Industry Sector & Application:
Civil Infrastructure
Location:
Tofino, British Columbia
Featured Products:
Titan Earth Grid™, Swamp Grid™, Pyramid Grid™,Geocell
Featured Services:
Product Supply, Pre-Design Assistance
Product Category:
Soil Reinforcement & Stabilization
Project Overview
Located in Tofino, British Columbia, this public seaside walking and cycling trail needed rehabilitation. Soil conditions and properties were important considerations in the design of this construction project, as poor soil properties can either make construction impossible or lead to performance failures that can be costly.
Parks Canada required an innovative solution that would address the presence of poor subgrade soil and provide a cost-efficient approach to the project. Titan Environmental was recruited to supply products and offer design services and technical guidance to construct a mechanically stabilized earth (MSE) wall on a geogrid reinforced soil pad varying from 2.0 meters in height. Four geogrid products were used to complete the project:
- Titan Earth Grid™
- Swamp Grid™
- Pyramid Grid™
- Geocell
Using Titan products and guidance, the project was completed with efficient compaction during unfavourable weather conditions, and no special equipment was needed.
The main challenge of this project was the presence of poor subgrade soil, which would eventually cause the MSE wall to sink. A solution was needed to ensure sound structural stability and longevity of the public trail, preventing frequent rehabilitation and unnecessary investment from the Government of Canada.
Comparing MSE Wall Construction Methods
Conventional Solution
The conventional solution to the presence of poor subgrade would be to construct an MSE wall on the downslope side of the trail using steel strip, polymeric straps in stages. This would allow some soil pore pressure dissipation, and strength gain in the underlying clay between stages. Although this method would avoid the potential for adverse movements during construction and improve long-term performance of the wall, it would increase the total construction time and inflate project costs.
Titan’s Geogrid Solution
Titan proposed a superior solution that would ensure higher performance of the MSE wall, speed up construction and reduce project costs. Titan’s simple solution involved:
- Constructing a geogrid reinforced soil pad to increase the bearing capacity of the subgrade.
- Constructing the MSE wall over top of the completed soil pad using Pyramid Grid™ and geocell.
- Adding a layer of aggregate followed by paving to complete the project.
The application designed by Titan was cost effective and allowed for construction to be completed in adverse weather conditions, providing a timely solution to Parks Canada that removed the risk of costly future performance errors.
Technical Breakdown of the MSE Wall Build
The application involved a geogrid reinforced soil pad consisting of multiple layers to increase the bearing capacity of the subgrade. The base of the pad included a layer of Swamp Grid™ covered with covered with 300mm thick of 75mm minus angular crushed rock fill.
Next, Titan Earth Grid™ was placed over top with 0.6 m minimum overlaps. Compacted aggregate was repeatedly layered with Titan Earth Grid™, oriented perpendicular to the first layer to reduce the potential for overlapping of joints between layers.
Once the soil pad was completed, the wall was constructed with 6 layers of 200mm perforated geocell, then filled in with clean angular aggregate to stabilize and help with confinement and drainage. After each layer of geocell was installed, a layer of Pyramid Grid™ was placed on top. The project was completed with a layer of aggregate, followed by paving on the surface of the trail.
About Titan Geogrids
Geogrid soil reinforcement & stabilization products by Titan include the very latest in geogrids technology. Designed and manufactured in-house at ISO 9001 certified manufacturing facilities, our line of soil reinforcement & stabilization geogrids consistently meets demanding QA/QC requirements. They are continuously tested to rigorous ASTM standards both in-house and by leading independent geosynthetics laboratories in North America. The following geogrid products were used in this MSE wall application:
Titan Earth Grid™:
- Effective in increasing the bearing capacity and stabilization of low load bearing soils.
- Manufactured out of virgin polypropylene (PP) using a unique punching and drawing process.
- Engineered to be mechanically and chemically stable in aggressive soil environments and is not attacked by salt, acid, or alkali aqueous solutions .
- More Information + Product Specifications
Swamp Grid™:
- An advanced combination product consisting of the Titan Earth Grid™ heat-bonded to a long-fiber PET nonwoven geotextile.
- Offers soil reinforcement with added soil filtration, soil separation, and sub-base drainage performance.
- Extremely effective for stabilizing saturated soils that are susceptible to piping and preventing loss of imported granular material into the soft subgrade.
- More Information + Product Specifications
Pyramid Grid™:
- A uniaxial polyester (PET) geogrid manufactured with high molecular weight, high tenacity polyester yarns using a precision knitting process.
- Dimensionally stable with uniform apertures that provide significant tensile reinforcement capacity in one direction.
- Engineered to withstand both harsh construction conditions and aggressive soil environments and is unaffected by soil micro-organisms.
- More Information + Product Specifications
Geocell:
- Ideal for civil engineers when trying to find the balance between soil drainage and compaction.
- Eliminates issue of low compaction and bearing capacity with a three-dimensional cellular structure that confines soil.
- Allows for vertical and lateral water drainage for effective drainage and groundwater recharge while avoiding erosion and surface runoff.
- More Information
Titan Environmental designed and manufactured geogrids can be used for a variety of purposes, including:
- Soil reinforcement and stabilization
- Soil separation and filtration
- Asphalt reinforcement
- Mine tunnel reinforcement
- Wall and slope reinforcement
Our skill sets go far beyond product supply and installation. We are adept at customizing solutions for specific site conditions.
We have project specialists who are ready to help! Request a consultation using the form below.
Would you rather discuss over the phone? Give us a call at 1-866-327-1957