Geotextiles are frequently used for subgrade improvement under roadways. Caltrans has released a document titled "Guide for Designing Subgrade Enhancing Geotextiles". This 18-page document covers what situations can be improved using geotextiles and includes a flowchart for guidance on when to apply them and for what purposes. From Geosynthetics magazine. (Image by Caltrans)
The site for the new Harrison County Hospital, approximately 25-miles west of Louisville, Kentucky had 15 sinkholes formed by limestone dissolution, a geomorphologic process referred to as Karst topography. There were a number of geotechnical engineering and geological engineering challenges associated with the characterization, excavation, backfilling, foundation engineering and other mitigation measures as described by Peggy Hagerty Duffy, P.E. in her article entitled “Karst and Complications” in the August 2008 issue of Civil Engineering Magazine (Duffy, 2008b).
Mitigation measures for the sinkholes included use of graded filters with geotextiles, careful inspection of rock socket foundations along with pilot holes and careful geotechnical inspection throughout the construction process. One particularly interesting aspect of the project is that several of the sinkholes were used as drainage facilities to receive surface water runoff. Read on for a summary of this interesting article. (Photo of sinkhole in Karst Topography being used as a drainage feature, from Duffy (2008b), Civil Engineering Magazine)
Gundle/SLT Environmental, Inc. (GSE) is a manufacturer and marketer of geosynthetic lining products and services in the following markets: agriculture, aquaculture, canals, civil, golf courses, mining, power, sportsfields, stormwater retention, waste containment, wastewater, and other industrial applications. They have recently released a series of product videos on YouTube. But you don’t have to search for them yourself, you can watch them right here on GeoPrac, just read on! Thanks to Geosynthetica.net for the heads up.
The Countywide Recycling & Disposal Facilities in Stark County, Ohio have a new round of problems. There has been much debate over an underground fire reportedly caused by the disposal of aluminum dross waste, a byproduct of aluminum production, dumped between 1993 and 2001. The site has long received complaints for odors and for a long time denied that there was a fire. They have also had problems with slope stability, including a failure of a portion of the south slope in 2006, possibly a result of the destabilizing effect of the fire. Early this year the Ohio EPA cited the facility for violating 8 environmental regulations after waste was found to have migrated outside the permited waste area.
Their latest problems involve a tear or leak of a geosynthetic lining that caps the facility to control gas and odors from the underground fires and regular landfill gas. The leak resulted in 500 to 5,000 gallons of leachate spilling into a sediment pond. The material fortunately did not leave the site and was pumped out of the pond and transfered to a treatment plant where their leachate usually goes. The landfill, one of the largest in Ohio, handles about 6,000 tons of trash a day, including about half of Summit County’s residential garbage.