Design charts for the stability analysis of unsaturated soil slopes
- Authors: Gavin, Kenneth , Xue, Jianfeng
- Date: 2010
- Type: Text , Journal article
- Relation: Geotechnical and Geological Engineering Vol. 28, no. 1 (2010), p. 79-90
- Full Text: false
- Reviewed:
- Description: Simple limit equilibrium analyses can be performed to determine the Factor of Safety (FOS) against slope failure of unsaturated soil slopes. However, many of the input parameters needed for these analyses are highly variable, and the FOS value obtained is critically dependent on assumptions made by the designer. This paper describes a suite of reliability analyses on unsaturated soil slopes performed using an invariant reliability model. The results are presented in design charts from which a designer can choose the FOS value required to ensure a given target reliability index for a slope. The approach ensures that despite the variability of input parameters the slope will have a probability of failure of 2.23% or less.
Deterministic and probabilistic multi-modal analysis of slope stability
- Authors: Reale, Cormac , Xue, Jianfeng , Pan, Zhangming , Gavin, Kenneth
- Date: 2015
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 66, no. (2015), p. 172-179
- Full Text: false
- Reviewed:
- Description: Traditional slope stability analysis involves predicting the location of the critical slip surface for a given slope and computing a safety factor at that location. However, for some slopes with complicated stratigraphy several distinct critical slip surfaces can exist. Furthermore, the global minimum safety factor in some cases can be less important than potential failure zones when rehabilitating or reinforcing a slope. Existing search techniques used in slope stability analysis cannot find all areas of concern, but instead converge exclusively on the critical slip surface. This paper therefore proposes the use of a holistic multi modal optimisation technique which is able to locate and converge to multiple failure modes simultaneously. The search technique has been demonstrated on a number of benchmark examples using both deterministic and probabilistic analysis to find all possible failure mechanisms, and their respective factors of safety and reliability indices. The results from both the deterministic and probabilistic models show that the search technique is effective in locating the known critical slip surface while also establishing the locations of any other distinct critical slip surfaces within the slope. The approach is of particular relevance for investigating the stability of large slopes with complicated stratigraphy, as these slopes are likely to contain multiple failure mechanisms. © 2015 Elsevier Ltd.