Energy measurements and correlations of the standard penetration test (SPT) and the becker penetration test (BPT)
Notice bibliographique
Résumé
The Standard penetration test (SPT) and the Becker penetration test (BPT) are two of the most widely used in-situ tests in North America. The SPT is most commonly used in sands and silty sands, while the BPT, being a large-scale penetration test, is more useful in gravelly soils. Both tests involve hammer impact on penetration rods, and the resulting penetration resistance or blow count is strongly influenced by the amount of hammer energy actually transferred into the drill rods. To make use of the large world-wide foundation performance data base currently available for the SPT, the BPT blow counts are commonly correlated to the SPT blow counts. Most of the existing correlations, however, have limited applications since they do not take into account the inherently variable output of the diesel hammer used in the Becker system and they ignore the soil friction acting on the Becker casing during driving. This research shows that the existing methods of SPT and BPT energy calibrations have serious shortcomings, and that a more fundamental approach of determining the transferred energy, based on force and acceleration measurements, should be adopted for both tests. The proposed approach provides a unified method of measuring transferred energy in the SPT and BPT, similar in principle to that currently used in dynamic testing of piles. At four research sites in Greater Vancouver, SPTs, BPTs and electric cone penetration tests were conducted. Dynamic measurements were also carried out which included force and acceleration near the top of the drill rods or pipes in the SPT and BPT, as well as bounce-chamber and combustion-chamber pressures in the double-acting diesel hammer during the BPT. An energy approach for correcting the measured BPT blow count to a reference energy level, similar in concept to that used for the SPT, is proposed. Factors affecting the BPT blow counts are investigated including hammer combustion conditions, different drill rigs, and different pipe sizes. The test results confirm that the measured transferred energy is a fundamental and useful parameter for normalizing the BPT blow counts to account for the variable energy output of the diesel hammer. The effect of casing friction in the BPT is investigated by field measurements and numerical analyses. New BPT-SPT correlations are proposed which consider the energy transfer in both tests and which, for the first time, account for casing friction in the BPT. It is shown that the proposed BPT-SPT correlations provide a rational framework for determining equivalent SPTN60 values from measured BPT blow counts, and can be applied with some confidence to gravel sites for which the BPT has proven to be a most practical and economical testing technique.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,005 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,003 | 0,003 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».