Design and Evaluation of a Large Direct Shear Machine for Geosynthetic Clay Liners
- 1 September 1997
- journal article
- other
- Published by ASTM International in Geotechnical Testing Journal
- Vol. 20 (3)
- https://doi.org/10.1520/gtj19970003
Abstract
A large direct shear machine—called the pullout shear machine—for strength testing of geosynthetic clay liners (GCLs) is described. The machine tests rectangular GCL specimens measuring 406 by 1067 mm. The maximum horizontal displacement is 203 mm, which allows for the measurement of both peak and residual shear strengths. The basic design concept for the pullout shear machine is to shear a GCL specimen between a movable pullout plate and a stationary reaction plate, each covered with an aggressive gripping surface. The advantage of this approach is that large specimens can be sheared under high normal stress with negligible friction. Furthermore, the gripping surfaces and the rigidity of the pullout plate enforce uniform shear strain at failure. The paper describes four main components of the machine: (1) the shearing system, (2) the normal stress and vertical displacement system, (3) the specimen hydration system, and (4) the process control and data acquisition system. In addition, a technique is described for the measurement of internal pore pressures within a GCL specimen during hydration and shear. The performance of the pullout shear machine is illustrated using test data for unreinforced and reinforced geotextile-supported GCLs. Finally, the relative merits of the machine are discussed in comparison to the capabilities of other shear testing apparatus currently available.This publication has 8 references indexed in Scilit:
- Landfill cap designs using geosynthetic clay linersPublished by Taylor & Francis Ltd ,2020
- Design and installation of a state-of-the-art landfill liner systemPublished by Taylor & Francis Ltd ,2020
- Discussion of “Shear Strength of Reinforced Geosynthetic Clay Liner” by Patrick J. Fox, John R. Scheithe, and Michael G. RowlandJournal of Geotechnical and Geoenvironmental Engineering, 1997
- Short-Term and Creep Shear Characteristics of a Needlepunched Thermally Locked Geosynthetic Clay LinerPublished by ASTM International ,1997
- Shear Strength of Reinforced Geosynthetic Clay LinerJournal of Geotechnical Engineering, 1996
- Discussion of “Landfill Liner Interface Strengths from Torsional-Ring-Shear Tests” by Timothy D. Stark and Alan R. PoeppelJournal of Geotechnical Engineering, 1995
- Geomembrane Coefficients of Interface FrictionGeosynthetics International, 1995
- Landfill Liner Interface Strengths from Torsional‐Ring‐Shear TestsJournal of Geotechnical Engineering, 1994