The article is devoted to the analysis of approaches to modeling the stress-strain state of a block rock mass in the vicinity of a single mine workings and in the area of rock cantilever influence during the development of the Khibiny apatite-nepheline deposits. The analysis of the existing in international engineering practice ideas about tectonic disturbances as a geomechanical element and the experience of predicting the stress-strain state of a block rock mass was carried out. On the basis of the analysis, the formulation of the basic modeling tasks is carried out and its main results are presented. Methodological recommendations for solving similar problems were developed.
The article presents a numerical solution of the spatial elastic-plastic problem of determining the stability of the tunnel face soils at the intersection of disturbed zones of the soil mass. The relevance of the study is related to the need to take into account the zones of disturbed soils when assessing the face stability to calculate the parameters of the support. Based on the finite element method implemented in the PLAXIS 3D software package, the construction of a finite element system "soil mass-disturbance-face support" and modeling of the intersection of the disturbed zones of the soil mass were performed. To assess the condition of soils, deformation and strength criteria are taken. The deformation criterion is expressed by the value of the calculated displacement of the tunnel contour in the face, and the strength criterion - by the safety coefficient until the maximum values of the stress state are reached according to the Coulomb–Mohr criterion. The results of the study are presented in the form of histograms of the safety coefficient dependences on the distance to the disturbance at different bending stiffness of the face support structure, as well as the isofields of deformation development. The parameters of rockfall formation in the face zone at the intersection of zones of disturbed soils were determined. The local decrease in strength and deformation properties in the rock mass along the tunnel track should be taken into account when assessing the stability of the tunnel face and calculating the parameters of the support. Within the framework of the constructed closed system, a qualitative agreement of the simulation results with the case of a collapse in the face during the construction of the Vladimirskaya-2 station of the St. Petersburg Metro was obtained.
The article describes the role of geomechanics for forecasting the development of geosystems and ensuring the safety of mining operations during the transition to a new technological paradigm. The state and prospects of development of the mineral resource base, including the Arctic zone of the Russian Federation, are considered. The directions of technological breakthroughs and the possibility of transforming industrial production based on «cross-cutting» technology and the digital economy are presented. The analysis of geomechanical problems was carried out considering advanced technological changes and the rapid growth of requirements for the preservation of the Earth’s interior and natural landscapes. The concept of the development of geomechanics and geodynamics to ensure rational subsoil use in terms of the use of «breakthrough» technology is proposed, and the need to integrate scientific and industry collaboration into the system of engineering and professional education is shown.
The article examines a method of forecasting strength properties and their scale effect in fissured rock mass using computational modelling with final elements method in ABAQUS software. It shows advantages of this approach for solving tasks of determining mechanical properties of fissured rock mass, main stages of creating computational geomechanic model of rock mass and conducting a numerical experiment. The article presents connections between deformation during loading of numerical model, inclination angle of main fracture system from uniaxial and biaxial compression strength value, size of the sample of fissured rock mass and biaxial compression strength value under conditions of apatite-nepheline rock deposit at Plateau Rasvumchorr OAO «Apatit» in Kirovsky region of Murmanskaya oblast. We have conducted computational modelling of rock mass blocks testing in discontinuities based on real experiment using non-linear shear strength criterion of Barton – Bandis and compared results of computational experiments with data from field studies and laboratory tests. The calculation results have a high-quality match to laboratory results when testing fissured rock mass samples.
The aim of the article is to develop a method of forecasting the state of stress of the ore mass around excavations for ores of weak and medium strength. The paper presents experimental studies on the deformation of ore samples of low and medium strength in the forging equipment in conditions of volume stress state. A physically nonlinear model is used to describe the deformation process of ore mass. The study of the stress state of physically nonlinear ore mass around excavations of round and valuated cross-sections is performed. Values of coefficients of tangential stress concentrations on excavation contour are found for different types of ore. Solutions to physically nonlinear problems in preparatory excavations in the development of the Yakovlevskiy deposit of rich iron ore using a slicing method are considered. Methods for forecasting the stress state in rock mass around mine excavations can be used to assess their stability in the mining of ore of low and medium strength at the Yakovlevskiy iron ore deposit and in the rock and soil masses.
