MODELLING OF SURFACE SETTLEMENTS INDUCED BY TUNNEL EXCAVATION USING THE DIFFERENCIAL STRESS RELEASE TECNHNIQUE

After a brief hint to recalling the experimental observations of displacements induced by tunnelling in green-field conditions and to the empirical relationships that are usually used to describe such displacements, this paper describes the differential release technique of the forces that originally act on the excavation boundary and the way in which this technique is applied. This technique is used to numerically reproduce the field of displacements induced by the excavation in green field conditions, as a first step to model the interaction between soil and the existing surface structures. This paper includes then the results of the parametric analysis that made it possible to show how the method can be applied to different geometric configurations and geotechnical situations. These results, which are briefly summarised in diagrams and tables, offer guidance on how to use the method. All the tests were carried out in