FIELD: testing equipment.
SUBSTANCE: invention relates to the field of "Physics of material contact interaction" of the four-blade rigid stamp of the working tip for testing the material medium in the well or an array by the method of rotary cutting. The device of blade tip is equipped with a registrar of continuous recording of torque Mi from the axis of the tip and its angle of rotation α°i at time t, and the torque on the axis of the tip or the angle of its rotation is set as incremental steps, kept on each step in time t to stabilise the indicators Mi or α°i, while the loading device is made in the form of a flat disc with suspended loads to create the moment Mi on the axis of the blade tip through the worm gear. When rotating of the blade tip by the worm gear through the line of rods with the cam device disconnecting rotation the torque M0 is measured after recording - the rotation of the line of rods in the array while the blade tip is disconnected and the moments (Mj+M0) - on the axis of the tip with the rods at their rotation in the array of the environment: (Mm+M0) - the limit of proportional deformation of ground elastic-visco-plastic medium under the blades of the tip, (Mmax+M0) - the cutting of medium by the blades of the tip (Mdev+M0) - the resistance to rotation of the medium amount cut-off by the blades. The graphs 
or 
are made, and the readings of the stabilised values of the torque Mtor1, M"б" are taken, as well as the corresponding angles α°tor1 and α°"б" of rotation of the tip blades at an initial (first) critical pressure 
under the blade and in overcoming the influence of gravitational pressure p"б". For the soil the following is calculated: 1) the specific cohesion c"стр"=(Mmax-Mm)/B=(Mdev-M0)/B; 2) the angle of internal friction 
3) the relative share γdev=c"н"/(hcos2φ"стр"), where c"н"=c"стр" [2-tgφ"н"/tgφ"стр"], φ"н"=arcsin[2sinφ"стр"/(1+sin2φ"стр")]-φ"стр"; 4) gravitational pressure p"б"=(γ"стр"h-c"стр")ctgφ"стр" at torque on the axis of the blade tip M"б"=τ"б"·B=γ"стр"h·B; 5) the coefficient of the total lateral pressure ζ"стр"=sinφ"стр"·cos3φ"стр", ζ"н"=sinφ"н"·cos3φ"н" and the coefficient of total relative transverse medium deformation ν"стр" and ν"н"; 6) the module of elasticity of the medium depending on the E.N. Hrustalev 
and 7) the module of total deformation of elastic-visco-plastic soil medium depending on E.N. Hrustalev 
(kg/cm2), where the constant is 
and for peat the following is counted: 
EFFECT: improved accuracy and informativeness of study of the medium by rotary cutting with obtaining the true strength and deformation characteristics of the medium.
11 cl, 12 dwg, 3 tbl
