Planning the release of a 3D slope stability package was the original intent of our development of a limit equilibrium software package. Releasing the 2D aspect of this type of analysis in June of 2008 was a stepping stone. Since we had the team of slope stability experts assembled it seemed the only logical thing to do to proceed in this manner with extending the original 2D product. The background software engineering structure of our other packages was geared for easy 2D or 3D implementations and the graphical tools for creating and manipulating 3D models were already in place. However, planning a large software development project almost never proceeds as planned and numerous changes and accommodations (that are too detailed to be mentioned at this time) were needed along the way.
It is interesting how slope stability analysis has developed over the years. Most slope stability failures are inherently 3D given the dish shaped failure surface. It is fortunate that the practice of geotechnical engineering has been as successful as it has using largely a two-dimensional tool for three-dimensional analysis. It has been noted, however, that more and more analyses are requiring more accurate representation of the slope stability analysis. Therefore it is felt that 3D analysis offers significant advantages in many cases.
Extending the 2D analysis into 3D was not as simple as just turning on a third dimension. Some of the published papers regarding three-dimensional analysis contain errors and oversights and needed further testing and improvement to perform well in three dimensions. The three-dimensional calculations also become significantly more iterative. Therefore a fair amount of work regarding optimization of the speed of three-dimensional calculations had to be performed. In the end of this work paid off as the speed of the three-dimensional analysis is surprisingly fast in SVSlope 3D. Most benchmarks making use of the grid and radius search method ran in terms of seconds. There is therefore little hindrance on analysis speed when moving to a three-dimensional analysis.
A significant part of the design of the 3D package was the user interface. One of the largest hindrances to developing 3D models in the past has been the complexity of inputting a three-dimensional model into the computer. Fortunately SVSlope 3D makes use of the same three-dimensional interface used in our other 3D packages such as SVFlux™ or SVHeat™. The basic concept for creating three-dimensional models is layering surfaces where surfaces can either be krigged from three-dimensional scanner data, entered by the user, or built from a series of interlocking planes. Most recently 3D models can be created based on extrusions of 2D models.
A number of very specific and targeted improvements were made to the SVOffice™ software in order to further simplify 3D model creation. The following specific improvements were made to the graphical description and visualization of a 3D numerical model during the course of development of the SVSlope 3D software package:
It was also the intent of the design team to create a package with exceptional state-of-the-art 3D visualization of the results. This was accomplished with a hybrid approach in which the user can view full three-dimensional representations as well as two-dimensional slices through the critical slip surface. The two-dimensional representations can occur at orientations along the XZ or YZ axes. These two-dimensional representations are identical to the two-dimensional representations already implemented in the two-dimensional SVSlope package. Therefore portions of the three-dimensional visualization are similar to the two-dimensional package. Detailed information on the slice by slice basis can be contoured or presented in the back end (AcuMesh).
In order to develop such a software tool, the technical staff at SoilVision was key in the development of the new package. The core development team assembled to undertake the software development have received graduate degrees by studying under slope stability experts such as Yamagami (dynamic programming research), Morgenstern (Morgenstern-Price method; statistical analysis), and Fredlund (GLE method; dynamic programming research). It was important that each member of the development team has had experience in both geotechnical engineering as well as major software development experience. The core development team included HaiHua Lu, MSc, Tiequn Feng, PhD/PEng, Murray Fredlund, PhD/PEng, Rob Thode, BSc/PEng, Todd Myhre, BSc, and Del Fredlund, PhD/PEng/OC,. The combined group provided significant experience from the field of slope stability analysis.
Proper documentation of the software was a priority. The documentation was divided separately into a user’s manual, a tutorial manual, a verification manual, and a theory manual. The framework established for handling the development of quality documentation for the 2D package was utilized for the 3D package.
Verification of the software package was considered of paramount importance and a great deal of time was extended comparing SVSlope results to published benchmarks. Because the area of three-dimensional slope stability analysis is newer, there are far fewer benchmarks from which to draw. All classic three-dimensional benchmarks were compiled from research literature. The benchmarks were then re-created in the SVSlope 3D software and the answers compared to published results. The benchmarking process was at times tedious as there is no guarantee that published results are necessarily correct. In the end all published benchmarks were matched reasonably well and the results are presented in the SVSlope verification manual. All compiled 2D and 3D benchmarks are solved with each incremental release of our software and checked to ensure models are all solved within required tolerance limits.
We are pleased to introduce you to SVSLOPE 3D, a new standard in 3D slope stability analysis. It is the culmination of years of work, thousands of man-hours and the most extensive review and verification program ever executed by our company. The software has already been successfully applied to world-class projects. Multiple other peer-reviewed consulting applications with the software have also already been performed.
SVSLOPE 3D is intended to provide geotechnical consultants with a comprehensive slope stability package that pays special attention to recent advances in the analysis of natural and man-made slope. We feel that this product implements a balance of leading edge technologies as well as classic slope stability methods and will provide added value to geotechnical engineering consultants. It is fast, easy-to-use, and highly visual. We welcome you to use the results of our hard work at your convenience!