THE PROBLEM OF DETERMINING THE DEFORMATION 
PROPERTIES OF SOIL 
[K voprosy opredeleniya deformatiznykh 
svoistv pochv] 
N. P. Rozhkov, A. V. Baukov 
(Scientific Reports of the Ukranian Agricultural 
Academy, 1973, Issue 100, pp. 100-115.) 
[Nauchnye Trudy USKhA (Ukrainian S-Kh. Akademiya) 
Vyp. 100, s. 100-115, 1973.] 
As is known, the soil is a complex elastic-viscous-plastic media [7] pos- 
sessing a whole series of properties, the study of which are very diffi- 
cult. Therefore, for improving the physical nature of the phenomenon oc- 
curring during the interaction of working tools of agricultural machines 
with the soil, we are ordinarily limited by a small number of indices of 
its condition. 
The process of deformation of soils, as has been shown by studies of 
V. G. Berezantsev [2], A. S. Kushnarev [10], and other authors, consists 
of two phases: 1. (phase of compression/local shear); 2. phase of sig- 
nificant shear. 5 
In the first phase a converging together of the particles occurs, and 
their density increases because of an isotropic compression. The force 
of the pressure during this does not exceed the limit of strength of the 
soil. 
With a further increase of pressure a second phase starts - the plastic 
flow of the soil along the surface of the limiting resultant (surfaces 
of significant shear). The limit of load in this phase depends on the 
coefficient of internal friction and cohesion of the soil. 
In the first phase between compacting pressures and relative deforma- 
tion of compaction (elastic and residual) there exists a linear rela- 
tion [1,3], characterized by the modules of deformation Ep. The magni- 
tude of it depends on the type of soil, its moisture density and method 
of loading [4,5,6,8]. 
The large interval of the values of the modulus of deformation [4,6,8] 
causes the necessity of determining its magnitude for each type and con- 
dition of soil with a definite speed of loading, which must equal the 
speed of movement of the soil working tools. 
The deformation corresponding to the first phase is made more sharply 
with an interaction of a smooth roller with the soil. During this it is 
suitably accurate to consider the speed of loading. 
We will examine the scheme of interaction of the roller with the soil 
(Fig. 1), the pressure of which does not exceed its limit of flow. 
