Large Dynamic Direct Shear Machine for Geosynthetic Clay Liners

    Volume 29, Issue 5 (September 2006)

    ISSN: 0149-6115

    CODEN: GTJOAD

    Page Count: 10


    Fox, PJ
    Professor, Ohio State University, Columbus, OH

    Nye, CJ
    Graduate Research Assistant, Ohio State University, Columbus, OH

    Morrison, TC
    Staff Engineer, Barr & Prevost, Columbus, OH

    Hunter, JG
    Civil Engineering Shop Manager, Ohio State University, Columbus, Ohio

    Olsta, JT
    Technical Manager, CETCO, Arlington Heights, IL

    (Received 26 December 2005; accepted 22 May 2006)

    Abstract

    A large direct shear machina for static and dynamic shear strength testing of geosynthetic clay liners (GCLs) and GCL liner systems is described. The machine tests rectangular GCL specimens measuring 305 × 1067 mm and has a maximum shear displacement of 254 mm, which is sufficiently large to allow for the measurement of residual or near-residual shear strengths in most cases. The basic design concept for the device is to shear a GCL specimen between a bidirectional pullout plate and a stationary reaction plate, each covered with an aggressive gripping surface. The pullout plate is driven by a computer-controlled hydraulic actuator. The maximum normal stress is 2000 kPa, the maximum shear stress is 750 kPa, and the shearing system is capable of imposing general stress-controlled or displacement-controlled dynamic loading to a test specimen. The actuator has a maximum frequency of 4 Hz for sinusoidal loading with a displacement amplitude of 25 mm. The maximum displacement rate for burst loading (i.e., single thrust) at zero force is 1 m/s. The paper describes four main components of the machine: (1) the shearing system; (2) the normal stress and vertical displacement measurement system; (3) the specimen hydration system; and (4) the process control and data acquisition system. The performance of the machine is illustrated using displacement-controlled test data for the static and cyclic internal shear strength of a hydrated needle-punched GCL.


    Paper ID: GTJ100183

    DOI: 10.1520/GTJ100183

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    Author
    Title Large Dynamic Direct Shear Machine for Geosynthetic Clay Liners
    Symposium , 0000-00-00
    Committee D18