Chapter 11
Dam Stability Failures
In this chapter we focus on the very common stability failure mode to demonstrate
how it can be evaluated
Failure analysis leading to the risk assessment of dams is a complex process.
It requires modelling the complex relationships between hazards and the potential
response of the dam system. Salmon and Hartford (1995) used Event Tree Analyses
(ETAs). When using an ETA (Viseu and Betamio de Almeida 2009), the initiating
event (e.g., hazard) can be de-convoluted in a logical structure, so that all events,
which can cause a failure or malfunctioning of the system, can be evaluated. Taguchi
(2014) used several trees to evaluate the probability of failure (not the risk) of several
types of TSFs.
In this book, as already stated, we will focus on a very common failure mode,
i.e., instability, as an example, but similar approaches can be develop for any of the
pertinent failure modes.
11.1 Classic Approach
11.1.1 Linking FoS to P f : General Simplified Approach
In a classic stability analysis the Factor of Safety (FoS) is defined as the ratio between
the capacity (C S ) of the slope to withstand failure under the demand (D S , driving
forces) (Eq. 11.1) generated by gravity, water table and, in the case of pseudo-static
analysis, a horizontal acceleration due to a quake.
FoS = C S /D S
(11.1)
© Springer Nature Switzerland AG 2020
F. Oboni and C. Oboni, Tailings Dam Management for the Twenty-First Century,
https://doi.org/10.1007/978-3-030-19447-5_11
153
Dam Stability Failures
In this chapter we focus on the very common stability failure mode to demonstrate
how it can be evaluated
Failure analysis leading to the risk assessment of dams is a complex process.
It requires modelling the complex relationships between hazards and the potential
response of the dam system. Salmon and Hartford (1995) used Event Tree Analyses
(ETAs). When using an ETA (Viseu and Betamio de Almeida 2009), the initiating
event (e.g., hazard) can be de-convoluted in a logical structure, so that all events,
which can cause a failure or malfunctioning of the system, can be evaluated. Taguchi
(2014) used several trees to evaluate the probability of failure (not the risk) of several
types of TSFs.
In this book, as already stated, we will focus on a very common failure mode,
i.e., instability, as an example, but similar approaches can be develop for any of the
pertinent failure modes.
11.1 Classic Approach
11.1.1 Linking FoS to P f : General Simplified Approach
In a classic stability analysis the Factor of Safety (FoS) is defined as the ratio between
the capacity (C S ) of the slope to withstand failure under the demand (D S , driving
forces) (Eq. 11.1) generated by gravity, water table and, in the case of pseudo-static
analysis, a horizontal acceleration due to a quake.
FoS = C S /D S
(11.1)
© Springer Nature Switzerland AG 2020
F. Oboni and C. Oboni, Tailings Dam Management for the Twenty-First Century,
https://doi.org/10.1007/978-3-030-19447-5_11
153