Diaphragm walls are often used for permanent retaining walls and shafts; they are particularly suitable for deep projects under high water head. The work sequence of diaphragm walls leads to different adjoining panels. In this way, junctions between diaphragm wall panels are key points, whether it be for formwork, guidance or waterproofing. This hereby document concerns the watertightness aspect and first provides positive and negative backgrounds of several junction types (stop end tubes, double or triple blade system, addition of pipe for aquareactive resin injection, watertight seals, milling) depending on the excavation tools’ type (hydrofraise, hydraulic or mechanic grabs). This paper also lists the different junctions nowadays used for deep excavations, and gives a compendium of good practices, based on recent experience. Finally, it deals with the subject of the joint depth compared to the panel depth, and ends with the special case of diaphragm walls carried out under low clearance.
Subjects: diaphragm wall, panel, joint, watertightness, deep excavation, feedback, good practice
Author: Paul Vidil, Deputy Design Manager
Publisher: DFI, EFFC