Phase2 Article

You've Come A Long Way, Baby! The Many Phases of Phase² 6.0
Phase² began life in 1992 as Phases, a hybrid finite-element/boundary element program for underground excavations in rock. With the third release came a new finite-element engine that currently forms the basis for the latest version. In 1999 a complete rewrite of the user interface was undertaken to move the program to a Windows 95 (Win32) based platform, and the 2001 release of version 5.0 moved Phase² towards a more general geotechnical modeling tool for both rock and soil that included the addition of pore pressures and effective stress for failure computation and new support models. The latest version of Phase² was released in June 2005 and has been well received by our clients. But what does it take to make a great geotechnical program even better? RocNews decided to go straight to the source and asked two members of the Phase² 6.0 development team – Brent Corkum and Thamer Yacoub – to get the lowdown on what makes this new version tick.
Displacement contours in geotextile reinforced ramp with loading
RocNews: *So let’s start at the beginning. What made the team decide it was time for a new version of Phase²?* Thamer: To be honest, Phase² 5.0 was due for an upgrade. It had been several years since we'd revisited the program and we'd been getting requests from our Phase² 5.0 users to enhance the productivity and creativity of the existing software . Brent: Exactly. And not only do we take user requests and recommendations very seriously, we realized we needed to bring the user interface up to current Rocscience usability standards. We wanted to extend the program's application to soil engineering problems such as slope stability, retaining structures, mechanically stabilized earth (MSE) structures, earth dams and groundwater modeling. So you can see we had some work to do!
Groundwater seepage in cofferdam, total head contours (Click image to enlarge)
RocNews: *With all the requests you received, how did you ultimately decide what improvements to make?* Brent: It wasn't easy, that's for sure! But what we finally decided to concentrate on were those features that would be most significant to the end user. For example, we realized that the ability to easily do finite-element slope stability and MSE modeling would be key. Now the integration with our Slide limit equilibrium slope stability package makes finite-element slope stability modeling as easy as reading the Slide data file and pressing the compute button.
Slide embankment model imported into Phase² and automatically meshed (Click image to enlarge)
Thamer: We also felt that adding Cam-clay models and Non-linear (Duncan-Chang) elastic modeling for soil and Generalized Hoek-Brown criteria for rock would be a significant improvement. We also added new support models such as tiebacks, soil nails and geotextiles in order to make it even easier to model and design soil structures.
Tieback bolt properties
Brent: Right. And another improvement we knew users would like was the usability improvements making Phase² 6.0 a faster and more versatile finite-element program. Users of our Slide software know how easy it is to set up a model. Features such as AutoCAD DXF import, spreadsheet import of coordinate tables, tracing over scanned images, and our interactive CAD-based drawing tools make data entry a breeze – no pointless restrictions on geometry entry make learning this program easy as pie!
Context menu available during boundary entry
RocNews: *And the biggest challenge on this project?* Thamer: That's an easy one – the biggest challenge was figuring out how we were going to be able to incorporate all our users' requests as well as the additions we ourselves wanted to include! Brent: You said it! When we sat down to determine the feature list for Phase² 6.0, we realized that adding all the features we wanted in a suitable time frame was going to be a daunting task indeed! Plus a number of the features – such as the Shear Strength Reduction (SSR) slope stability implementation – had a significant research component which made timing the project a challenge. Thamer: Trying to incorporate more functionality while keeping the program as simple and user-friendly as it is was also a challenge, but I think we lived up to it and came out with a better product in the end.
Shear strength reduction (SSR) analysis of geogrid reinforcement embankment (Click image to enlarge)
RocNews: *You mentioned the SSR Method. How is it used in Phase²?* Brent: The SSR method is used here to determine the factor of safety of a slope or MSE structure using the finite-element method. It's a widely accepted method that's been around since the mid 1970's, but hasn't been used extensively in practice because of the lack of a quick, easy and affordable tool. Thamer: We're proud to say that Phase² is currently the only software on the market that does automatic SSR for both linear (Mohr-Coulomb) and nonlinear strength criteria (Generalized Hoek-Brown and power curve). Basically what we've done is take a complex modeling process and simplified it to the point where it's extremely easy to use. Again, customers of our Slide product will know what Brent and I mean when we say that building and analyzing the model is extremely fast and easy, and can be done in under half an hour.
Slide model of slope over bedrock, minimum safety factor = 1.53
Equivalent Phase2 model (see figure above), critical SRF = 1.52
Brent: Slide models are imported, meshed and converted automatically, so in no time at all you can augment your Slide limit equilibrium analysis with a finite-element analysis, thus verifying your choice of a critical failure surface and providing extremely useful information on the deformation and failure modes of your structure. RocNews: *It certainly sounds like you guys had your hands full! Okay, next question: a recent article in RocNews discussed the new soil applications. Can you elaborate on these for us?* Brent: Certainly! When we were developing Phase² 6.0 we really put a lot of effort into extending its application to soil problems. During the design phase, we looked at all the analyses and problems that a geotechnical engineer might have to do and then figured out what we had to add to the upgrade to be able to do these problems more easily.
Modified Cam-Clay input parameters in Define Material Properties dialog (Click image to enlarge)
Thamer: We took a look at the kinds of problems our customers wanted to do, then designed the software to do it. You see, the Cam-Clay models are widely accepted as constitutive relationships that adequately describe the essential mechanics of clay behaviors. The advantage here of the Modified Cam-Clay model lies in its apparent simplicity and its capability to represent the strength and deformation properties of clay realistically. RocNews: *With the amount of versatility this program seems to have, what kinds of projects do you anticipate Phase² 6.0 will typically be used on?* Thamer: I'd say that typically, Phase² 6.0 will be used for tunneling, surface excavation, shoring, staged groundwater analysis and support design. Structures in soil and/or rock can be easily modeled in this program.
Tunnel reinforcement with bolts and shotcrete (Click image to enlarge)
Brent: I agree with Thamer. We've gone out of our way to make this as versatile and flexible a program as possible. RocNews: *Okay, just one last question for you: what advice do you have for users on how to get the most out of this new release?* Brent: The best thing is to go through the tutorials. Phase² 6.0 has an extensive library of tutorials demonstrating how to apply the software to typical kinds of projects. For people thinking about buying the software, these tutorials are available on the Rocscience website. Thamer: Users should also try to take advantage of the new interface features, like the extensive right-click functionality for model creation and editing. Almost all objects include context sensitive right-click menus which make for great short cuts. I'd also suggest checking out the verification manuals. Many new verification examples have been added for SSR slope stability and groundwater analysis. These files are included with the program installation so you can easily explore them on your own. They also give the user a good overview of the wide range of models to which Phase² 6.0 can be applied. RocNews: *This has been very informative! Thanks to you both for your time and this great behind-the-scenes look at Phase² 6.0.* And for those of you interested in learning more about this program, just drop by the Rocscience Website at www.rocscience.com for full details on the software's capabilities, ordering information and how to obtain a free two-week trial version.