The development of prediction method of earth surface settlement during the tunneling in heavy geological conditions of megalopolises was the purpose of the article. The experimental-analytical and numerical prediction methods of earth surface settlement during tunneling by mechanized tunnel boring machines are proposed and justified. The volume balance of earth surface settlement and volume of additionally excavated soil during tunneling are accepted as initial condition for experimental-analytical prediction method. The comparison of predicted and experimental data of earth surface settlement in different countries is performed. The prediction with numerical methods is produced in 3D with application of elastic-plastic soil body model. The matching of numerical calculations data and data of experiments and analytical calculation is revealed. The proposed prediction methods may be used for geotechnical substantiation of projects of tunneling in heavy geological conditions.
Method of normal load prediction on vertical shaft lining which is constructed in nonlinear rock mass is suggested. It is supposed, that limit state zone is formed around excavation. The deformation properties of rock mass in the suggested method are determined according to nonlinear rock model. In order to predict stress and strain state around excavation the equations of deformation plasticity theory are used. The Mohr-Coulomb strength criteria is taken as a yield surface.
The comparative analysis of the stress-strain state in the circuit and in the vicinity of a single generation of circular and arched curves of elastic and non-linear strain diagram types of rocks. Graphic dependences were obtained by the finite element method, reflecting the nature of the stress-strain state. The actual values of the tangential stress concentration factor on the circuit were obtained using non-linear functions.
The parameters of underopencast rock mass stress-strain condition for Koashva deposit are defined. The estimation of influence of surface development with opencast on the stress-strain distribution in the mass is revealed. Research is revealed with appliance of finite-elements method.
In the learned article the substantiation of the mutual influenced tunnel’s temporary support elements stress-strain state prediction technics is adduced. The problem is sold in three-dimensional arrangement with allowance for building technology. The analysis of numerical simulation results is adduced. On account of this analysis the main ways of solution for such problem class is spotted.
The three dimensional stress distribution in tunnel set with allowance for relative influence and building sequence is investigated. To complete the task the finite elements analysis was used. The values of stress concentration factor and conformities of stress distribution in the «lining – mass» system are estimated. The relative influence of each tunnel in tunnel set with allowance for building sequence is identified.
The parameters of the stress state of nearbord massif of deep open pit on the example of the field development of the V.Grib. This research was done by numerical simulation using finite elements method.
Method of excavation support and tunnel lining design is worked out. Stiffness of soil strata is considered as nonlinear elastic. The problem is solved in plane strain condition according to elastic theory. The distribution of average load on excavation support is given.
Numerical modeling of deep excavation construction is done in plane strain condition. The influence of boundary condition, contact condition between soil and structures, constrain of cantilever wall, thickness of the wall and anchors on the strain condition of the soil is found.
The main features of the entries supports in theinfluence zone of open pit and second working are established. Research was carried out using a numerical modelling by finiteelements method.
In this article the analysis of the stress-strain state of the external and internal contours of the lining, which appears during the process of the drilling of tunnels with using of contledge of the face which applied in Tunnel Boring Machines, is adduced. The finite element method diagrams obtained the minimum and maximum principal stresses on the outer and inner contours of output. Relationship obtained in the surface sediments depending on the depth of the tunnels.
The intelligent technology of designing of the constructions of pillar underground station is adduced. Station is building with applying of low-settle technology, which takes into consideration main stages of the building process. The scheme of interaction of the system «support lining-soil massif» was accepted as basic scheme of calculations. The calculations of the stress-strain condition of constructions was performed with applying of finite-elements method.
Comparison of results of calculations of the tangential stresses on the inner contour of tunnel lining and radial stresses on the outer contour is done. Stresses are found by solving the problem of interaction in geomechanical system «lining-ground massif» in 2D and 3D model (single layer tunnel lining and double layer tunnel lining). Area of correct application of 2D models are revealed.
In this learned article the analysis of reinforcing effect, which appears during the process of the drilling of tunnels with using of contledge of the face which applied in tunnel boring machines, is adduced. By applying of the finite-elements method the family of graphical relations, which reflects the processes of the development of displacements, is approached. For the reason of analysis of these relations the optimal value of contledge of the face if maximum permissible displacements of the earth surface are known have been suggested. The influence of the main strength characteristics of Couloumb – Mohrs’s theory of strength on stability of the face of the tunnel and the necessary value of contledge of the tunnel’s face are defined.
The methodic of the field observation for the processes of deep benchmark displacements and configuration of the local observing station is offered. The analysis of the results of the field observations for the displacements of the ore pillar is accomplished, the isolines of settling and the isolines of the average speed of settling of the ore massif is offered.
