The surface shear stress apparatus manually measures top soil friction of an undisturbed soil sample and displays the results digitally. The equipment is suitable for soil samples with a diameter of 100 mm.
Easy manual operation
Accurate measurement principle and digital read-out
Developed in cooperation with Christian-Albrechts University, Kiel
Excellent price-quality ratio
Sample size Ø 103x100 h 30 mm
Allows for the determination of shear strength using a modified Mohr-Coulomb’s equation
Especially suitable for education application
 
Description
The determination of very thin soil layers, such as soil crusts, requires very sensitive and very accurate equipment. In addition, the equipment should allow very small vertical stress application during measurement. Our surface shear test apparatus meets these requirements. Included in the set are:
Erosion test apparatus
Weights 50-2000 gr
Various accessories
The apparatus was developed in cooperation with Christian Albrechts University Kiel in Germany, a leading institution in soil compaction research. Read the interview with Prof. Horn of Kiel University for more information. 
Shear strength measurement 
Altered soil functions, in particular reduced hydraulic conductivities and impeded aeration, influence the top soil layers. This has an important effect on vulnerability to erosion, in particular.
Soil stability is a decisive factor for erosion risk reduction. Soil stability is determined by shear resistance or the angle of internal friction, depending on or varying through soil-water pressure and humus content. Soil shear resistance will increase with increasing organic carbon content. Air-dry soil state samples will result in the smallest resistance to shearing in comparison with the range of water content applied. The effect of bulk density on soil shear strength depends on the water content and is distinct for a higher range of vertical loads.
Applications
Erosion
Geotechnical engineering
Geo-Hydrologic research    
Basic material research
User groups
Laboratories
Universities
Research institutes
Educational institutes
Specifications - weight
Weight container: for about 40 g - 1.08 hPa
Weight 1: 50 g - 1.35 hPa
Weight 2: 100 g - 2.70 hPa
Weight 3: 200 g - 5.40 hPa
Weight 4: 500 g - 13.51 hPa
Weight 5: 1000 g - 27.01 hPa
Weight 6: 2000 g - 54.02 hPa