The performance of soils during excavation and after construction of diaphragm walls

Abstract

This dissertation looks at how soils, particularly cohesive soils behave during and after the construction of diaphragm walls. The latter, particularly utilized abroad is still neglected here in Malta. Diaphragm walling consists of excavation and tremie concreting. These activities differ from normal practices and give rise to many different new skills when bentonite is mixed. Working in the ground is generally more risky than above ground construction. The materials involved are naturally occurring and thus generate more variables than man-made ones. Such variety indicates that a through understanding and analysis of soil conditions is imperative before any construction process is selected. An essential feature that accompanies the construction of diaphragm walls is the analysis of the stability of trenches. Importance is given to the slurry trench method crucial in the determination of particular parameters. All the elements such as unsupported clay slopes, factors of safety, the density of slurry required to oppose the lateral soil pressure, the influence of ground water table and tension cracks will be investigated using the short-term analysis. A complete portrayal of what actually occurs during a slurry trench excavation is provided. The above factors and their consequences are carefully detailed, examined and evaluated in this dissertation through the review of literature and laboratory experiments.