Distributed temperature sensing (DTS) can be used to monitor the production process of diaphragm walls. DTS is able to differentiate between already present or fresh bentonite suspensions during refreshing of the bentonite slurry in the trench. During concrete casting, DTS is able to differentiate between the bentonite suspension and concrete. As a result, the continuity of the casting process and the arrival of good grade concrete at crucial locations in the trench can be monitored. Tests conducted on laboratory models provided reference information for interpretation of field data. Field experiences have shown the benefits of DTS tests and the predictive value of the reference measurements. Results are compared with crosshole sonic logging measurements at the same location.Key words: distributed temperature sensing (DTS), diaphragm wall, joint, quality control.Résumé : Des capteurs de température distribués (CTD) peuvent être utilisés pour surveiller le processus de production de parois moulées. CTD est capable de faire la différence entre des suspensions de bentonite déjà présentes et des nouvelles lors de l'actualisation de la suspension de bentonite dans la tranchée est en course. Au cours de la coulée du béton, CTD est capable de faire la différence entre la suspension de bentonite et de béton. En conséquence, la continuité du processus de coulée et l'arrivée de béton de bonne qualité à des endroits cruciaux dans la tranchée peuvent être surveillés. Les essais effectués sur des modèles de laboratoire ont fourni des informations de référence pour l'interprétation des données sur le terrain. Des expériences de terrain ont montré les avantages des essais CTD et la valeur prédictive des mesures de référence. Les résultats sont comparés avec les mesures d'auscultation sonique au même endroit.Mots-clés : capteurs de température distribués (CTD), paroi moulée, joint, contrôle de qualité.
Quality control of diaphragm walls prior to excavation is often difficult. One technique that can be used to detect anomalies in diaphragm walls involves electrical resistance. Electrical resistance measurements across a diaphragm wall can (within a strict framework) be used to verify the presence of leaks in diaphragm walls as a supplement to crosshole sonic logging. From measurements around a test wall conducted in this study, it is concluded that the detectability of anomalies with electrical resistance decreases exponentially with the increasing distance between the measurement electrodes and the wall. Electrical resistance setups with two and four electrodes have been compared. For usable results, a four‐electrode setup must be used in which the potential electrodes need to be placed very close to the wall (less than 0.2 m away). Based upon the test experience, a field setup for verification of a building pit consisting of diaphragm walls is suggested, as well as a setup for determining the quality of the concrete covering the rebar in quay walls constructed with diaphragm walls.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.