Evaluating liquefaction potential by seismic dilatometer (SDMT) accounting for aging/stress history

The seismic dilatometer (SDMT) permits to obtain two parallel independent estimates of liquefaction resistance CRR, one from the horizontal stress index Kd and one from the shear wave velocity Vs. The use of Vs for evaluating CRR is well known. Correlations CRR-Kd have been developed in the last two decades, stimulated by the recognized sensitivity of Kd to factors which are known to increase liquefaction resistance – stress history, prestraining/aging, cementation, structure – and its correlation to relative density and state parameter. This paper provides further insight into the ability of Kd to reflect aging in sands, a factor that recent research has indicated as having a first order of magnitude influence on liquefaction behaviour. In addition, recent SDMT experience has pointed out the high sensitivity of Kd to "non-textbook" OCR crusts in NC sands. These findings lend additional support to a well-based CRR-Kd correlation.