Effects of Construction of Diaphragm Wall Panels on Adjacent Ground: Field Trial

Common design practice for diaphragm walls is based on the assumption that the wall is “wished-in-place,” which implies that the construction of a diaphragm wall, itself, does not cause any movements or changes in lateral earth and water pressures. However, the construction of a diaphragm wall, itself, can cause ground movements, and changes in lateral earth and pore water pressures that depend on the wall thickness, soil type, and construction techniques. The effects of wall construction may be of particular interest at sites with sensitive structures nearby. This paper presents the performance of a 1.2 m thick, 55.5 m-deep test diaphragm wall panel during construction in a mixed-soil profile with thick layers of soft marine clay. The site was located just next to an existing mass rapid transit station and viaduct. The test wall panel was well-instrumented and was carried out to study the effect of wall construction and other factors that might affect its performance. During the construction of the test wall panel, the effects of trenching of the panel, holding time, variation of slurry pressure, and concreting of the panel on the performance of the wall panel were monitored closely. The aspects of performance evaluated include lateral and vertical soil movements, and changes in piezometric level.