River Bed Regulation and Bank Protection Of Cakit Valley On Golcuk-Pozantı Motorway (Km: 351+000)
The top picture, already appeared in another context in these pages, shows an example of bank protection both by rip-rap and reinforced concrete cantilever walls. The stream in Kirkgecit Valley has a calculated runoff flow rate of 300 cubic meters/second and as is clear from view and drawing above, would create a serious threat for the motorway embankment if left unprotected. The cantilever walls appearing at two sections, have the double duty of both confining the motorway embankment from intruding into river bed and protecting it against the flow. The other bank sections where the river main flow line is more away are protected only by rip-rap. The same type of protection applied also to river bed all along the section length. In this case also, the design was based on US, Corps of Engineers practice and the sharply curved section at about the tunnel entrance portals required use of stones heavier than 1 ton.
