ABSTRACT
Centrifuge modelling has been extensively used in the past to observe the ground response and mechanisms of movement around excavations. Owing to difficulties in performing in-flight excavations, some modellers use a range of cutters to form the main excavation trench and a void for the embedded length of the retaining wall before placing the model on the centrifuge swing. Preparation of an excavation using this technique in very soft clay, where the undrained shear strength is as low as 6 kPa at ground level is challenging as the surrounding soil can easily be disturbed. In addition, as the model reconsolidates in-flight the observed settlements can be considerable. This paper describes a novel process that was developed to prepare a soft soil sample and the apparatus used to model a deep excavation in soft soil. The technique ensured excellent consistency between tests, maintained stability of the excavation during model making and minimised disturbance to the surrounding soil.
