The Geosynthetic Institute (GSI) will sponsor a webinar, “Sand Drains-to-Wick Drains-to-Sand Columns,” on Aug. 14, from 11:30 a.m. to 1 p.m. EDT. Geosynthetic Materials Association (GMA) member companies and their employees receive discounted rates on all GSI webinar and short course registrations.
This webinar begins with Terzaghi’s consolidation work (extended by Barron) leading directly to consolidation of saturated soils using the technique of sand drains. It then describes a case history failure resulting in a $6 million judgment against the design consultant. This project (and greater economic efficiency) led directly to the use of wick drains; also called prefabricated vertical drains or simply PVDs. They are described and illustrated along with concerns of kinking and smear. The requisite research design is numerically illustrated to arrive at a satisfactory factor-of-safety flow value.
This body of work on drainage, however, has a direct relationship on stability of soft soils using the technique of stone columns. Now using columns of sand encased in a geotextile we have a method to both simultaneously drain soft saturated soils and stabilize the site against shear failure as occurred in the case history cited previously. The technology, including its installation, has indeed come full circle.
Participants will learn one-dimensional vertical consolidation (K. Terzaghi) and its extension to radial flow (R. Barron) of soft saturated soils. The classical method of draining such soils by sand drains is illustrated by a case history. Unfortunately, the site failed resulting in major litigation, which was ugly to say the least. However, the introduction and use of wick drains has completely taken over this application. Issues of kinking and smear will be addressed along with FS-design for flow rate and dewatering. These soft soil sites are indeed sensitive to shear failures and by using the classical sand drain installation method now with a geotextile encased sand column we have both drainage and stability.
This webinar will be beneficial to public and private owners of transportation, geotechnical, hydraulic and environmental facilities; consultants and designers in the private sector; regulators and agency personnel at the federal, state and local levels; geosynthetic manufacturers and their representatives; geotechnical and geosynthetic testing organization personnel; contractors and installers of geosynthetic systems; academic and research groups; and others desiring technically related information on this important aspect of our constructed environment.
The webinar’s instructor, Dr. Robert M. Koerner, is professor emeritus of civil engineering at Drexel University, and founder and director emeritus of the Geosynthetic Institute.
Webinars cost $200.00 for GSI and GMA members, and $250.00 for nonmembers. Successful completion of a multiple-choice test after the webinar carries 1.5 professional development hours (PDH).
For more information or to register, visit http://www.geosynthetic-institute.org/webinar.htm.