Groundwater And Deep ExcavationsKeynote Address

The presence of groundwater in deep excavations in soil and rock has the potential to profoundly impact both the stability of the excavation, and the impacts that the excavation can have on the areas surrounding the excavation. This paper is intended as a guidance based on the author’s experience to some of the key considerations and pitfalls that designers of deep excavations should take into account when designing deep excavations where groundwater is present. The paper focuses on the influences of Melbourne geology and hydrogeology on the design of deep excavations and provides a brief summary of some of the important groundwater features of the central Melbourne area, but the principles discussed have wider application to projects in similar geology. A series of generalised examples are presented to demonstrate some of the important impacts that groundwater can have on the stability of excavations and structural loads on buried structures, as well as some of the impacts that dewatering activities can have on areas surrounding the excavation.