It is established that the development of a localized plastic strain during compression of samples of rocks (sylvinite, marble, and sandstone) deformed by different micromechanisms has an autowave character. It is shown that the velocity of propagation of autowaves arising in the samples under compression is 10−5 to 10−4 m/s (0.3 to 3.0 km/g) and is close to the velocity of slow waves observed in the Earth’s crust after earthquakes or rockbursts.

Uniaxial and triaxial compression tests are standard methods of determining the strength and deformation characteristics of rock salt samples. The results obtained from such tests can provide useful data for assessing the deformation behavior of pillars in mining deposits. Relative axial and lateral strains were measured by two gauges installed on the motley sylvinite and rock salt samples. Studies on the influence of sample shape (ratio of the height of the samples to its diameter) rock salt on their mechanical properties were performed by tests on core materials. The triaxial compression tests were performed under axial load at a constant lateral pressure. The triaxial compression test datawere used to construct the uniformrelationships of Chanyshev's theoretical model.

The paper presents the theoretical determination method for rock strength properties under uniaxial and triaxial compression. The experimental values of ultimate strengths of dolomite and granite samples are used as the initial data. The correlation between the calculated and experimental data has been stated.

For the purpose of estimation of strength and defomation characteristics of quasiplastic rocks, the complex loading tests (according to Karman scheme) were performed. The obtained data were used to construct the constitutive relationships of A.I. Chanyshev's mathematical model.

Spatiotemporal distributions of local components of the distortion tensor of quasi-plastic materials-saliferous rocks (sylvinite)-have been studied under active compressive straining conditions using double-exposure speckle photography techniques. The strain localization patterns are presented and the features of macroscopic strain inhomogeneity are considered for inelastic behavior of the material. Results obtained for the slow wave processes in deformed saliferous rocks are compared to analogous data available for ionic crystals.

The article describes theoretical determination approach to strength limits in rocks exposed to triaxial compression (von Karman scheme). This approach involves experimental results of uniaxial compression or tension strength limits, or one of them, as the input information. Agreement of the calculated and experimental values for different hardness rocks has been achieved, which is displayed in forecasting positions of stress circles under different stress states.

The results of parameter measurements for saliferous rock deformation during volumetrical stress are given.

Experimental investigation has been conducted to study the deformation parameters of saline rock samples (variegated sylvinite (bed B) and rock salt (underlying bed) of the Verkhnekamsk potassium deposit) of cylindrical shape with the diameter d = 38 mm and height h = 76 mm under bulk compression. The experimental findings show that at the same lateral pressure the rock salt strength is by 20-25 % higher than for variegated sylvinite. The influence of lateral pressure on breaking strain in the interval 0-8 MPa is quite accurately approximated by a linear dependence. In this case, the deformation characteristics for sylvinite and rock salt almost coincide. The rock salt samples exhibit greater softening than sylvinite, which is due to their higher brittleness. Generally, the absolute values of most of the studied strength and deformation parameters increase with lateral pressure growth. Exceptions are the secant modulus of deformation and drop modulus.

To describe complex loading of semi-brittle materials, the constitutive relations “stress — deformation” are proposed. These relations are employed to describe the behavior of a titanic alloy under biaxial tension. Different deformation states are analyzed, including the transition from perfect to imperfect plasticity and vice versa.

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A sensor for measuring movements in block rock mass through boreholes is presented. Being an organic part of multichannel instrumental set, the sensor ensures revealing of deformation changes in the controlled zones of block geomedia, which is of key importance when stress variations and fatigue failure in rock mass are determined.

An optoelectronic micrometer display sensor for determining deformations in samples of rocks and models of block geomedia is presented. The sensor is equipped with a microprocessor data collection system for the on-line detection of deformation changes, which is of fundamental importance when determining stresses and failures in rock samples.

Design of a probing device to measure lateral borehole strains is presented. The probe is equipped with a data-collection system to support on-line measurements, which is of great importance for the control of stressed rock pillars at underground mines.