The shear Vane testing is used to determine the total shear resistance of normally cohesive, un-drained soils (especially soft clays) by fast shearing and is mostly useful for soils with low shear strength.

The motorized lab vane was developed and designed according to scientific and research insights and requirements so that undisturbed soil samples (e.g., core cutters) as well as treated samples (e.g., Proctor samples)or artificial mixtures can be tested for practical applications as well as for research purposes.

The test is relatively easy to set up, quick, and provides an economical way of soil shear strength estimation and due to the variable sample container attachment and the height-adjustable vertical cross bar, the shape and size of sample containers which can be used are virtually unrestricted.

We manufacture two models for laboratory Vane shear test which this model is motorized version which gives Digital measurement of shear resistance (torque) using a digital transducer and LC-display with continuous or value storage, and we also manufacture another version which is fully automatic and comes with data acquisition system and software.

The working principle of the laboratory vane shear test consist of pressing a vane (four bladed type)into the soil (undisturbed tube sample or remolded sample) and rotating the vane with a constant rate to shear the cylindrical surface. The torque required for this purpose is measured and then the Undrained Shear Strength (Su) is calculated by a formula by dividing the applied Torque (T) by a constant (K). The K directly depends on the dimension/height of the chosen vane.

The torque is measured by a calibrated torque transducer which is implemented inside the device and attached directly to Vane. This test is a cheaper option compared to the other methods of testing shear strength of clay such as triaxial shear test or direct shear test. 

System Geography

① Hand knob for adjusting the vertical cross bar

② Digital display

③ Front panel including of power indicator, potentiometer, power switch

④ Vane

⑤ Measuring output

⑥ Clamping device for holding sample containers

⑦ Stiff base plate

Digital Display And Switch Labels

• Displayer :The displayer shows the important values during the test and has a green backlighting to ensure readability even in adverse lighting conditions.

• Power indicator:The power indicator is illuminated while the drive is operating.

• Power Switch:Use the power switch to start and stop the device.

• Speed Range Switch:There is a possibility to select one of 3 speed ranges with the speed range switch. The switch in positionx0.1 results in a rotating speed of 0° – 10° per minute.With the switch in the x1 position, the rotating speedis between 10° – 100° per minute. When the switch is in the x10 position, a rotating speed of 100°-1,000°per minute has been selected. 

• Potentiometer:Use the potentiometer for fine adjustment of the selected rotating speed range.

• Peak Value storage Switch:The switch has two selectable operating modes. With the switch in the ‘norm.’ position, thecurrent torque value of the lab vane is displayed in [Nm]. 

When the switch is in ‘max. Nm’ position, the big value occurring during the test run will be stored.The average fall rate of the display value is approx. 0.02 Nm per minute which should suffice to take readings from the display. 

Measuring Output

For recording the test procedure, e.g., via a computer assisted measuring software such as GEOsys, the appliance has been fitted with a DIN M18 output socket KFV71(Lumberg) on the right, where you can also tap a torquepro-portional measuring voltage with 0.5 Nm/V.

The output value will always be the current torque value. To measuring errors, the input resistance of the connected measuring system should be as high impedance as possible, but not be less than 10 kΩ. The measuring signal is provided at connector pins 5 (ground) and 4 (+)and is plug compatible with all our dataloggers or analogue inputs of the electric spindle testing units.

Vane Sizes

The vane for the device is made of four rectangular bladed stainless-steel vane attached to a short steel rod and the blades have different diameter and heights. The choice of the vane depends to soil strength which would be tested. The larger vanes are mostly used for the soils which are expected to have low strength values. 

• 10104-A5-001    VaneA 12,7 x 12,7mm

• 10104-A5-002    VaneB 12,7 x 19,0mm

• 10104-A5-003    VaneC 12,7 x 25,4mm

• 10104-A5-004    VaneD 20,0 x 30,0mm

• 10104-A5-005    VaneE 30,0 x 60,0mm

• 10104-A5-006    VaneF 40,0 x 80,0mm

• 10104-A5-007    VaneG 25,4 x 50,8mm

Holding Sample Tube Attachement

The apparatus has a suitable attachment to hold firmly sampling tube or cylindrical container at the base part of device.

The based part of the device is U shape type to enable the operator to use longer sample containers, but the device can be delivered with solid plate which is suitable to attach short sample tube if it is required.