| Autor: |
L David Suits, TC Sheahan, PJ Fox, CJ Nye, TC Morrison, JG Hunter, JT Olsta |
| Rok vydání: |
2006 |
| Předmět: |
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| Zdroj: |
Geotechnical Testing Journal. 29:100183 |
| ISSN: |
0149-6115 |
| DOI: |
10.1520/gtj100183 |
| Popis: |
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. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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