Woven Geopipe?

June 1, 2015

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline We hope you can give us contacts for some fabricators who could supply geosynthetic pipe or equal. We want to make woven pipe for water—sizes from 3 to 30 feet and pressures 10 to 100 feet of head. …

Welding on the slope

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline I have a colleague who is insisting that we build a pond’s embankment extension by welding new geomembrane to an old one on the “slight” slope (really somewhere 1:4 ratio). I am arguing that we should do welding …

Suction component to resist uplift?

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline What about a reservoir geomembrane liner over a secondary hot-mix asphalt (HMA) liner with adequate anchorage below the crest (fill embankment) and at the bottom (minimum water depth)? The secondary HMA liner is intended to be “impermeable” and …

Liner root penetration

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline I have a liner/cap that consists of 2 feet of soil, a double-sided 6-ounce geotextile drainage composite, and a 40-mil textured LLDPE. I have a regulatory comment to address: “Will the cover-liner be susceptible to damage through root …

Extrusion welding HDPE liner with LLDPE

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline I have a project where the contractor is insisting that welding a 2mm single-side textured HDPE geomembrane to a concrete structure (HDPE polylock embedded) with LLDPE rods is not a compromise in the quality of the weld and …

Geomembrane (GM) testing

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline We have a project where we need to weld a section of new 1.5mm smooth HDPE geomembrane to an old one installed in 1999. Can you tell me which tests we have to take before we do the …

Cohesion (or adhesion) and friction angle in direct shear tests

April 1, 2009

A technical note regarding interpretation of cohesion (or adhesion) and friction angle in direct shear tests By Richard Thiel Introduction Direct shear testing with geosynthetics is generally performed in accordance with ASTM D5321, Standard Test Method for Determining the Coefficient of Soil to Geosynthetic or Geosynthetic to Geosynthetic Friction by the Direct Shear Method. There …

GCL shrinkage: A possible solution

February 1, 2009

By Richard Thiel and Chris Thiel Introduction A potential industry-wide concern for GCL shrinkage was identified by Thiel and Richardson (2005) at the January 2005 Geo-Frontiers conference in Austin, Texas, based on observed problems at several sites worldwide. All of the known problems were for installations where an exposed geomembrane/GCL composite installation was left unballasted …

Slope stability sensitivities of final covers

August 1, 2008

By Richard Thiel Abstract The geotechnical aspects of final cover system slope stability follow the same principles used for other geotechnical stability problems. What is unique and important to recognize, relative to final cover systems, is their sensitivity to relatively small changes in loading, slope angle, pore pressures, or shear strengths that make them more …

Active LFG control: An unreliable aid to veneer stability

June 1, 2008

By Gregory N. Richardson, Stacey A. Smith, and Pieter K. Scheer Abstract The potential for sliding failure of final covers and piggyback liners in municipal solid waste (MSW) landfills equipped with active landfill gas (LFG) control systems is demonstrated and the need for a contingency passive venting system is presented. Two final cover failures illustrate …