Assessment of Empirical CPT– <i>V</i> _s Correlations using Direct‐Push Crosshole Data from Shallow New Zealand Soil Deposits

This article assesses the performance of multiple cone penetration test–shear wave velocity (CPT –V s ) correlations based on a database of over 2,100 CPT –V s data pairs obtained from co‐located shallow (≤10 m) CPT soundings and direct‐push crosshole tests in New Zealand. Data from 58 sites with Holocene and Holocene–Pleistocene soil deposits across five areas were used, encompassing coastal, riverine and volcanic depositional environments. Four widely used empirical CPT –V s correlations were applied to a combined database of Holocene deposits and trends in their performance were assessed. Across all considered correlations, the estimated V s values were biased towards underestimation, with the largest underestimates in fine‐grained soils with low cone tip resistance and sleeve friction values. When the best performing correlation was applied to databases for each area, the smallest biases were observed in areas dominated by Holocene‐aged soils, while significant underestimation of V s was observed in soils with volcanic deposits. These results underscore the need to quantify the influence of soil characteristics and different depositional environments on the reliability and applicability of empirical correlations for estimating V s .