Numerical and physical modelling of pore pressure relief drains in homogeneous embankment dams

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The failure of embankments due to seepage and other water-related issues is often underestimated. Pore water pressure buildup in embankments can lead to stability issues or failure of civil infrastructure. This study explores the efficacy of pore pressure relief drains to alleviate excess pore pressure within embankments. Here, silica sand embankment dam models were constructed by means of a drainage and seepage tank to visualize seepage. Numerical simulations, based on the geometries of the physical models, were conducted to mimic and further study the behaviour of homogeneous embankments with different drainage systems. Geotechnical experiments were performed on the material used for physical modelling, and finite element analysis tool (SEEP/W) was used to model the embankment behaviour. The findings showed that strategically placed pore pressure relief drains can effectively reduce excess pore pressure and significantly lower the phreatic surface, thereby improving the stability of the downstream slope. Physical model tests demonstrated significant reductions in pore pressure for drainage types fitted with pore pressure relief drains, this was also confirmed by numerical simulations. Drain location, geometry, and material properties were shown to be crucial factors in designing efficient drainage systems. This work contributes to the stability of embankment structures, particularly in regions with high water tables or heavy rainfall. The combination of physical and numerical modelling improves the understanding of optimal drainage system design. Carefully designed pore pressure relief drain systems can significantly reduce excess pore pressure in homogeneous embankments, enhancing the stability of the downstream slope.

Keywords: Pore pressure relief drains, seepage, physical modelling, numerical simulation.

5th European Conference on Physical Modelling in Geotechnics (ECPMG2024)

Geotechnical infrastructure