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Research on post-grouted drilled shafts has focused primarily on post-grouted tips. Here, four full-scale shaft load tests were conducted to investigate the behaviors and performance of combined tip-and-side grouted superlong and large-diameter drilled shafts in extra-thick fine sand layers. The enhanced mechanism of the combined grouted drilled shafts is analyzed, and a rational approach for analyzing their load-displacement response is presented. The side and base resistance of the combined grouted drilled shafts exhibited significant strengthening, substantially increasing the bearing capacity and effectively controlling settlement. Under the ultimate load, >60% of the shaft head displacement was caused by shaft compression; a relatively small load proportion was carried by the shaft base. The superlong and large-diameter drilled shaft can be treated as a friction shaft, and the combined tip-and-side grouting cannot change the bearing characteristics. The hyperbolic model describes the relationship between the side resistance and relative shaft-soil displacement and captures the base resistance-displacement response. The proposed approach is verified with a case history, and the bearing behaviors of a large-diameter drilled shaft under an extra-thick fine sand layer are analyzed. These results clarify the bearing characteristics of combined grouted shafts and can help guide the design of post-grouted shafts. Key words: superlong and large-diameter drilled shaft, combined tip-and-side grouting, Osterberg cell method, hyperbolic model, load-displacement response. La recherche sur les puits fores en postcoulis s'est principalement concentree sur les pointes en postcoulis. Ici, quatre essais de charge sur le puits en grandeur reelle ont ete effectues pour etudier le comportement et la performance des puits fores tres longs et de grand diametre, avec la pointe et les cotes injectes au coulis, en couches de sable fin tres epaisses. Le mecanisme ameliore des puits fores avec coulis combine est analyse et une approche rationnelle d'analyse de leur reponse de deplacement de charge est presentee. La resistance laterale et la resistance de la base des puits fores avec coulis combine ont ete considerablement renforcees, ce qui a permis d'augmenter considerablement la capacite portante et de controler efficacement le tassement. Sous la charge ultime, >60 % du deplacement de la tete du puits a ete cause par la compression du puits; une proportion relativement faible de la charge a ete supportee par la base du puits. Le puits fore tres long et de grand diametre peut etre traite comme un puits travaillant au frottement. Par ailleurs, l'injection de coulis combine de la pointe et des cotes ne peut pas modifier les caracteristiques de portance. Le modele hyperbolique decrit la relation entre la resistance laterale et le deplacement relatif puits-sol et capture la reponse resistance-deplacement de la base. L'approche proposee est verifiee a l'aide d'un historique de cas, et les comportements de portance d'un puits fore de grand diametre sous une couche de sable fin tres epaisse sont analyses. Ces resultats clarifient les caracteristiques de portance des puits avec coulis combine et peuvent aider a guider la conception des puits en postcoulis. [Traduit par la Redaction] Mots-cles: puits fore tres long et de grand diametre, injection de coulis combine de la pointe et des cotes, methode des cellules d'Osterberg, modele hyperbolique, reponse de deplacement de la charge., Introduction Drilled shafts have been widely employed as the foundations of high-rise buildings, highway bridges, and high-speed railways. As high-rise buildings and large bridges are continuously developed to greater heights [...]

Masses of iron sludge generated from engineering practice of classic Fenton reaction constraints its further promotion. Accelerating the FeIII/FeII cycle may be conducive to reducing the initial ferrous slat dosage and the final iron sludge. Based on the reduction of Pd/MIL-100(Fe)-activated hydrogen, an improved Fenton system named MHACF-MIL-100(Fe) was developed at ambient temperature and pressure. 97.8% of sulfamethazine, the target pollutant in this work, could be degraded in 5 min under the conditions of 20 mM H2O2, 25 μM ferrous chloride, initial pH 3.0, 2 g·L−1 composite catalyst Pd/MIL-100(Fe) and hydrogen gas 60 mL·min−1. Combining density functional theory (DFT) calculation and intermediate detection, the degradation of this antibiotic was inferred to start from the cleavage of N-S bond. The catalytic of Pd/MIL-100(Fe), demonstrated by the removal efficiency of SMT and the catalyst morphology, remained intact after six reaction cycles. The present study provides an insight into the promotion of Fenton reaction. [ABSTRACT FROM AUTHOR]