Discussion of “Influence of particle size on the correlation between shear wave velocity and cone tip resistance”1Appears in the Canadian Geotechnical Journal, 48(4): 599–615 [doi: 10.1139/t10-092].

The authors have presented an excellent set of cone penetration test (CPT) and shear wave velocity data from the Péribonka dam site for Holocene-age gravelly sand.The dataset adds to a growing library of similar data.It was somewhat unfortunate that the authors did not compare their data with earlier correlations suggested by Andrus et al. (2007) andRobertson (2009).It would appear that the authors had submitted their manuscript prior to the publication of Robertson (2009).The following discussion compares the relationship given by Karray et al. ( 2011) with those suggested by Andrus et al. (2007) and Robertson (2009) and comments on the influence of grain size.Andrus et al. ( 2007) developed a relationship between normalized shear wave velocity, V s1 , and normalized cone tip resistance, q c1N , using 229 data pairs from a wide range of soil types and geologic ages.The resulting relationships used the CPT-based soil behavior type, I c , as a measure of soil type and showed a strong influence of soil age.Robertson (2009) developed a similar relationship using 1035 data pairs from a wide range of soil types, but limited to Holocene-and Pleistocene-age soils.Robertson (2009) had used the more general form for the normalized cone tip resistance, Q tn , defined by