How accurate is a pocket penetrometer?
Pocket Penetrometers are not individually calibrated and therefore, no calibration certificates are supplied. An error of up to 1/2 division on the scale, equivalent to 0 to 0.124 TSF, is possible with the instrument.
What does the pocket penetrometer measure?
The “pocket penetrometer” is specifically used to determine the penetration resistance of top layers (measuring depth 5 mm) and of samples in the field or in the laboratory. Measuring range 0.5 MPa. When pushing the instrument into the ground, the pin encounters a force of the ground.
What soil property do pocket penetrometer measurements give?
However, penetrometers are designed to give quantitative measurements of soil penetration resistance for a more precise correlation with properties such as bearing value, safe soil pressure, rolling resistance, trafficability of wheels or crawler tracks on soil, relative density, crop yield, and tilth (Davidson, 1965).
What is hand penetrometer?
Gilson Soil Pocket Penetrometer also called a hand penetrometer is constructed of stainless steel. It is a simple, lightweight, handheld device made for instant estimates of the unconfined compressive strength of cohesive soils. The calibrated steel spring is plated for rust resistance.
What is unconfined compressive strength?
A measure of a material’s strength. The unconfined compressive strength (UCS) is the maximum axial compressive stress that a right-cylindrical sample of material can withstand under unconfined conditions—the confining stress is zero.
How is soil strength measured?
Soil strength is a measure of the capacity of soil to resist deformation and refers to the amount of energy that is required to break apart aggregates or move implements through the soil. It is measured in megapascals (MPa) which indicate penetration resistance.
How does a Shearvane operate?
Hand-Operated Shearvane – A shearvane is another direct reading instrument to determine the unconfined compression strength of soils. This instrument is pressed into the vane of a soil and rotated. The soil strength can then be read directly on the wheel of the device.
How do you calculate unconfined compressive strength of soil?
The Unconfined Compressive Strength is calculated as
- Initial Area Of Specimen (A0) = π4D02.
- Change in Length or Deformetaion △L = Dail Reading in mm.
- Axial Strain (∈ ) = △LL0.
- Load (Kg) = Proving Ring Reading * Proving Ring Constant.
- Corrected Area = A01−∈cm2.
- Stress (δ ) = LoadCorrected Area Kg/cm2.
How do you find unconfined compressive strength?
What is the pocket penetrometer?
It is a simple, lightweight, handheld device made for instant estimates of unconfined compressive strength of cohesive soils. Although it does not replace laboratory Unconfined Compressive Strength Test Systems for the determination of unconfined shear strengths, the Pocket Penetrometer is a valuable tool for providing approximate values quickly.
What is the unit of compressive strength of a penetrometer?
Most penetrometers available today contain units of tons/ft 2 or kg/cm 2, and the compressive strength is read directly from the gauge. Some common conversions are: A pocket penetrometer is a primative instrument that is subject to many errors such as non-uniform soil.
What is the compressive strength of soil measured by a pocket penetrometer?
The pocket penetrometer measures the compressive strength of the soil. Most penetrometers available today contain units of tons/ft 2 or kg/cm 2, and the compressive strength is read directly from the gauge. Some common conversions are: 1 ton/ft 2 = 2000 psf = 13.9 psi. 1 kg/cm 2 = 98.1 kPa.
Which penetrometer should I use?
Adapter foot is recommended when testing extremely low strength cohesive soils. A dial pocket penetrometer offering greater capacity and sensitivity than others. Adapter foot is recommended when testing extremely low strength cohesive soils.