New Equipment for Determining Friction Parameters in External Conditions: Measurements for the Design

Abstract

Friction parameters such as the angle of internal friction and the external friction of soils (bulk materials) show the possibilities of further material use. These are, for example, possibilities for soil processing, handling, and storage. The determination of friction parameters is usually carried out under laboratory conditions. For the possibility of determining the properties of soils outside the laboratory in terms of immediate material response, a laboratory prototype was developed. The main objective for its development was to determine the effect of the shape of the friction surface when “sliding” on the soil. This was achieved with the help of validation equipment designed to measure, test, and validate the processes of raking, material piling, material transfer and removal, and tool movement or sliding on or in a material. It was found that by using an appropriate speed and normal load, the Jenike method can be applied to determine the angle of external friction over a shorter distance with an error of about 6–7.5% from the values measured on a calibrated shear machine. The results also showed that the method can be applied to detect the shear stresses that arise when a tool is plunged into a material, and thus predict the possible increase in energy loss during the process.