Reasons for sealing canals:
To limit the leak from the water transport and distribution canals, especially when they are built across the terrains with problematic soils, it is important to seal bottom and sides of canals.
We have different types of problematic soils:
• expansive soils
• dispersive soils
• collapsible soils
• soluble soils
To find a solution for these types of soils, one should prevent the water to come in contact with them, therefore using a completely sealed system is necessary.
An illustration of cracks made in concrete lining due to soil expansion.
Methodology for application of GCLs in canals passing built on problematic soil
Technical, economical and implementation considerations:
In this method one layer of GCL is placed on the soil surface and a non-reinforced concrete profile (concrete lining) is poured over it.
• This method is a completely sealed method and will eliminate the difficulties caused by problematic soils permanently.
• Installation process is fast and easy and does need a particular quality control activity.
• High mechanical strength makes the product resistant to any damage during construction and the construction activities can be done smoothly without extra caution for protecting the sealing element.
• Self healing capacity of GCL also offsets the effect of any damage during construction and provides the additional safety for the system.
• Guaranteed long term performance due to use of a natural product as main component.
• Guaranteed long term performance due to use of a natural product as main component (Bentonite & Geo textiles)
• Lower cost and better performance in comparison with other sealing options.
Technical, economical and implementation considerations for soil covered GCL solutions:
In This method a GCL layer is laid over the natural soil and one soil layer will be backfilled as a permanent load over it. The thickness of the soil layer should be 20cm.
• The type of the soil cover on side slopes and bottom is dependent on the water speed in canal which is in hand will determine the final cost of the system based on the availability of borrow material.
• In wide soil canals with low stream velocity this application is very economical.
• The feasibility should be looked at in case by case basis.
• All the before mentioned advantages of GCL is also valid in this application.