In November, Solmax provided a technical webinar presentation on an important question for geomembranes: Does asperity height or asperity concentration matter more for increasing interface shear resistance along a geomembrane surface?
The presentation is now available for open viewing via the company’s YouTube Channel. More technical presentation videos are available in the Solmax Video Library, part of the company’s technical library on its revamped website.
ASPERITY CONCENTRATION & HEIGHT
The objective of texturing is to prevent a geomembrane surface from being a critical slip plane that may induce, contribute to, or make worse potential sliding of materials. As a slope angle increases, higher interface shear resistance may be required along the geomembrane interface to prevent contact materials from sliding.
Achieving higher interface shear resistance along a geomembrane surface is sometimes associated with increasing the asperity height from texturing; but, some studies (e.g. Blond and Elie, 2006) have shown that higher asperity heights may not always result in higher interface shear resistance. Asperity height may only matter up to 20 to 25 mils, beyond which no further gains may be achieved in interface shear resistance.
So, if asperity height has a limit for increasing interface shear resistance, how else can interface shear resistance be increased with textured geomembranes? Will increasing the concentration of asperity and not the height help?
Solmax’s Technical Manager Doyin Adesokan, B.Eng., MSc. leads the discussion. She provides a review of Blond and Elie’s findings for asperity height vs. interface shear resistance and evaluates the contribution of asperity concentration to interface shear resistance relative to asperity height.
The presentation reveals some interesting findings, including on the impact of micro-texturing at an asperity of just 17 mils and the remarkable peak friction and adhesion characteristics this structure has provided in contact with geotextiles.
Also in favor of asperity concentration, the tighter density of texturing will distribute the stress on the geomembrane surface significantly more than on a less dense asperity pattern (which we would expect to find on a textured that is focused on asperity height). Asperity concentration, then, helps manage the threat of stress on a geomembrane, as a geomembrane is not properly a material that should be designed to hold a geotechnical load.
OTHER SOLMAX TECHNICAL WEBINARS
The asperity height vs. asperity concentration technical webinar continues the company’s run of high-quality webinar offerings on important geomembrane design and performance topics. Earlier this year, for example, it presented a session on geomembrane wrinkle management.
Other high profile webinars from the company include Enhancing Quality Assurance with Conductive Geomembranes and Flat Die and Blown Film Geomembranes.
Find educational videos about geomembranes, check out Solmax’s unique drop-in specification tool, find project references, and more at www.solmax.com.1