A Grid-Based Methodology for the Assessment of Timedependent Building Damage at Large Scale

Preprint, 2023

Leakage into underground constructions can result in groundwater drawdown and time-dependent settlements in soft clay. In urban areas with spatial variability in geologic stratification, groundwater conditions and soil compressibility, differential settlements may occur, causing damage to buildings. Current methods for damage assessment tend to rely on 1D empirical formulations for settlement prediction, which are not representative for drawdown-induced settlements in heterogeneous environments. In this paper, 2D deformations were first computed using a coupled hydro-mechanical finite element model, simulating the time-dependent pore-pressure reduction in a confined aquifer. An advanced constitutive model was used to account for both creep and consolidation. The results were employed to train a metamodel, which considered spatial variability in stratification, resulting in time-dependent vertical settlements computed as a grid. Based on these results we propose an approach to integrate spatially distributed, grid-type settlement data into building damage assessments at city scale. The approach was applied to 215 buildings in central Gothenburg, Sweden by simulating scenarios of 10 kPa and 40 kPa pore pressure drawdown in the lower (confined) aquifer. The proposed methodology offers an effective way for damage assessments at a large scale, so that further investigations and mitigation measures can be targeted to the buildings at highest risk for damage.