Risk Identification and Second-Generation Eurocode 7 Screening of Hydraulic Failure Mechanisms During Retention Tank Construction Adjacent to a Flood Embankment: A Case Study

The realisation of construction objects in the immediate vicinity of flood embankments is among the most demanding engineering processes. All earthworks, drainage, and structural works carried out near the embankments can affect the stability of slopes, filtration conditions, changes in groundwater levels, and local ground loosening. For this reason, it is essential to apply appropriate design, execution, and monitoring methods based on reliable geotechnical reconnaissance and proper implementation procedures. The article presents an analysis of the process of constructing a retention reservoir located near a flood embankment. Particular attention was paid to the impact of executing deep excavations secured with a system of retaining walls on the existing hydrotechnical structure. Based on the analyses conducted, the process of implementing the entire construction project was assessed, considering the potential for failures during and after the investment. A block diagram of the potential construction failure mechanism during the realisation of the retention reservoir near the flood embankment was also proposed. The retrospective EC7-II HYD screening gave ΛHYD = 2.84–3.47% for the Sk/W′k formulation, 58.44–71.42% for the u/σv formulation, and 2.89–3.53% for the Δu/σ′v formulation under VC2(a). Under VC2(b), the corresponding values were 2.69%, 55.31%, and 2.74%. The governing value was ΛHYD = 71.42%, below the 100% worksheet acceptance criterion.