HR Wallingford: Lab Testing for Dawlish Seawall Design

During the severe winter storm of February 2014, a section of the seawall at Dawlish collapsed, destroying part of the main railway line to Devon and Cornwall and urging government to announce funding for the seawall upgrade works.

Arup, who are designing the new seawall, have commissioned HR Wallingford to conduct physical modelling tests in the laboratory to verify the performance of the proposed design.

The works for Marine Parade will see the height of the sea wall increased by 2.5 meters and include a wave parapet. This will reduce the impact of the waves, reducing the volume of overtopping water and the likelihood of the line being closed during adverse weather.

Eunice Silva, Engineer in HR Wallingford’s Coastal Structures Group, said: “Using the results from Arup’s overtopping study, we will be carrying out a whole series of 2D tests over two months in a 40m long wave flume. This will involve constructing the bathymetry, calibrating the different sea states for the different bed levels, building a scaled model of the seawall design, and then carrying out tests for different crest level and storm conditions.”

The new seawall will also have more robust foundations to secure the underlying structure.

HR Wallingford’s laboratory testing is due to be concluded by the end of April, with work on the new seawall expected to start in spring 2019 and to be completed by 2021.