The analysis of slopes by 3D techniques such as the Limit Equilibrium Method (LEM) has received increased attention in recent years. The increased use has resulted in additional questions surfacing relating to the use of such analysis in consulting practice. Consulting engineers are interested in understanding the potential differences between 2D and 3D analysis as it relates to the modeling of either backward or forward analyses.
Over the past few years since the release of SVSLOPE 3D in 2011, our firm has discussed with many clients about the move from a traditional 2D stability analysis to a more comprehensive 3D analysis. It is rewarding to see the understanding of new analysis capabilities take hold and the first 3D model created. However, we have noticed that there are some typical questions asked by geotechnical engineers when moving to this new type of analysis. There are also mis-understandings related to the application of a 3D analysis in practice. Typical questions include:
“Do I need additional field data?”
“Do I need additional or different laboratory testing?”
“How long does it take to set up a 3D model?”
“Is a 3D model FOS the same as 2D?”
“Is a 2D or a 3D analysis more reliable?”