Abstract
This paper addresses the issue of probabilistic and semi-probabilistic modelling of soil slopes. A slope made of cohesive-frictional soil of specific geometry was analysed as an example. Results were calculated for two methods using the Z-Soil finite element software. It has been assumed that the probability distributions of strength parameters, cohesion and internal friction angle are normal distributions with average values and coefficient of variation = 0.2. Random finite element method (RFEM) has been used for probabilistic modelling. Random fields of cohesion and internal friction angle have been generated using the Fourier series method (FSM). Monte Carlo simulation has been used to calculate the statistics of the slope factor of safety in order to determine the probability of failure. Moreover, assumed parameter distributions allowed to determine safe characteristic values used in the semi-probabilistic partial factors method. Both approaches have been compared in the article.
Highlights
Slopes are the most basic and common elements of geotechnical structures
The results are presented in section 5For the semi-probabilistic method only a single calculation for design values of parameters and loads obtained from partial factors described in Table 1 was performed
Based on the calculations presented above, the application of the semi-probabilistic method with partial factors is conservative and leads to providing wider margin of safety. It does not enable precise determination of the safety of a structure from the probabilistic perspective. It uses factors based on general experience that do not necessarily reflect actual conditions of a given structure
Summary
Slopes are the most basic and common elements of geotechnical structures. These methods allowed to determine the critical slip line (it was assumed that the failure occurs on the line with the lowest safety factor). The method was proposed in the pioneer papers in the 1990s and quickly became applied in the slope analysis process [3] They are widely used (rather rarely in practical engineering) for purposes such as determining safety of shallow foundations [4], supported excavation [5] or pile foundation [6]
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