Liquefaction Potential of Carbonate Sands

Liquefaction – the rapid transfer of soil interparticle stress onto pore fluid that leaves particles temporarily floating – can occur during rapid loading of sands, either cyclically (e.g. earthquake) or monotonically (e.g. during piledriving). Conventional understanding of liquefaction has developed through, predominantly, laboratory experimentation and physical modelling using silica sands (i.e. small rocks). However, during Dr Brennan’s recent post-earthquake reconnaissance visit to examine liquefaction in Indonesia, it was found that both silica and carbonate sands were present but liquefaction was only identified in silica sands. Carbonate sands, comprising crushed shells and bones etc., differ mechanically from silica sands in two ways (i) particles break at much lower stress levels (ii) particle shape.