V. N. Oparin

Problems of nonlinear geomechanics. Part 1

In the study, an attempt is made to present the most important results of experimental researches on nonlinear geomechanics—a rapidly developing scientific trend in recent years—from single positions within the framework of Academician M. A. Sadovskys concept relative to the block-hierarchical structure of rock masses. The key role of the linear embedment coefficient of geoblocks for contiguous hierarchical levels, and the statistical characteristic of the average distances between the edges of cracks separating the structural blocks between themselves to the diameters of these blocks, as well as the scale factor of the phenomenon of the zonal disintegration of rocks around underground workings is demonstrated in the development of nonlinear geomechanical processes at various hicrarchical levels: from monatomic-crystalline to planetary scale. A number of major scientific problems, a solution of which demands particular attention of experimenters and theoreticians is formulated. The circle of problems touched upon in this part of the article concerns primarily the analysis of nonlinear quasi-static processes.

From the alternating-sign explosion response of rocks to the pendulum waves in stressed geomedia. Part II

The analytical review of the currently boosting nonlinear geomechanics and geophysics research toward developing the theory of the dynamic deformation of geomedia under powerful natural and induced impacts (explosions, rock bursts, earthquakes, etc.) is presented. In this context, the authors focus at: block structure hierarchy of rock masses in estimating quasi-static and dynamic processes in rocks under natural or induced disturbance; quantitative description of underground nuclear explosion effect on production and seismicity; experimental-analytical existence proof of previously unknown nonlinear elastic pendulum-type waves with unique dynamic-kinematic characteristics. It is highlighted that theoretical forecasting and, then, experimental discovery of the pendulum waves immediately associated with stress-strain state of rocks has spurred the development of brand-new methods and means for integrated seismic-deformation-electromagnetic monitoring of natural and induced earthquakes, rock bursts and other seismic events, as well as for the enhanced oil recovery due to vibration treatment.The authors emphasize the priority of creating a reliable scientific basis for prediction of real-time interaction of complex natural and geotechnological systems with the aim at developing and designing the geotechnologies of the future, based on the knowledge of features and regularities in the behavior of nonlinear mass-exchange physico-mechanical and mechano-chemical processes in deep and ultra deep mineral mining, and also express hope for the presented review being a helpful guide in the field of nonlinear geomechanics and geophysics.

Pendulum-type waves. Part II: Experimental methods and main results of physical modeling

Conclusions1. Investigations of physical modeling of pulsed actions on models of block media (with different material composition and characteristic dimensions of the subblocks) by energy-calibrated impacts confirmed the hypothesis expressed earlier by the authors about the possibility of existence of pendulum-type waves, the elementary carriers of which are geoblocks of a different scale level (μ-waves).2. An analysis of the regularities of formation of the spectra of the wave packets and graphs of the absolute displacements of the blocks, determined by the optical method, permitted concluding a resonance mechanism of occurrence of μ-waves, underlying which is the canonical relationship of the spectral modes for wave packets with respect to factor (√2)i, i=0, ±1, ±2, ±3, ... .3. The effect of the condition of canonical relationship of the spectrum in wave packets of μ-waves under certain conditions of energy actions can leads to the occurrence of the effect of anomalously low friction between interacting blocks (carriers of μ-waves) in directions orthogonal to the line of action of the external pulse.The work was performed with the financial support of the Russian basic research fund (grant No. 96-05-66052).

