Comparison between deterministic and probabilistic stability analysis, Featuring a consequent Risk Analysis
QUEIROZ ISABELA1
1 WALM ENGENHARIA E TECNOLOGIA AMBIENTAL
Resumo
The slope stability analyzes are mostly performed by deterministic methods and evaluated by means of a single factor of safety. Although it is known that the geotechnical parameters may have widely dispersed, these analyzes they are considered fixed and known. The probabilistic methods, in turn, incorporate the variability of input key parameters (random variables), resulting in a range of safety factor values, thus allowing determination of the probability of failure, which is an essential parameter in the calculation the risk (probability multiplied by the result of the event). Among the probabilistic methods, there are three commonly used among geotechnical: FOSM (First Order and Second Moment) Estimated points (Rosenblueth) and Monte Carlo. The Monte Carlo method it is an iterative procedure that includes: the estimated probability distributions for each of the input parameters considered as variables; generating random values for each parameter; calculating the values of the forces acting check-resistant and resistant to forces that are higher active; repetition of process N times, and then determining the likelihood of rupture (Willie & Mah, 2004). The FOSM method (First Order and Second Moment) uses the first terms of a Taylor series expansion of the performance function (ie safety factor) to estimate the expected value (mean) and variance performance function. It is called a second time because the variance is a form of second phase, being the result of higher order statistics used in the analysis (Baecher & Christian, 2003). The method of estimation points or Rosenblueth method for the case of n correlated variables needs 2 raised an estimated value for each combination of particular points (plus standard deviation and mean average ± SD). Upon completion of the combination of particular points, the probabilistic procedure is initiated by means of deterministic calculations for this second group of an elevated values. Thus, for each new step of the probabilistic process, deterministic calculations are fue
Palavras-chave: SLOPE STABILITY; PROBABILISTIC ANALYSIS; RISK ASSESSMENT