Side deep pits are complex engineering structures, which depend on the state of mine safety. As bating and opening new horizons in the development of mineral deposits open as a result of longterm at the edge array of pits are changing the natural stress and accumulated fatigue, which leads to deformation of the sides, ending in some cases, catastrophic collapses and landslides. Prevention of dangerous destructive strains edge arrays depends on reliable assessment of emerging strains.
Simulation-based finite element method of forming the features of the stress-strain state in pillar at the ore body downstream horizontal layers with a mined-out space. The obtained regularities of redistribution of stresses in pillar and surrounding rock massif are allowed to substantiate an effective way to reduce the bump hazard in mining operations.
According to geological data received on the Jakovlevsky deposit, the spatial geomechanical model has been developed. During the analysis of the is intense-deformed condition pictures of distribution of horizontal pressure and vertical displacement on border ore потолочины and карбоновой thicknesses have been received. It is established that the zone of clearing works essentially influences distribution of pressure and movings to border ore roof and carbonic thicknesses. By results of modeling it is possible to estimate possibility of formation of vertical water spending cracks in an ore roof.
According to geological data which was received at the Yakovlevsky deposit, the volumetric model was developed. This model taking into consideration the driving of the mine through zone of weakening. During the analysis of the stress-strain condition near the mine the character of distribution and numerical results of tangential and longitudinal stresses have been revealed. The zone of weakening affects to the distribution of stresses and displacements around the mine. To select the parameters of the lining support it is necessary to take into consideration weakenings and contacts in the ore massive and the distance for these zones.
The article deals with geomechanical and hydrogeological problems under the Yakovlevsky ore deposit development including variations in strength properties. The estimation of feasible underground water inrush inside the mining excavation is done. In situ results of ore strata deformation around excavation are discussed. Numerical modeling of stress and strain in the waterproofing ore pillar due to partially backfilling of excavation is carried out.
In the article the analysis of consolidating effect from application of the anchor fastening, which using at driving of transport tunnels in the conditions of North Caucasus is produced. The change of the stress-strain condition of the rock massive, which is weaked by the mining of the circular outline is certain with the finite-elements method. On the basis of the executed design the row of graphic dependences, which describes changing of the sizes of limitary areas depending on strength and deformational properties of the rocks. Due to results of the conducted work the direction of further researches is seted.
Classification of radioactive waste by the degree of its activity is given. Basic requirements to the construction site of radioactive waste repository or burial site are specified. Possible constructive solutions of underground repositories are briefly considered and a detailed description of the spiral structure of RAW repository is given. The influence of temperature and radiation on physical and mechanical properties of concrete and clay is estimated. The character of temperature field distribution around the underground RAW repository in time is obtained. The stress-strain state of the support was evaluated and loads on the support were found under the combined action of temperature and rock pressure, taking into account changes in the physical and mechanical properties of concrete and clay.
The results of in-situ measurements of vertical displacements of the tunnel lining of the St. Petersburg subway are presented. The 3d-model of interaction between soil and tunnel lining subjected to initial geostatic stress state is considered, and vertical displacements of the lining along the tunnel are used as an additional boundary condition. The calculated tangential stresses in the lining are compared with in-situ results of crack zone formation.
The paper provides information on the distinctive features of the geological structure of the Starobinsky deposit's formations and the current mining methods used at Levels II and III. Two methods of selective potash mining using the "loading-unloading-dumping" technology are proposed. The economic effect at realization of recommended schemes is calculated.
The main ore base of the Russian aluminum industry is the deposits of the North Urals bauxite basin. The deposits are developed at depths of 900-1000 meters, and the design and opening of new horizons is planned at depths of 1500-2000 meters. The mining and geological conditions of deposit development become sharply more complicated at greater depths. To ensure the required volumes of bauxite production under such conditions, it is necessary to solve the problem of safe mining operations at deep horizons of mines.
Выполнено геомеханическое обоснование высоты водозащитной потолочины между верхним горизонтом отработки рудной залежи и карбоновой толщей водонасыщенных пород и оценка толщины и прочности искусственного защитного перекрытия при их совместном взаимодействии с учетом порядка отработки очистных камер.
Обоснованы критерии для оценки устойчивости обнажений выработок Яковлевского рудника и зависимости для расчета вертикальных и горизонтальных нагрузок на их крепь в рыхлых рудах, основанные на теории свода. Предложены типы и параметры крепей выработок рудного массива.
The problem is posed and calculations of stresses and weight coefficients in laminar roof at rock fracture are carried out. The calculations showed that increasing the energy of rock fracture reduces the influence of diffraction processes. The condition of brittle fracture of rock roof under dynamic loading is obtained.
