High Capacity Direct Shear Machines measure the total resistance of large, 12in (305mm) square soil or soil/geosynthetic specimens to horizontal shear forces. The specimens are mounted in a two-piece shear box assembly, divided in half horizontally. The bottom half is held securely in place and a vertical confining force is applied. Horizontal force is then directed against the upper half of the box to shear the specimen.
Loads are applied through pistons driven by a stepper motor and gear box system. Confining loads are applied with smaller diameter pistons for greater accuracy and sensitivity of lighter loads, up to 4.4kN (1,000lbf) of force. One or two larger pistons generate loads up to 45kN (10,000lbf), or 90kN (20,000lbf) depending on model selected. Horizontal shear rate from 0.0508—5.08mm (0.002—0.2in) per minute is easily set with digital thumbwheels on the control panel. Limit switches control the home position and limit total horizontal displacement to 102mm (4in). Vertical loading is controlled through a precision regulator, using the included calibration chart to set the required pressure. Loads are displayed to two decimal places on the digital readout and are accurate to ±0.25%. Consolidation and shear displacement are measured by Linear Variable Displacement Transducers. Shear load is measured from a load cell attached to the water chamber. The four-channel readout displays all these values while directing data in ASCII format through the RS 232 serial port to the user’s PC. The included software imports data onto spreadsheets such as Excel® for analysis and reporting. Displayed values on the readout can be viewed at any time.
Loading and unloading the specimen and shear ring assembly to and from the water chamber is simplified using the included Compaction Table. Pulling the loaded shear rings onto the convenient table rollers allows the entire assembly to slide easily in and out of the chamber. Sample compaction, geotextile placement, and specimen preparation can be performed on the table, before placing the assembly directly into the water chamber with little effort.
HM-384 and HM-385 High Capacity Direct Shear Machines can apply maximum piston loads of 45kN (10,000lbf), and 90kN (20,000lbf) respectively and operate at 110V/60Hz. F models operate at 220-240V/50Hz. These units are ruggedly designed for harsh lab environments, with powder-coated steel parts and hard-coat anodized aluminum components that resist corrosion. Casters on the machine and Compaction Table make for easy portability in the lab. Compaction Table, and top and bottom Shear Rings are included. Top ring is 12x12x4in (305x305x102mm), and bottom ring is 12x16x4in (305x406x102mm). Data cable is also included. A 120psi (827kPa) source of clean, dry, compressed air is required for operation. Inquire for customization options for specimen sizes and operating options.
- Can generate loads of up to 45 or 90kN (10,000 or 20,000lbf)
- Tests large soil or soil/geosynthetic samples up to 12in (305mm) square
- Precision regulators control loading and displacement
- Rugged design is well-suited to withstand harsh lab environments
- Anodized aluminum components resist corrosion
- Digital readout
- Compaction table with casters provides easy mobility and is also used for sample preparation
- High Capacity Geosynthetic Direct Shear Machine (45kN, 110V/60Hz or 45kN, 220-240V/50Hz), or
High Capacity Geosynthetic Direct Shear Machine (90kN, 110V/60Hz or 90kN, 220-240V/50Hz)
- Compaction Table
- Water Chamber
- Linear Variable Displacement Transducers
- Top and Bottom Shear Rings
- Software and Data Cable
- Calibration Chart