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Shear Vane Tester
The T174 pocket vane tester has been designed to measure the undrained shear strength (Cu) of cohesive soils, up to 240kpa.
Shear Vane Tester 16-T174
The design is very similar to the well known 'Geonor' shear vane. It consists of a cylindrical body containing a torsional spring and three interchangeable vanes of different sizes.The appropriate vane is chosen for the expected strength of the soil to be tested.
The T 174 vane can be used both in situ and in the laboratory for soils having Cu = 24 t/sqm (240 kpa). The T 174 is particularly suitable in soft to medium cohesive soils where other tests do not provide adequate accuracy.
Vane T 174 is suitable for use in severe environmental conditions. The wire of the torsional spring, for example, is made of stainless steel as are the other parts of the instrument.
To test an undisturbed zone the vane is forced 5 - 6 centimetres into the soil. Deep measures can be performed using extension rods.
The choice of three different sizes of vanes allows a good accuracy of undrained shear strengths to be obtained for a relatively wide range (0 - 240 kpa).
The sensing part of the T 174 is a torsional spring; 360 rotational degrees are produced by approximately 0.5 kgm of torque. When the upper part of the instrument is turned by its handle an angular displacement is created between the two cylindrical parts (upper and lower parts). The value of this displacement is proportional to the applied torque.
Undrained shear strength (Cu) values are read from a scale etched on the vernier.
The height/diameter ratio is 2 for all the vanes. The vane sizes are designed so that:
* for the medium size vane (20 x 40mm) the Cu values are read directly from the scale (0 - 120 kpa);
* for the larger vane (25.4 x 50.8mm) readings on the vernier are to be divided by 2 to get the Cu values (0 - 60 kpa);
* for the smaller vane (16 x 32mm) readings on the vernier are to be multiplied by 2 to get the Cu values 0 - 240 kpa).
16-T174 Shear Vane Tester