ABSTRACT
It is well known that the shear strength parameters [cohesion (c) and friction angle (ϕ)] are important parameters for evaluating deformation and stability of geotechnical structures, such as slope stability, bearing capacity of foundations, and earth pressure of retaining walls. As far as the reliability analysis of these geotechnical structures is concerned, the shear strength parameters are typically treated as uncertain parameters (Griffiths et al. 2011; Cherubini 2000; Abd Alghaffar and Dymiotis-Wellington 2007). Furthermore, it is widely accepted that c and ϕ are negatively correlated in the literature (e.g., Low 2007; Li et al. 2011; Tang et al. 2012, 2013a). To evaluate the reliability of geotechnical structures exactly, the joint cumulative distribution function (CDF) or probability density function (PDF) of shear strength parameters should be known. It is concluded by the previous studies (e.g., Low 2007; Li et al. 2011; Tang et al. 2012, 2013a) that the negative correlation between cohesion and friction angle has a significant effect on geotechnical reliability and ignoring such a correlation would lead to an overestimate of the probability of failure.
