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Hoffman Estates, United States

Fox P.J.,University of California at San Diego | Thielmann S.S.,University of California at San Diego | Stern A.N.,Geosyntec Consultants | Athanassopoulos C.,CETCO
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2014

An experimental program of large-scale direct shear tests has indicated that shear displacement of a high-density polyethylene (HDPE) geomembrane (GM) over a gravelly compacted clay liner (CCL) under moderate to high normal stress conditions can cause much greater damage to the geomembrane than static pressure alone. Essentially, no damage was observed at low normal stress. The greatest geomembrane damage occurred at high normal stress (1,658 kPa) and yielded an average of 169 holes/m2, with a maximum hole size of 23 Size, angularity, and hardness of the gravel particles are also important factors with regard to potential damage. Geomembrane damage was greatly reduced when a needle-punched geosynthetic clay liner (GCL) was placed between the geomembrane and gravelly CCL, including one test conducted at very high normal stress (4,145 kPa). The findings suggest that gravelly soils should be viewed with caution for the construction of GM/CCL composite liners for landfill bottom liner systems and other moderate- to high-stress applications. If there is a reasonable expectation for GM/CCL interface shear displacement, project-specific direct shear tests should be conducted to determine the potential for shear-induced geomembrane damage. Recommendations are provided for the performance of such tests and for design options when damage mitigation is necessary. © 2014 American Society of Civil Engineers. Source


Jagupilla S.C.,Stevens Institute of Technology | Grubb D.G.,CETCO | Wazne M.,Stevens Institute of Technology
Geotechnical Special Publication | Year: 2012

The immobilization potential of Sb(III) and Sb(V) by freshly crushed steel slag fines (SSF) media was evaluated. The SSF media was characterized as USCS SP type soil with <5% passing the No. 200 (0.075 mm) sieve. Despite its granular nature, the mineralogy and residual lime content make the SSF media quite reactive and there is interest in potentially using SSF media in firing range back stop berms. Accordingly, the SSF media was individually spiked Sb(III) and Sb(V) solutions having target doses equivalent to 100 mg/kg to 10,000 mg/kg to gauge the ability of the SSF media to immobilize antimony, an alloy used in munitions. After 30 days of mellowing, all samples were air-dried and tested for pH, total metal concentrations, toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) leaching performance. © 2012 American Society of Civil Engineers. Source


Jagupilla S.C.,Stevens Institute of Technology | Grubb D.G.,CETCO | Wazne M.,Stevens Institute of Technology
Geotechnical Special Publication | Year: 2012

Batch kinetics and column studies were conducted using freshly crushed steel slag fines (SSF) media to immobilize Se(IV) and Se(VI). The SSF media was characterized as USCS SP type soil with <5% passing the No. 200 (0.075 mm) sieve. Despite its granular nature, the mineralogy and residual lime content of the SSF media make it quite reactive. Accordingly, batch (immobilization) rates of Se by the SSF media were evaluated using aqueous Se(IV) and Se(VI) salt solutions having target doses equivalent to 10,000 mg/kg (500 mg/L equivalent). The percent removal of Se(VI) and Se(VI) by SSF was about 94% and 6%, respectively after 18 hrs mixing time. Column studies were also conducted to evaluate the selenium removal at lower influent concentrations (30 to 40 mg/L), but typically in excess of dissolved Se concentrations observed in the Western US groundwaters and acid mine drainage leachates. © 2012 American Society of Civil Engineers. Source


Smith M.E.,RRD International Corporation | Athanassopoulos C.,CETCO
Geosynthetics | Year: 2013

Waste rock dumps and tailings impoundments are common features at mine sites. Many of these waste disposal facilities contain sulfide-rich minerals that generate acid mine drainage (AMD) when they ox idize in the presence of ox y gen and water. Control of AMD is achiev ed by remov ing one or more of the three essential components in the acid-generating process: sulfides, air, or water. A n AMD prev ention measure with a good history is to properly cap the waste and thereby minimize the infiltration of water and diffusion of air into the sy stem. Source


Fox P.J.,University of California at San Diego | Athanassopoulos C.,CETCO
Geosynthetics | Year: 2013

The final segment of our three-part series on geosynthetic clay liner (GCL) shear strength is devoted to dynamic strength, the strength measured for rapid loading conditions. Static shear strengths have been reported for a wide variety of GCLs and GCL interfaces. A research program has been completed on dynamic internal and interface shear strengths for needle-punched (NP) GCLs and textured geomembranes, as these are common liner materials, particularly in North and South America. The shearing surfaces prevent specimens from slipping and thereby avoid associated progressive failure effects. Monotonic tests consisted of a single shear thrust at a specified displacement rate. Cyclic shear tests consisted of back-and-forth shear motion at a specified frequency and displacement amplitude. Published strength data are suitable only for preliminary design purposes. Final design strengths must always be measured using project-specific tests. Source

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