Selected Topics Regarding Geosynthetic Clay Liners

• Offered for free to Central Ohio Section ASCE Members
• Seating is limited to the first 25 people
• Bring your own lunch

Purpose and Background
Geosynthetic clay liners (GCLs) are very thin layers of bentonite sandwiched between two geotextiles and then needle-punched or stitch-bonded together to form a barrier to liquids and gases. They first appeared in 1986 to absorb leakage through overlying geomembranes in landfill liner systems. Currently, they are being used for both liner and cover systems in myriad environmental, transportation, hydraulic and private development applications. There are approximately twenty manufacturers and the worldwide annual usage is about 150 million square meters. That said, the acceptance and use of GCL's by geotechnical engineers has not progressed nearly as rapidly as it has with other geosynthetic materials like geomembranes, geogrids, etc. Perhaps the main reasons are that compacted clay liners (CCLs) are deeply entrenched in the academic backgrounds of geotechs and also subsequent field experience over the years. This is reflected in current environmental regulations, few of which allow for GCLs to replace or even augment CCLs. This webinar presents the most relevant topics/aspects involving GCLs, including cases of inadequacies in the areas of shear strength and hydraulic conductivity. The webinar also covers the most current GCL testing protocols. In that light, the webinar offers a point-and-counterpoint of GCLs vs. CCLs in both liners and covers. It describes a generic specification with not only suggested limiting test values but also recommendations on quality control and quality assurance.

RSVP to jross@smeinc.com by Friday, February 19, 2016.

Primary Topics of Discussion

• Brief History of GCLs
• Cases of Inadequate Shear Strength
• Shear Strength and Peak vs. Residual Decisions
• Tension Peel Strength
• GCL External Interfaces
• Cases of Inadequate Hydraulic Conductivity
• Flow Through GCL Overlaps
• GCL Panel Separation
• GCLs vs. CCLs in Liners and Covers
• The GRI-GCL3 Specification

Learning Outcomes

• Discover the history and manufacturing of GCLs
• Learn about field cases of inadequate shear strength
• Understand testing and critical details of shear testing
• Discuss field cases of inadequate hydraulic conductivity
• Explore testing and critical details of hydraulic conductivity testing
• Become familiar with point-and-counterpoint of GCLs vs. CCLs in both liners and covers
• Emerging GCL opportunities
• Generic specification for GCLs

Webinar Benefits

• Understanding of GCL details; their strengths and weaknesses
• Appreciate the distinctions of using GCL's as liners versus covers
• Learn about current research and testing of GCLs
• Understand the distinctions between GCLs and CCLs in liner and cover systems
• Learn about new GCL opportunities and a generic specification

Intended Audience

• Geotechnical engineers
• Geosynthetic engineers
• Geoenvironmental engineers and regulators
• Hydraulic and coastal engineers
• Private and public industry planners and designers of containment systems
• Webinar Outline

GCL Overview

• Shear strength issues and testing
• Hydraulic conductivity issues and testing
• GCL's vs. CCL's in liner and cover systems
• Emerging GCL's opportunities
• GCL generic specification

See the ASCE website for more info.

The Central Ohio Section of ASCE sponsors free continuing education webinars as a service to our members. These webinars are produced by ASCE and normally cost $250 or $300 for ASCE members. However, the Central Ohio Section is paying the registration fee and inviting any interested section members to attend for free. Just RSVP by the deadline. Seating is limited, so do not delay.

You can see the complete list of webinars available from ASCE National on their website. If you see one you like, let us know. If you and your company would like to host one, let us know that too. If you open it up to any interested Central Ohio ASCE section members to come, we will pay the registration fee.