Abstract Description: Dams play a critical role in water supply, flood control, energy generation, and infrastructure resilience. However, many existing dams, particularly in California, face significant risks due to aging structures, evolving environmental conditions, and outdated design methodologies. These dams pose a danger to downstream populations demanding greater attention to investment in measures to help reduce risks to public safety and economic assets. Traditional deterministic methods for dam stability assessments rely on static factors of safety (FS), often leading to either overly conservative or underestimated designs. In this approach, engineers input known material properties, loads, and the dam's geometry into a single FS, which is then compared to reference values to evaluate the dam's stability. While effective for expedited analyses, this method overlooks uncertainties, potentially leading to overly conservative designs or, conversely, underestimating critical safety considerations. Probabilistic methods provide a more comprehensive foundation for risk evaluation by quantifying the likelihood of not reaching a target performance objective rather than relying on a single safety factor threshold.
This study focuses on analyzing the resiliency of a 326-foot Hardfill dam, under various loads (usual, unusual, and extreme) using a probabilistic analysis. The study integrates semi-probabilistic sensitivity analysis using Tornado Diagrams (TD) to identify critical parameters influencing stability, while providing a visual tool for practicing engineers. Additionally, the research employs CADAM3D for stability analysis and MATLAB for probabilistic analysis, allowing for a comparative assessment between traditional and probabilistic design approaches. This analysis involves a multi-linear regression approach to derive a straightforward equation for the estimation of the factor of safety, which includes parameters identified using the TD. This equation will expedite the implementation of probabilistic analysis and subsequent estimation of the probability of not reaching a target FS as prescribed by national and international guidelines. The proposed procedure is more robust, computationally efficient, and more easily interpretable than conventional methods while accounting for uncertainties in the analysis. This study will allow professionals in the dam industry and dam owners to expedite the safety assessment of similar dams and to identify the parameter uncertainties affecting the dam response the most so that economic resources can be invested in the exhaustive study of these parameters.
Learning Objectives:
Understand the Limitations of Traditional Deterministic Approaches.
Apply Probabilistic and Sensitivity Analysis for Dam Stability.
Compare Computational Tools and Develop Efficient Safety Assessment Approaches.