A complex of experimental and theoretical studies on substantiation of the main provisions of environmental technology of development of shock-hazardous deposits at great depths is carried out. The laws of distribution of dynamic stresses around excavations under the action of seismic waves from rock shocks, which are the basis for the creation of earthquake-proof supports, are revealed. Fastener designs are proposed.
In-situ measurements of tunnels deformation for Saint-Petersburg subway are given. Time dependable wave character of tunnels deformation in the form of rising and lowering was discovered. It was established that periodical rising and lowering of tunnels occur along the track section with disrupted rock mass and tectonic fissure. It was suggested that tunnel stability prediction technique is based on rate of it displacement.
The thermoplastic problem under the Coulomb condition about the stress-strain state of the soil mass around the chamber with a deposit of radioactive material is considered.
On the basis of the laws of changing the parameters of the dynamic stress field during the interaction of seismic waves with the mine workings the requirements to the seismic resistant armoring of mine workings in the zones of rock bumps and mass explosions are formulated. The operability of traditional types of anchors under dynamic loads is evaluated. The optimum design of fortification of excavations in the shock-hazardous areas is a combined support from steel-polymer or reinforced concrete anchors with a solid filling of the boreholes with a fortifying composition enhanced by piles of long (up to 3.5 m) reinforced concrete anchors in the place of wave exit on the contour of the excavation. The length of the anchors is chosen according to the tensile stress zone overlap.
On the example of Mikhailovsky and Yakovlevsky deposits the problems of development of rich iron ores of KMA related to their deep occurrence, taking into account difficult engineering-geological conditions of construction of underground mines and harmful consequences of ore mining by open pit for the natural environment are considered. The results of complex tests of physical-mechanical properties of loose rich ores, which have not been sufficiently studied yet, are presented. Forecast of land alienation and soil contamination caused by an increase in the volume of overburden during further exploitation of Mikhailovsky open pit is given. For the Yakovlevsky mine, the most effective layered systems of development of the ore body with stowing of the mined-out space were studied. The descending order of mining of blocks with the device on the top layer of protective overlap to prevent subsidence of the overlying strata with the formation of channels of hydraulic connection with the coal aquifer is recommended.
Field observations of the displacement of rocks around the preparatory and cleaning workings (operations) of SUBR mines (shafts) establish the effect of stratification of the roof of workings (operations) and cleaning chambers under the action of seismic waves. The shifts are traced to a depth of up to 4 m, and almost instantaneously, at the moment of the rock impact. When modeling the process of interaction of a flat straight wave with workings (production) of rectangular, vaulted and shapes of cross-section, it is shown that the probability of reaching the limit state of the host rocks due to the maximum difference in the main pressure (stress) is higher in workings (production) of rectangular and more shapes. Based on the revealed dynamics (changes) of seismic pressure (stress) and regularities of deformation of the host rocks, the design of reinforcement (strengthening) of the roof of chambers and joints of excavations (workings) with deep reinforced concrete anchors was developed.
One of the drastic measures to increase environmental safety and safety in operation of nuclear power plants is to use underground space for their location. Operating experience of underground nuclear power plants (UNPP) has shown high levels of their safety and reliability of the reactor and processing equipment as well as environmental protection. The rise in UNPP safety is secured by the rock massif strength, its insignificant penetration properties, reactor opening impermeability and system of gas gathering and outgassing through lining and drainage. To reduce long-term exposure of the walls of the reactor opening to high temperatures in case of a failure, a water sprinkling system is provided. In case of an emergency increase in pressure in the reactor opening, the gas-vapour mixture will pass through the rack massif and, due to its low temperature, gas condensation will occur and the wave front propagation will decrease in speed. Quantitative assessment of security arrangement demonstrates that the highest level of security is achieved at UNPPs with double casing and UNPPs with pressure release. One of the drawbacks of UNPPs is an increase in their cost and construction time. According to various estimates, the increase in the cost of UNPP construction relative to the construction of a land-based NPP is 15-25%, and the construction period increases by 1.5-2.5 years. An effective way of reducing construction costs for UNPP is to combine it with burial grounds for radioactive waste, that are adopted for recycling and storing waste both produced by the UNPP and brought from other nuclear enterprises of the region.
