Images below courtesy of Controls Testing Equipment Ltd.

300mm Large Scale Shear Box

Item UKAS Description Unit

The system comprises two modules:

  • The drive unit is mounted on a movable, wheeled frame with a handle.
  • The shear box comprises a removable upper half and a lower half which is provided with four legs and is stationary

The frictional resistance between geotextiles, fine gram soils or any combination of soil and geotextiles 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 fabric is sandwiched between the two sample box halves, normal and shear forces are applied to determine the point of failure.

Vertical loading is applied to the sample with a precision regulator and flexible, compressed air filled, diaphram, fitted to the upper box. Alternatively, the shear box can be supplied with an optional rigid platen system The horizontal load is regulated by the DC servo motor control system.

This is made from high quality materials for reliability and ease of operation. It may be upgraded if there is future need for the application of higher loads. Major components are black, hard-coat, anodized aluminum or steel, zinc plated

The GSTL Large Scale Direct 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.

This Model provides a 12 x 12 in (305 x 305 cm) shear zone for determining the interface frictional characteristics of individual geotextile components or remolded soil interacting with a geotextile.

  • A break-away box and drive system for enhanced efficiency
  • A stainless steel tank for submerged sample testing to emulate field conditions
  • The normal load is applied with a flexible bladder or optional air hydraulic cylinder attached to a rigid platen
  • Linear bearings keep horizontal movement friction to a minimum
  • Digital readouts with RS 485/232 output for measuring load, displacement, settlement and pressure
  • Pressure Transducer provided with a quick connect allows use with both a normal and fixed platen

Schematic Geomembrane and Soil