The survey phase

Abstract

To perform excavation underground is to disturb natural pre-existing equilibriums. To design such an excavation with respect for environmental equilibriums and with minimum disturbance to stress states (and the deformation response that results) is only possible if one has the fullest possible advance knowledge of the natural state of equilibrium of the ground before excavation begins. Hence the design and therefore the construction of any underground work must be preceded by activity, termed the survey phase, to obtain that knowledge and this is performed by acquiring all possible information on the morphology, structure, tectonics, stratigraphy, hydrogeology, geotechnics, geomechanics and stress states, which characterise the geology of the body of ground in which excavation occurs.