|M.Sc Thesis||Department of Civil and Environmental Engineering|
|Supervisor:||Prof. Emeritus Baker Rafael|
Slope stability calculations are mostly based on the well known linear Mohr-Coulomb strength law. However, experimental results show that for many soils the strength envelope is non linear particularly in the range of small normal stresses. The non linearity of the strength law has a significant effect on the slope stability calculation especially for steep slopes with shallow critical slip surfaces.
The main purposes of this work were to study the effect of the non-linear strength envelopes of non-homogeneous slopes, and to study a number of non-linear strength laws for comparison and eventually to choose the best law representing a data set of experimental results.
The first objective was done by using different slope stability programs (e.g. Slide, Flac, SSopt). To include the non-linear laws in slope stability calculations, a new procedure called “LLA- Local Linear Approximation” was used. This procedure uses the linear Mohr-Coulomb law to examine the effect of non-linear strength laws on slope stability based on the relevant (to the problem) normal stress range.
Choosing the best strength law that fits experimental results was done by using the AIC-Akiake Information Criteria.
This work has showed that the best strength law in most cases is the simple power strength law. And it has showed that LLA method gives good results for non-homogeneous slopes.