Разработка месторождений полезных ископаемых невозможна без адекватного представления о свойствах как полезного ископаемого, так и вмещающих пород.Устойчивость подземных объектов и сооружений определяется способностью пород сопротивляться повышенным нагрузкам, возникающим вследствие перераспределения горного давления в процессе добычи полезного ископаемого.Зачастую именно растягивающие напряжения являются причиной обрушения кровли горных выработок.Одним из основных источников информации для проектирования горнодобывающих предприятий являются лабораторные исследования поведения породных образцов в различных режимах нагружения.Целью данной работы является формирование ключевых методических подходов к определению прочностных, деформационных и энергетических характеристик соляных пород при прямом растяжении в лабораторных условиях.Объектом исследования являются соляные породы Верхнекамского калийно-магниевого месторождения

Potash and salt deposit development is always associated with the risk of inrushes of fresh waters into stopes and mine flooding. This article considers experimental and theoretical approaches to mining safety and mine protection from flooding that are based on an informative interpretation using mathematical modelling results of instrumental and geophysical studies regarding mechanical properties and stress-strain state of undermined rock mass. A comprehensive implementation of these methods provides adequate mathematical modelling results and allows increased validity of predictive estimates related to stability of structural elements and integrity of water-blocking strata when it comes to the room-and-pillar method.

This work is devoted to investigation of spatio-temporal localization of deformation at the direct uniaxial tensile of sylvinite with using of digital image correlation method and acoustic emission technique. For the implementation of direct tension there was used a special reversing device allowing to convert compressive force into tensile. Samples are concreted into the device before the experiment. Sequentially photographed images of side surfaces of specimens were used to reconstruct the distribution of components of displacement vector field and strain tensor on the side of sylvinite samples under uniaxial quasi-static tension. As result of obtained data analysis it is found that the deformation process occurs as two consistently following forms of spatiotemporal localization: a system of equidistantly located stationary foci of localized deformation and a single stationary dissipative localized structure. Areas of specimen outside the localization zones are in the undeformed state, also as result of uniaxial quasistatic tension of specimen it is established that the zones of localized deformation can be tensile as well as compressive. The transition from one localization form to another occurs in the maximum stress vicinity and is accompanied by a sharp decrease in the concentration parameter. Concentration parameter characterizes the degree of interaction between defects of different scale levels through their elastic fields and can be estimated from the acoustic emission data. Analysis of dependence of the spatial period of localized deformation bands on the size of computational cell showed that localized deformation bands are self-similar structures and process of deformation is localized at the grain boundaries minerals composing the sample.

The authors consider a number of geomechanical monitoring methods for the underworked salt rock behavior, including visual control of its specific structural features, measurement of displacements using contour and depth reference points, and assessment of stresses in the surrounding rock mass. It is proposed to assess stresses in salt rocks using long spacing measurement methods without modeling-based recovery of stresses from measured strains if possible.

The research of potash salt rock deforming and damaging features has made it possible to develop the method of load bearing element state examination by chamber-and-pillar system. This method consists in instrumental control of pillars by geophysical and in situ methods with following prognosis of their residual life by mathematical simulation methods.

The results of field research of rock salt deformation under sustained uniaxial compression show that the viscoelastic Maxwell medium adequately characterizes time-dependent behavior of deformation parameters. The paper presents the accelerated test procedure and defines the long-term strengths for various types of rock salts from the Upper Kama Potash Deposit.