Soil-Building Interaction and Risk Assessment of Existing Structures During Mechanized Tunneling

During the planning phase of tunneling projects, in particular in urban areas, it is crucial to assess the likely extent of structural damage caused by the tunnel construction in close vicinity to existing surface structures. Tunneling inevitably causes ground movements which in turn may have an impact on deformations and stresses of the above-ground structures. For this reason, a reliable estimate of the soil-structure interactions due to tunnelling-induced settlements is essential. In this contribution, various approaches that differ in precision and complexity are employed to predict the magnitude of expected settlements and the vulnerability of structures with regard to tunneling induced damage. In addition, a three-step damage assessment concept adjustable to the necessary level of detail is suggested. Firstly, ground movements are predicted using analytical or numerical approaches. Secondly, the above-ground structures are idealized by means of surrogate beam-, slab- or 3D-models. Finally, structural damage is assessed according to the computed strain pattern or the tilt of the building. This method enables the evaluation of the potential damage to above ground structures associated with planned tunnel alignment. When developing 3D numerical models, the main focus will be to ensure that the building and the soil-structure interactions are represented with an appropriate level of detail. To this end, this paper aims to provide recommendations for a sufficient level of detail (LOD) of surface structures for the assessment of tunneling induced damage in computational simulations in mechanized tunneling.