Contractor Installed Filter Layer without Geofabric...how much time do I have?

[drucurl]

Hi there,

Another colleague is doing a road widening work on a coastal road.
They installed a temporary Revetment in order to prevent any interaction between the sea and their construction.
When the road is widened, some of the new highway section would be very close to the shoreline...it's almost a reclamation

One of my associates visited the site and noted that filter layer was placed directly on the backshore/sea....with no geotextile
The bay area is relatively calm with wave heights generally not exceeding 30 cm / 1 foot

I just want to know, based on your experience and judgement, how much time do they have before the sea takes the road?
I think that no matter how calm the wave climate is, the sea will erode the fines behind the revetment. The fines will travel through the filter and armour layer. This will lead to the instability of the road.

Thanks in advance for your Reponses.

 

[SlideRuleEra]

Erosion requires energy. Extreme tidal flow and wave action from storms can provide energy.
Time before the road is damaged will depend how many extreme tides and/or storms occur.

http://www.SlideRuleEra.net

 

[drucurl]

Thanks slide rule...but wouldn't the fines wash through the filter stone anyway?

 

[SlideRuleEra]

Unless there is significant water flow or wave action, what will wash the fines through the filter stone?

http://www.SlideRuleEra.net

 

[drucurl]

The earth on the landward side will constantly drain into the sea. The sea through wave and tidal action will constantly mobilize the sediment behind the filter stone

 

[SlideRuleEra]

In that case, there could be erosion. Without the geotextile, I agree that the revetment's useful life will be reduced.

http://www.SlideRuleEra.net