Design of a CCR composite liner system
August 1st, 2021
Q: We are designing a composite liner system for a coal ash landfill. From the bottom-up, the cross section is subgrade soil, geosynthetic clay liner (GCL), geomembrane, composite drainage layer with nonwoven geotextiles on both sides and then ash from coal combustion residuals (CCR). Do you have an opinion on the design, particularly on 3:1 […]
A geotextile filter for an edge drain
August 1st, 2021
Q: I am doing a geotextile filter design for a highway edge drain. All I have from the site is a grain size analysis of the sandy subgrade soil. Can you point me in the right direction? A: First you are going to need to calculate an estimate of hydraulic conductivity for the sandy soil […]
Bringing geomembranes into equilibrium with atmosphere
August 1st, 2021
Q: Some ASTM test methods request that one brings the specimens into equilibrium with the atmosphere prior to the test (some of them determine the conditions: 21±2ºC and 60±10% relative humidity). Considering that we just produce polyethylene geomembranes, and they are not significantly affected by the relative humidity, do you have any suggestions about how […]
Service life of nonwovens
August 1st, 2021
Q: Where can I find literature on the useful service life of nonwoven geosynthetic fabrics installed in soils? A: One of the best references in this regard is from a manufacturer of nonwoven geotextiles. It is: SI Geosolutions (now Propex). (1997). Smart Solutions, Technical Note, SM-404. “The durability of polypropylene nonwoven geotextiles for waste containment […]
Metal leaching from geosynthetics
August 1st, 2021
Q: Geosynthetics are made from polymers that use metal-based catalysts in their formulations. Do geosynthetics have the potential to leach metals into the environment? A: I think the fair answer to this is yes, but the potential risk is very small due to the long-term stability of the polymers used in geosynthetics and the very […]
Koerner Lecture: Geosynthetic-reinforced column-supported embankments: Improving practice with better theory
August 1st, 2021
FIGURE 1 Geosynthetic-reinforced column-supported (GRCS) embankment under construction (Photograph courtesy HUESKER Synthetic GmbH) Editor’s Note : Jie Han, Ph.D., P.E., F.ASCE, is the third recipient of the Dr. Robert M. Koerner Award and Lecture Series. The two past recipients are George R. Koerner, Ph.D., P.E. and CQA, in 2017, and Barry Christopher, Ph.D., P.E., in 2019. […]
Construction of roads in underground mines with 3D geocells
August 1st, 2021
FIGURE 1 An LHD (load, haul, dump) delivering crushed stone to fill in the geocells Access roads are a critical infrastructure component for underground mines. The operational characteristics of these roads directly affect mine efficiency, operating costs and safety. Much of the mine’s operating expenses are due to material transportation, and well-constructed roads help reduce […]
Bluff repair in seismically active zone
August 1st, 2021
Q: I am doing a bluff repair on the West Coast in a seismically active zone. Can you direct me to where I can get some design guidance? A: The following references are excellent in regard to your question. National Concrete Masonry Association. (2009). “Guidelines for the design and analysis of mechanically stabilized earth (MSE) […]
Geosynthetic portable cofferdams for civil construction applications
August 1st, 2021
FIGURE 1 Four-foot (1.2-m) flood control cofferdams in Greece, N.Y. Cofferdams are an enclosure built within or across a body of water to allow the enclosed area to be dewatered. This creates a dry working environment so construction can be carried out properly and safely. Typical cofferdams are welded-steel structures consisting of sheet piles, wales […]
A special issue of Geosynthetics magazine
August 1st, 2021
In this special issue of Geosynthetics magazine, Jie Han, Ph.D., P.E., F.ASCE, of the University of Kansas, the 2021 Dr. Robert M. Koerner Lecturer and Awardee, has written a fascinating article, “Geosynthetic-Reinforced Column-Supported Embankments: Improving Practice with Better Theory,” summarizing the key contents of his Koerner lecture and emphasizing the important point: Improving practice with […]