Problems with interpretation of sand state from cone penetration test
Considerable attention has been given to the inference of sand density from indirect tests, particularly the cone penetration test (CPT). Data from tests performed in large-scale chambers have demonstrated that for a given sand there is an approximately unique relationship between CPT tip resistance...
| Published in: | Géotechnique |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Thomas Telford Ltd.
1989
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| Online Access: | http://dx.doi.org/10.1680/geot.1989.39.2.323 https://www.icevirtuallibrary.com/doi/pdf/10.1680/geot.1989.39.2.323 |
| Summary: | Considerable attention has been given to the inference of sand density from indirect tests, particularly the cone penetration test (CPT). Data from tests performed in large-scale chambers have demonstrated that for a given sand there is an approximately unique relationship between CPT tip resistance, density (or void ratio) and effective stress level. Data have been presented to support the supposition that CPT tip resistance, if normalized by division by the mean effective stress, is uniquely related to the difference between the current void ratio and the void ratio at the steady state at the same mean stress level. The Paper presents a study of chamber test data for the Ticino sand and demonstrates that there is no such unique relationship for this sand. Use of published correlations that fail to recognize this and other potentially important factors could result in interpretations of sand state that, if carried through to design, could in some circumstances be catastrophic. A series of flow slides that occurred during the construction of an hydraulically placed subsea sand berm at Nerlerk, in the Canadian Beaufort Sea, highlights these difficulties and provides an opportunity to compare field performance with laboratory data. On a beaucoup étudié la détermination de la densité du sable à l'aide d'essais indirects, particulièrement a partir de l'essai de pénétration au cône. Des données obtenues au cours d'essais effectés dans des chambres de grande capacité ont démontré qu'il existe une relation à peu près unique entre la résistance à la pointe du cône, la densité (ou l'indice des vides) et le niveau effectif des contraintes. On a présenté des données d l'appui de l'hypothèse que si la résistance à la pointe est normalisée en la divisant par la contrainte effective moyenne elle est reliée de façon unique à la différence entre l'indice instantané des vides et cet indice pour l'état stationnaire et pour le même niveau moyen des contraintes. Cet article étudie les résultats d'essais effectués dans de telles ... |
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