Buckley, R. M., Jardine, R. J., Kontoe, S., Barbosa, P. & Schroeder, F. C. (2020). Full-scale observations of dynamic and static axial responses of offshore piles driven in chalk and tills. Géotechnique 70, No. 8, 657–681, https://doi.org/10.1680/jgeot.19.TI.001. The following mistakes have been identified. First, Figs 2 and 3 are incorrect; the correct versions of these figures are as follows.
Profiles of soil behaviour type index, Ic (Robertson, 1990), undrained shear strength, su, calculated from the CPT cone resistance assuming clay behaviour and an Nkt factor of 22·5 and yield stress ratio at: (a) WK38 and WK42; (b) WK43 and WK70
Profiles of soil behaviour type index, Ic (Robertson, 1990), undrained shear strength, su, calculated from the CPT cone resistance assuming clay behaviour and an Nkt factor of 22·5 and yield stress ratio at: (a) WK38 and WK42; (b) WK43 and WK70
Second, in the second paragraph in the right-hand column on p. 673, several of the ratio values quoted in the fourth and fifth sentences are incorrect; the correct sentences are as follows.
Open-steel piles tested at comparable ages at Dunkirk (Jardine et al., 2006) indicated a set-up factor of ≈1·9 between their 10 day and 100 day capacities which, if applied to the ICP-05 sand calculations, raises the predicted-to-measured shaft capacity ratios to 0·70<Qc/Qm<1·33 and gives an average of 0·93. Adopting any of the cited clay methods leads to large over-predictions for the resistances available in glacial till units 12–15 weeks after driving, with 1·5 (for API, 2014)<Qc/Qm<9·0 (for UWA13).
Summary of static pile capacity predictions in the glacial till
| Site | Measured* | Shaft load Qs in glacial till layer: MN | |||||
|---|---|---|---|---|---|---|---|
| ICP-05 sand† | API-2014† | Fugro-96† | NGI-05† | UWA-13† ‡ | ICP-05 clay† | ||
| WK38 | 6·07 | 2·25 (0·37) | 9·10 (1·50)§ | 10·71 (1·76)§ | 9·38 (1·55)§ | 19·38 (3·19)§ | 12·53 (2·06)§ |
| WK43 | 2·93 | 1·19 (0·41) | 7·48 (2·55) | 6·65 (2·27) | 7·52 (2·57) | 13·95 (4·76) | 8·50 (2·90) |
| WK70 | 0·90 | 0·63 (0·70) | 4·04 (4·48) | 3·48 (3·86) | 4·01 (4·45) | 8·06 (8·95) | 3·94 (4·37) |
Proportion based on static values given in Table 5.
Values in parentheses are ratios of calculated to measured capacity.
Uses UWA-13 method with inclusion of angle of interface friction (equation (8)).
Adopts ICP-05 calculation in top 2 m of Holocene sand.
Summary of static pile capacity predictions in chalk
| Long-term (>100 day) shaft load Qs in chalk layer: MN | |||
|---|---|---|---|
| Site | Measured* | CIRIA C574† | Chalk ICP-18†‡ |
| WK38 | 2·73 | 0·27 (0·10) | 3·31 (1·21) |
| WK43 | 17·97 | 1·76 (0·10) | 14·23 (0·79) |
| WK70 | 21·54 | 4·83§ (0·22) | 20·81∥ (0·97) |
Proportion based on static values given in Table 5.
Calculation assumes Δr= 0·5 μm with G calculated from equation (3).
Values in parentheses are ratios of calculated-to-measured capacity.
Adopts 120 kPa in high-density chalk/Danian limestone layer.
Adopts qt= 50 MPa in the high-density chalk/Danian limestone layer.
The authors apologise to the readers of Géotechnique for these mistakes in the original paper.
