwas compacted then graded to complete the project.
The design that Layfield implemented has the potential to save on infill materials, reduce the environmental impact of any site by both using reject fines as infill and reducing the amount of fill required to construct a project site. A typical cross section for a haul road over soft subgrade is approx 1.5m and that can be reduced to less than 300mm through the use of thecorrect materials such as Geoweb. The potential for savings in big projects is astronomical.
The owner has been very impressed with the performance of the cross section and is moving toward using this design and material where practical for all future lease and pad construction. Layfield demonstrated that it is possible to build long lasting roads that support very heavy loads over very soft subgrade and use less aggregate by using innovative, high tech construction materials.Ron Thompson, Construction Procurement Manager at Devon mentioned: “We did not like the material, we loved it. The roads has been performing way above our highest expectations”