Building Research Establishment (BRE) associate Andrew Charles made the call during his presentation at the 48th Rankine Lecture held on 19 March at Imperial College London.
"Is the surface inspection every 10 years of dams such as for the UK's ageing infrastructure, introduced in the 1970s, sufficient?" he said. "Shouldn't they really need a safety assessment?"
Charles queried current practise during the conclusions of his lecture: The engineering behaviour of fill – the use, misuse and disuse of case histories. The lecture centred on his assertion that for the foreseeable future, fills will have increasing significance in geotechnical engineering.
Among other issues, Charles focused on condition assessment of old embankment dams, performance of rockfill dams and the effectiveness of ground treatment.
His concluding remarks covered the critical differences between non-engineered and engineered fills, the significance of water on engineering behaviour, the condition assessment of existing structures, relevance of research and the importance of case histories with field measurements.
On this final point, Charles underlined that case studies are extremely important when backed up by theoretical understanding and judgment. He said: "Case histories are far more important within geotechnics than in any other branch of civil engineering," adding that 10bnm3 of fill is placed worldwide every year, which in context dwarfs even the 200M.m3 used for Hong Kong's Chek Lap Kok airport.
After the lecture, Imperial College London emeritus professor of soil mechanics John Burland told the audience: "Case studies help with diagnostic techniques. Time alone does not reduce collapse potential when mixed with rising water tables. Long-term monitoring programmes are vital."