Stage loading of a highway embankment on tidal flats
The approach embankment to the eastern extremity of a bridge across the East River near Trenton, Nova Scotia involved construction of a 6.4 m high embankment on tidal flats. Very soft to soft slightly organic marine silts were found to underlie the tidal flats to a depth of 6–9 m where bedrock was encountered. Construction of an embankment of this height on the tidal flats would require very flat sideslopes to ensure stability. Alternatively, all or part of the silt could be removed or the embankment could be built slowly using the stage loading technique and allow the silt to consolidate and gain strength during construction of the embankment. Stage loading had a considerable economic advantage over the other alternatives and since sufficient time was available, this method was adopted.The case history of this project is presented including results of the settlement performance of the embankment and porewater pressure response in the silt. These results are compared with predicted values and conclusions are drawn regarding the stage loading technique for this particular type of application.