Numerical analysis of mitigation measures to reduce the pore water pressure beneath a raft foundation during real river floods

Resumen

Building structures in areas subjected to extreme conditions, such as river floods, is highly dependent on the ability of the raft foundation to resist significant changes in pore water pressure (PWP). Such changes, caused by rising water tables and soil saturation, can compromise structural integrity by inducing displacements and failures at the raft foundation. In this context, numerical models are an ideal tool for analyzing and predicting the PWP response that acts beneath the raft foundation during a river flood event. This work explores how numerical models can simulate flooding scenarios and assess the effectiveness of different mitigation measures to reduce PWP mobilization beneath the raft foundation, offering engineers valuable risk reduction strategies and efficient solutions. To do that, numerical models based on the Finite Difference Method are developed, incorporating real river floods associated with various river regimes, such as nivo-pluvial, nival, pluvio-nival, and mixed. Furthermore, this research analyzes the response of different mitigation measures, including levees/floodwalls, waterproof diaphragm walls, and drains, to reduce the PWP mobilization beneath the raft foundation. Results demonstrate that the numerical models developed herein effectively simulate the temporal variation of PWP beneath a raft foundation during real river floods. Also, results suggest that either combining mitigation measures, such as levees/floodwalls with waterproof diaphragm walls, or using drains can significantly reduce the PWP mobilized beneath the raft foundation for all the river regimes considered. Additionally, the findings of this research suggest that levees/floodwalls are particularly more effective in mitigating PWP mobilization during short-duration flooding compared to longer-duration events.