| 摘要 |
A cylindrical, direct shear apparatus and method engage multiple layers of geosynthetic, geotechnical, or both types of materials for evaluating interface friction. Geosynthetic fabrics, geomembranes, naturally occurring materials (soils, rock, gravel, aggregate, other geotechnical materials), and the like maintain frictional contact in many applications. Conventional testing, as per ASTM standard D 5321-92 requires a comparatively modest displacement. Behaviors of geosynthetic membranes and geosynthetic fabrics may change substantially when displaced beyond the dimensions tested under ASTM standards. Accordingly, an apparatus for providing virtually unlimited displacement of layers under "normal" loading for establishing effective "displacement force" in order to establish an "effective coefficient of friction" over a range of displacements. The apparatus and method may rely on a standard, ASTM D-5321 width of sample, but is not restricted to the transverse displacement limitations in an orthogonal direction during the test. The cylindrical, direct shear apparatus and method are consistent with the operational parameters and instrumentation sensitivities required by ASTM D-5321.
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