The Challenge - Access through Swamp Land

MEG Energy oil-sands mining operations at the Christina Lake complex in Alberta are undergoing a large expansion phase. The plan includes new wells, processing, operations, storage and treatment facilities, and of course new roads connecting them altogether. MEG Energy Project Canada
The problem was the Muskeg peat bog. This saturated, organic and acidic soil makes any road construction an engineering nightmare. The CBR of the soil is < 1%. Subzero temperatures and frozen bogs prevent construction in the winter, while ice/snow melt, poor drainage and heavy summer rains impede construction in the summer. Parts of the area where covered by swamp.

MEG needed a solution that would increase the road bearing strength and could be constructed before winter in all-weather conditions. The existing peat bog soil was too deep and poorly drained for soil replacement. The cost of importing infill and drainage solutions were prohibitively expensive. No other solution was feasible.

They asked Paradox Access Solutions if it could it be done. The answer was yes – they had PRS-Neoweb™.

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Paradox and the Tough-Cell®

MEG-2MEG chose Paradox Access – the PRS partner in Canada – because have the toughest geocell available. Faced with the most demanding soil and climate, MEG needed a geocell that could do the following:

  • Create working platform for construction
  • Increase subgrade bearing capacity
  • Increase moduli of upper structural layers

While HDPE geocells have been tried, they cannot meet the engineering performance required by the project: for stabilization, reinforcement, long-term design strength and environmental durability as Neoloy based PRS-Neoweb geocells. Neoloy is a novel polymeric alloy (NPA) with low creep reduction factor, high dimensional stability under thermal cycling (CTE <110 ppm/°C) and high flexural storage modulus (1150 MPa at -40°C) suitable for these challenging conditions.

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Construction

Paradox Access experts designed a reinforced road using one to three layers of PRS-Neoweb (Category-D tensile strength >22 kN/m) depending on the saturation level. The existing peat subgrade was covered with geotextiles for drainage and to prevent further mixing with the PRS-Neoweb layers.

The PRS-Neoweb was infilled with sand from locally available borrow pits and compacted. The strong hoop strength of the cells creates a “beam effect”, or semi-rigid mattress. This effect distributes vertical loads widely, reduces stress and settlement and extends the road life. The capping wearing course layer was filled with a thin layer of crushed gravel.

The end result was a reliable road that MEG Energy’s heavy rigs and other construction equipment could easily pass over.

Benefits

  • Engineered solution – beam effect for increased bearing capacity and heavy trafficking
  • Reliable performance – high tensile strength with long-term performance in extreme temperatures
  • Sustainable solution – used local sand for infill and for structural reinforcement
  • Fast, all-weather construction – rain and weather do not impede construction
  • Drainage solution – all-weather use road in saturated soils and harsh climate
  • Economical solution – use locally available sand, minimizes hauling and use of aggregate, quick construction

The bottom line is an “incredible milestone” for MEG and Paradox – “one to be proud of”. The customer was so satisfied that they decided to expand their use of PRS-Neoweb in the construction of their new roads.

For more information about unpaved roads and to see a movie see:on this project click here.

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