A Comparative Study on Decoupled Method for Determination of Permanent Deformation of Slopes

There are quite methods available for estimating earthquake-induced permanent deformation of slopes. Comparisons between the pseudo static and fully-coupled surfaces, conclude that the geometry of the failure mechanism is affected by the dynamic response for wavelength ratios (λ /H) between 1 and 4 where surfaces can be smaller in volume by 20%.The coupled analyses are suggested for these situations because the pseudo static surface assumption is not appropriate. The methods on the basis of pseudo static surface assumption (rigid-block and decoupled) are appropriate and dynamic response has less influence on the failure mechanism geometry, for λ/H greater than 4. In the earliest time a limit-equilibrium pseudo static approach was used for analysis of seismic slope stability and the stability is considered in terms of a simple factor-of-safety. During the 1960s and 1980s, these very basic procedures evolved into more sophisticated deformation-based approaches. To calculate seismically-induced displacements in slopes, we are using one of the available deformation-based analysis method. Such an approach is appropriate as, displacements ultimately govern the serviceability of a slope after an earthquake