Moscow State Mining University, Moscow, Russia:

Koshelev A. E., Post-graduate Student, e-mail: geomeh62@yandex.ru

This paper includes the experimental researches for the definition of deformation module of rock samples of rock salt in a complex stress state and in uniaxial compression mode. The experiments were held on the cylindrical samples of rock salt. Samples were made from a core material from the 970-1000 meters depth of Kaliningrad region. Seven samples were tested.

The deformation modules were defined on the same sample, in uniaxial compression mode and in complex stress state.

At the first stage of experiment, the deformation module was defined according to the standard method. There followed an equivalent increasing of radial and axial stresses to 20 МPa. The sample was being stood at the hydrostatic compression for a time, at which there was a stabilization of the load sensors data, i. e. the stress relaxation time. There was increased the axial load at an invariable radial load. The deformation module in a complex stress state was defined by the load legs.

The research results showed that on the average, the deformation module in a complex stress state ЕD' is 3,8 times higher than the deformation module ЕD, which was defined by a standard method.

According to the analysis of the received results, there follows the conclusion: there is needed the transition from standard research methods to research methods with preliminary hydrostatic compression along with the further analysis of influence of a stress field, at which the rock sample is in a massif on its physical and mechanical properties.