Dr. Long and co-authors receive John Mitchell Medal


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The significant contribution "Retaining Walls in Dublin Boulder Clay, Ireland" by Michael Long, Carl Brangan, Christopher Menkiti, Michael Looby and Patrick Casey to the ICE Geotechnical journal has received the John Mitchell medal. The synopsis of the paper is as follows: A good number of deep excavations have been recently completed in Dublin Boulder Clay. These have included propped walls up to 25 m deep and permanent cantilevers 7.5 m high. Experience elsewhere in the world was used to design and construct these walls. However case history data has shown that the behaviour of the walls in Dublin Boulder Clay is very rigid and much stiffer than comparable systems world – wide. It appears this behaviour is due to the inherent natural strength and stiffness of the soil and the slow dissipation of excavation induced depressed pore pressures or suctions. There appears to be scope for developing more efficient designs and in particular for reducing propping requirements. For temporary works, the use of undrained parameters in serviceability limit state calculations together with implementation of the observational approach on site could be considered for future schemes. Full paper can be downloaded here.