This first day of ER2010 was full of some excellent technical sessions. As you might expect from a conference that occurs once every 20 years, there is a strong theme of looking back at what some of the technical innovations have been in the earth retention field over the last 20 years, and also what some of the future trends are going to be.
So after the morning started with the usual welcomes from the ER2010 committee chair and others from the Geo-Institute and even the ASCE Seattle Geotechnical Group, here are a scattering of some of the interesting points and themes from the various presentations, at least from my perspective. They are not in any particular order.
- Adaptive management of shoring systems will be used more and more. This involves using automated systems for monitoring the structures to iteratively update the numerical models to match the measured displacements and deflections and then predict deflections at future excavation stages.
- Numerical analysis was stressed in several presentations, particularly when trying to determine deformations away from the structure or the affects on existing structures. The trick is to get the initial conditions modeled correctly.
- We will continue to see the use of hybrid support systems employed to solve earth retention projects.
- Sustainability will be a continuing trend, so what does that mean for walls? Possibly non-select backfill, looking at life cycle costs and carbon footprints of various components of the walls, and increased use of literal green structures (as in vegetated RSS)
- Continued development and implementation of LRFD
- Possible use of split zone or 2 zones of backfill in MSE walls
- Continued improvement of design procedures for RSS structures, particularly reliability based design
- A number of cautionary tales or advice regarding careful applications of new technologies and software
- From two presenters (Ryan Berg and Bob Bachus), they indicated that an estimated 5% of MSE walls, particularly segmental retaining walls fail within the first two years! All of the published case studies on these failures are from private developments. Typically these walls are in the 12-36’ height range.