A NEW SCALE OF HIERARCHICALLY STRUCTURED REPRESENTATIONS AS A CHARACTERISTIC FOR RANKING ENTITIES IN A GEOMEDIUM

Conclusions1.Based on studies previously conducted at the Mining Institute, Siberian Division of the Russian Academy of Sciences in the field of nonlinear geomechanics and the results of analysis presented in a paper on the hierarchically structured makeup of metamorphic granite masses, therefore, it is possible to conclude that in processing experimental physical or geomechanical information, a semi-log or log-log scale on a base of ten A ∨ log A ↔ x ∨ log x and A = f(x), where A and x are functionally related quantities normalized in a special manner) is the most convenient and natural theoretical description of nonlinear processes in structured media.2.Recommendations are given for sampling the dimensions of the averaging base and discretization interval of a data file for graphic representation or computer analysis of experimental information, and also in smoothing operations performed in accordance with the sliding-window method.3.The canonical scale that we developed for hierarchically structured representations of physical information can be used as a ranking characteristic for entities in geomedia. This provides for the possibility of a spectroscopic approach to the identification of the atoms of the elements in Mendeleevs table or their mechanical compounds, which has come into widespread use in physics and chemical analysis; this would even be applicable, however, to analysis of nonlinear physical or geomechanical processes (quasi-resonance approach), including confirmation of the hypothesis of the existence of an acoustic-electromagnetic rainbow [7].

Interaction of geomechanical and physicochemical processes in Kuzbass coal

The paper presents laboratory and in situ research data on interaction of geomechanical and physicochemical processes in Kuzbass coal of various ranks, considering temperature effect. Under analysis is the relation of stress-strain state, temperature and infrared radiation of coal. The authors study the role of temperature and microstructure of coal in energy and mass exchange processes (variation of mass, volatile yield, specific surface, internal energy of methane adsorption capacity decrease and moisture content). Interrelation of outburst hazard and fire hazard in coal is discussed from the viewpoint of uniform stagewise thermomechanics and thermochemistry of coal behavior in the course of coal formation and extraction. The article introduces a generalized factor for quantitative description of petrographic properties of coal. Using this factor, the authors classify and describe petrographic groups of Kuzbass coal.

On Dynamic Behavior of “Self-Stressed/” Block Media. Part II: Comparison of Theoretical and Experimental Data

The evolution of seismic signals in the structured media is described by introducing nonlinear stiffness function of interblock interaction. The effects revealed experimentally were studied, i.e., concentration of block oscillation spectrum in the low-frequency region as the seismic signal moves away from the disturbed block to the peripheral ones and canonical subordination structure of wave packet spectral modes.

Evolution of stress-strain state in structured rock specimens under uniaxial loading

The comprehensive experimental studies into the change in the stress-strain state of rock specimens subjected to uniaxial loading until failure, using the automated digital speckle photography analysis shows that when the stress reaches 50% of the limit strength of the specimens, low-frequency micro-deformation processes begin in the specimens under slow (quasi-static) stiff loading. The amplitude of the deformation-wave processes depends on the level of the pre-set macro-loading. Wave packets are plotted for averaged microstrains obtained in sandstone and marble specimens under uniaxial compression. Fourier transforms are used to define the amplitude-frequency characteristics of four micro-deformation stages: elastic, nonlinearly elastic, post-peak and residual strength stages. Elastic oscillations with frequency 0.5–4 Hz appear at the pre-failure stage and continue at the post-peak loading stage.

Nonlinear Deformation Processes in the Vicinity of Mine Workings. Part II

The in-situ experiments with the use of borehole deformometers are carried out. It is established that the response to blasting is of the marked alternating character, and approaching of explosion foci to the measurement points leads to increase in strains with nonlinear dependence on the distance. The dimensions of geoblocks involved in the deformation processes and the velocity of their movement are determined.

Kinetics of seismic emission in coal mines in Kuzbass

The article gives the experimental evidence of effective use of the kinematic criterion χ, derived by Oparin for “apparent” velocities of pendulum waves based on deterministic description of seismic energy release in the Norilsk mine fields, in assessment of stresses and strains in coal beds in terms of the Polysaevskaya Mine, Kuzbass.

Cloud technologies in mining geoinformation science

The article discusses a new approach to implementation of a geoinformation environment for the mining geoinformation science problem solution using cloud technologies. In focus are the types of the cloud service as applied to the distributed geomonitoring networking for the wider range problem handling in mining. The authors describe specific structures of software support of the offered approach and exemplify problem solution in various spheres of mining geoinformation science.