ABSTRACT
A combined study of both a centrifuge model test and a full scale model test was carried out to examine the method of detection for the potential threat of failure in trench excavations. A centrifuge model test was first conducted to ascertain the limit depth of trench. A full scale model test was next performed to understand the hazard in the usual trench excavation processes. Several sets of vertical excavations were carried out from the shoulder of a model slope to simulate the trench excavation. In addition, a new method to measure the shear strain, θ in the shallow subsurface was studied to detect an increase of the potential threat of the failure. A clear increases in θ appeared with the progress of excavations in the model. In particular, the relationship between θ and the displacement shows good agreement as a time dependent phenomena. Finally, this study discuses a safety measure of the simplified method by measuring, θ in the shallow section to provide warning to workers at the operations.
