Shear-wave velocity based evaluation of liquefaction resistance of calcareous sands of different origin

This paper presents the results of an experimental research carried out in laboratory aimed at establishing a relationship between cyclic liquefaction resistance (CRRfield) and corrected shear wave velocity (VS1) of carbonate sands. Two carbonate skeletal sands, namely Quiou and Dubai, were investigated together with a carbonate non-skeletal sand from Kenya. The programme included also tests on two silica sands prepared and tested in similar conditions for comparison purposes. The research was based on undrained cyclic simple shear tests and bender element tests in triaxial cell performed on reconstituted specimens of sand at different initial density and stress states. The results obtained highlight that data points for carbonate sands are all located to the right of the currently used cyclic liquefaction resistance vs. shear wave velocity curves suggested for silica sands, implying that the latter curves should be considered non-conservative when applied to carbonate crushable sands. An insight into the effect of the initial effective vertical stress on liquefaction susceptibility of carbonate sands was presented and a stress normalization procedure was also proposed.