Interface Shear Box (Large-Scale)
ASTM D 5321 - Standard Test Method for Determining the Coefficient of Soil and Geosynthetic or Geosynthetic and Geosynthetic Friction by the Direct Shear Method.
ASTM D 6243 - Standard Test Method for Determining the Internal and Interface Shear Resistance of Geosynthetic Clay Liner by the Direct Shear Method.
The Large-scale Interface Shear Box is used for evaluating the friction between a geosynthetic and soil, or a geosynthetic and another geosynthetic. It provides a 12 x 12 inch (305 x 305 mm) shear area and works with both consolidated-drained and saturated samples. Optional accessories allow for consolidation testing.
The Large-scale Interface Shear Box has the ability to apply and monitor a wide range of normal and shear loads to provide the data needed for commercial design, research and quality control. The use of a detachable drive system allows a single drive unit to be used with several shear boxes. This efficient use of the drive unit is significant in test situations where soil saturation or sample set-up is a major time factor.
How does it work?
The frictional resistance between geosynthetics, fine grain soils or any combination of soil and geosynthetics may be measured. The tests may be conducted in saturated conditions as the test module box can be filled with water. This enables true simulation of the site conditions. The geosynthetic is sandwiched between the two sample box halves and normal and shear forces are applied to determine the point of failure.
Vertical loading is applied to the sample by compressed air acting on a flexible bladder fitted to the upper box . The load is controlled with a with a precision air regulator.
Data is displayed on four digital readouts with download capabilities.