Blast wave influence on rock stability in mine openings is given an account of. Results of mathematical modelling of a dynamic stress field created in the massif due to wave interaction with the mine opening have been analysed. A stress field influenced by short wave blasts has been studied. Equations of dynamic balance for theoretically elastic environment, supplemented with boundary and initial conditions for the corresponding components of stress tensor, serve as the basis of a mathematical model developed by V.V. Karpenko and G.A. KoIton. The set of 5 equations was solved using S.K. Godunov numerical technique. Input data are assumed on the basis of the mining conditions at the Severniy (Northern) mine (blast hole diameter - 76 mm; blast type - granulite AC-8). A particular case of blast influence at 10 m range between the charge and the gallery roof (r =370) has been studied. Distribution diagram parameters of the forward-moving elastic wave compression phase have been determined using analytical dependence for a cylinder-shaped charge blast (amplitude σ o = 9.6 MPa, period of time t - 1.2 ms, speed C 1 - 4500 m/s). It has been demonstrated, that form the direction of the forward-moving wave, refracted and diffracted waves create in the massif an extensive zone of radial tension stress, peaking at 1.6 at the distance of 0.8-1.0 R from the contour. In lateral areas, the blast wave produces concentration of tangential compression stresses up to 1.6 σ o . An estimation of mine destruction caused by the energy of dynamic development has been given. Besides dynamic compression and tension stresses, repeated blasts and impulse stress load and relief on the massif also influence stability of the mine openings. An estimation of rock stability criteria at the entry contour during joint action of static and dynamic stresses has also been given.
Проектируемый для разреза «Березовский - I » Канско-Ачинского угольного бассейна угольный склад состоит из 5-10 бункеров емкостью по 12000 т каждый. Основной его функцией является обеспечение непрерывности подачи угля потребителям ...
Исследованию различных аспектов процесса деформирования и разрушения пород при проведении подземных взрывов посвящено большое число исследований ...
В работе содержатся фундаментальные экспериментальные исследования прочности и деформируемости 23 типов горных пород, а также гипс., бетона, цементного камня и кирпича ...
Подготовительные горные выработки обычно испытывают воздей ствие бпорного давления, вызванного проведением очистных работ. Для решения ряда практических вопросов большое значение имеет качественная и количественная оценка этого воздействия на напряженное состояние пород вблизи них. Впервые влияние очистного забоя на распределение напряжений в окрестности выработки квадратной формы с гладким контуром исследовалось А. С. Космодамианским. На практике, однако, они встречаются различных форм с гладкими и неровными контурами ...
Для определения места рационального расположения полевых подготовительных выработок, выбора типа крепи, установления технических условий для ее проектирования и решения других практических вопросов необходимо оценивать напряженное состояние породного массива вблизи этих выработок ...
Устойчивость горной выработки в основном определяется размерами области неупругих деформаций, образующейся в ее окрестности. Эта область может быть найдена расчетным путем ...
Величина вывалообразований пород, нагрузка на крепь горных выработок, перемещения их контура определяются в основном размерами области неупругих деформаций, образующейся в окружающем выработку породном массиве. В практике поддержания большинство подготовительных горных выработок испытывает влияние опорного давления, причем нет расчетных методов оценки этого влияния на размеры области неупругих деформаций ...
В практике поддержания горных выработок часто встречаются случаи их взаимного влияния. Особенно существенное воздействие оказывают очистные работы на напряженное состояние вблизи подготовительной выработки. Решения этих задач сложны и громоздки, в связи с чем они в основном выполнены для случаев взаимного влияния выработок одинаковой формы. Известны лишь некоторые решения для разных форм. Однако эти решения из-за сложности конечных формул не получили значительного распространения для определения напряжений в окрестности выработок. Необходимо создать более простые методы расчета ...
Кировский рудник комбината Апатит отрабатывает пластообразную апатито-нефелиновую залежь со средней мощностью 150—200 м, расположенную между ийолит-уртитами в лежачем боку и рисчорритами в висячем. Простирание залежи северо-западное, 310—320°, падение под углом 30 ±5°. Крепость по Протодьяконову: руды /=6—8, вмещающих пород /=10— 12. Проведение горизонтальных и вертикальных выработок зачастую сопровождается внезапным отделением (с резким треском) кусков породы от контура и забоя выработки. Это явление, называемое стрелянием, наблюдается при проведении выработок как по руде, так и по породам висячего и лежачего боков. Активнее всего стреляние проявляется сразу после взрывных работ при проходке выработок ...
В данной работе рассматривается напряженное состояние упругоползучих горных пород вблизи закрепленной горной выработки с контуром, имеющим технологические неровности. При решении данной задачи используется напряженно-деформированное состояние вокруг незакрепленной горной выработки. Поэтому рассмотрим сначала решение этой задачи ...