Loading on support is defined by geomechanical, technological and geometrical parametres. At комбайновой technologies of carrying out of developments loading decreases in 1,5-1,6 times. Rigid dependence of size of loading on quality of filling закрепного spaces remains. Bearing ability of arches from СВП-27 and СВП-33 exceeds bearing ability of arches from СВП-22 accordingly on 33 and 76 %. Bearing ability of an arch with the account of plastic deformations of a steel increases on 32-42 % in comparison with elastic calculation.
The design procedure of loadings on arch support unilateral rectangular interfaces in an ore file of Jakovlevsky deposit КМА is offered. The settlement scheme corresponds rigid and plastic model of deformation of an ore file in a roof of interfaces. A major factor defining size of loading on overlappings of interfaces, emptiness in a roof after filling there are. Low efficiency of flat overlappings of interfaces on chamber frames and advantages of overlappings of interfaces by arches from profile SVP with horizontal couplers from арматурной steels of armature was revealed. Possibility of operative calculation of loadings and a choice of parametres of overlappings on conditions of durability and stability of bearing elements of support in ores of various types is proved.
Result of research is definition the zone of influence of sewage treatment works and their character for developing nearbord stocks Koashva opencast. The analysis of changes in the stress-strain state of massif around development workings in stages mining substages depending on their position relative to cleaning area. The research was carried out using a numerical modelling using the finite elements method.
The transformation of the stress condition of embedded border diastrophic bloc rock of the «pillar-working» system is considered, in combined action of geostatic tension, lateral and transversal tension wave, generated by rock bump. It is supposed that the tension wave front are parallel to the adjacent strata media discontinuity. Under this condition, in the article the influence of the critical tension levels on the roof and pillar rocks stress condition.
An approach to the estimation of amplitudes, periods and durations of elastic seismic waves, both longitudinal and transverse, generated by rock impacts characterized by dedicated energy is proposed. Calculations of stress and mass-velocity diagrams of elastic seismic waves from rock impacts are given, and a comparison of the calculated and real diagrams of a rock impact characterized by an energy of 10 kJ is given.
The scheme of vault hypothesis formation and the calculation method of loading on KMP-A3 arch support are presented. The presence of the outcrop contour in the ore massif of the Yakovlevskoye deposit is taken into account. Loads on the support in loose, medium-density and dense ores were determined.
The evaluation of the flat slab fasteners used at the Yakovlevsky mine structures is given. Designs and standard sizes of elements, rational zone of action of the support, application interfaces are determined. The expediency of the use of the support with an arched overlap, which has a greater load-bearing capacity and operational reliability, is substantiated.
По результатам испытаний прочности закрепления анкеров различных типов в богатых железных рудах установлена возможность крепления выработок в массиве анкерами «Swellex». Креплением опытного участка подтверждена работоспособность анкеров при условии затяжки обнажения, предупреждающей просыпание рудной мелочи. Предполагается ограничить область применения анкерной крепи выработками с коротким сроком службы, подлежащими в дальнейшем закладке бетоном.
Рудный массив Яковлевского месторождения представлен в основном рыхлыми и плотными разностями железно-слюдковых мартитовых руд, отличающихся низкой прочностью и устойчивостью в обнажениях. При проходке применяется буровзрывная технология с креплением выработок арочной податливой крепью из спецпрофиля. Под влиянием взрывов контур выработок деформируется, при этом деформации продолжаются и после установки крепи. Приведены количественные и качественные результаты наблюдений за формированием закрепного пространства, определены факторы, оказывающие значительное влияние на величину переборов руды и даны рекомендации по их снижению.
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.
The active mine workings are considered as full-scale models. It is shown that the database containing the data on mining-geological conditions, types, parameters and states of mine workings support, adapted for the selection of full-scale models according to the similarity conditions, allows to use effectively the accumulated experience of underground workings operation to justify the reliable decisions at the development of new sections of deposits.
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.
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.
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.
Штанговую крепь, согласно действующей временной инструкции. рекомендуется применять лишь в породах крепостью не ниже 3 (по шкале М. М. Протодьяконова). По предварительным расчетам применение штанговой крепи в штреках, пройденных по мощным угольным пластам, в частности, на гидрошахтах Кузбасса, должно дать значительный технический и экономический эффект. Поскольку коэффициент крепости угля мощных пластов часто не превышает 0,3—0,5, а угольный массив характеризуется значительной трещиноватостью, необходимо было обосновать возможность применения штанговой крепи в сложных условиях. В связи с этим потребовалось выявить характер деформирования слабого трещиноватого угля вблизи выработок, закрепленных штанговой крепью при различных углах падения пластов ...
