Unpaved Access Road with No Subgrade Preparation | Reinforced with Tough Cell® Geocells
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This project focuses on the challenges faced by the client due to muskeg, extremely soft, and poor soil conditions, which presented a grave problem for traditional road construction. It elaborates on the Tough Cell® geocell solution, which solved key constructability concerns and helped preserve the delicate muskeg.
CORE CONCERNS:
Deep Muskeg, Poor Constructability, Reliability
APPLICATION:
Access Road
CONDITIONS:
Deep Saturated Peat
LOCATION:
July – August, 2012
PROJECT OVERVIEW
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In 2012, MEG Energy hired Paradox to build an access road that would serve as the primary route for their Christina Lake complex. As they were expanding their oil sand mining operations, the client required a road that could support the weight and traffic volume of heavy equipment and machinery.
Paradox worked with engineering consultants Stratum Logics to assess, develop and successfully build an access road that satisfied the client’s requirements for an all-weather road that could support 500,000 ESALS.
THE MISSION
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The goal was to construct a stable and durable road that would increase the bearing strength of the road base, with minimal natural soil disturbance.
CHALLENGE ACCEPTED
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Paradox successfully completed the road before winter. As the existing soil in the area consisted of muskeg that was more than 1 meter deep (<1% CBR), with a moisture content greater than 800%, Paradox relied on their engineering partner to design the build to be executed over the deep peat.
THE PROBLEM
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The saturated, organic soil in this region, combined with harsh climate conditions, made conventional roadbuilding difficult at best. Freezing in the winter, heavy rains, and poor drainage in the summer typically impeded construction efforts year-round.
Paradox proposed a Tough Cell® design solution that would eliminate the need for excavation and backfill before the build. This cellular confinement technology allowed for construction over the existing deep muskeg/peat soil and increased the modulus (strength) of the existing subgrade. Additionally, locally available materials for infill were perfect as it fit within the client’s budget.
An incredible milestone!”
Intended to only last for a six month period,
the Phase 3A Access Road remains in excellent condition today and is in
frequent use ten years later.
PROJECT AT A GLANCE
Condition of access route through muskeg/peat
First layer of Tough Cell® installed, ready for sand infill
Drainage installed
Second layer of Tough Cell® infilled with gravel
Final compaction of the finished road surface
Completed access road
PROJECT SPECS
TOTAL AREA
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3.2km x 8m
36,000m2
Access Road
PRODUCT
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330-150
Tough Cell®
2 layers of NPA Geocell
INFILL
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175mm
Gravel
PEAT SAVED
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57,600m3
GRAVEL SAVED
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32,000 tons
CO2E SAVED
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1,633,276kg
By building over peat and using less gravel
THE SOLUTION
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The design consisted of two layers of Tough Cell® NPA geocells placed over the muskeg. The first layer was filled with up to 1m of clean local sand stabilizing the subgrade and improving its bearing capacity.
The second layer of Tough Cell® was then placed on top of the first (separated by a non-woven geotextile layer) that was infilled with crushed gravel. This distributed the load horizontally to reduce stress and settlement.
THE BENEFITS
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COST SAVINGS:
The client gained significant cost savings by utilizing cheaper, locally sourced aggregate. This reduced hauling and infill costs significantly.
ACCESSIBILITY:
With the new road built, Paradox was able to connect the sites for the client’s new wells, processing, operations, storage and treatment facilities, creating easy access that didn’t previously exist.
SUSTAINABILITY:
The client reduced the environmental impact by leaving the peat in place, and reducing the amount of aggregate fill needed. This reduced CO2e emissions.