CONSTRUCTION OF MINING ENTERPRISES AND UNDERGROUND SPACE DEVELOPMENT
Among the reliable tunneling complexes, without which it is impossible to create conditions for such a high-performance process, as mining of mine workings are geokhods. Since the geometric parameters of the external engine and the screw channel vary, the process of interaction of the geokhod systems with the geo- environment and with each other requires mathematical modeling. Modeling allows presenting schemes of interaction with various environments: loose (viscous-mobile) and strong. The mobility of the geoenvironment provides interaction along the entire supporting surface of the blade, so increasing the blade area leads to an increase in tractive effort. In strong rocks, the interaction occurs along the supporting surface of the blade, and the free surface may not touch the rock. Thus, in the interaction of the external propeller (HP) with the geoenvironment, the blade deforms; it is possible to form a region of crushing of the rock, and taking into account the elastic deformation in determining the geometric parameters of the blade and the canal will minimize the process of forming the region of crushing; when modeling the process of interaction of the VD with the medium, the load can be considered as uniformly distributed and equal to the ultimate strength of the rock for uniaxial compression.
The creation of machines for heavy mining conditions is impossible without solving the problems associated with the drive. The widely used hydraulic drive has a number of drawbacks that can not make it uniquely acceptable. More successful is the electric drive, which takes advantage of the stepping electric drive, but its scope is limited by the parameters of the hydraulic motors. That is why it is necessary to create a so-called discrete hydro motor drive that would allow generating pulses of small volumes with high frequencies to move the output links to specified distances with high accuracy in a wide range of speeds. This determines the relevance of the scientific and practical task under consideration. Conclusion: the use of dispensers will allow the implementation of discrete hydraulic drive systems, but for its final implementation it is necessary to justify the dynamic and geometric parameters of the device, as well as circuit solutions for the use of such dispensers.
Detailed investigation of mechanical, deformation and rheological properties of frozen soils is an actual issue, as they are basis of civil- engineering survey for underground constructions in permafrost holding more than 50% of the territory of Russia. The majority of modern software packages which calculate structures stability considering stress state of soils massive, demand knowledge of mechanical and rheological parameters defined by triaxial compression tests. The current article presents: estimation method of frozen soils rheological parameters by triaxial compression testing; required equipment and the research results. The samples of frozen soil 10 – 50 m depth from Kharasavey gas field were used as test material. Mostly they are presented by loam, clay and sand. The experiments were run at the range of temperature from −3°C to −6°C.. Triaxial compression testing was provided by the laboratory equipment which allows to run experiments in the mode of automatic load, maintenance and deformation processes registration. Test procedure of rheological parameters identification under conditions of long-term triaxial compression considered incremental load Stage duration was equal to 24 hours. The experiments were run until th specimen’s failure. As a result of the testing, mechanical, deformation and rheological parameters for frozen soils are defined at temperatures −3°C −6°C. The achieved results can be interpreted in different models (Mohr-Coulomb, Drucker-Prager, Tresca etc.). The described experiments were carried out at LLC Gazprom Geotechnology for the design of underground drill cutting s storages in permafrost.
POWER ENGINEERING, AUTOMATION, AND ENERGY PERFORMANCE
The increase in the capacity of cleaning and construction vehicles for high-capacity and energy-intensive mines calls for an increase in the supply voltage of cleaning and tunneling combines, as well as transport systems: from a voltage of 660 V switched to 1140 V, and now to 3300 V. This allows improving technical and economic indicators for clearing and access areas, as well as improving the reliability of local Power Supply Systems (PSS). However, this trend prevents the supply of underground electric networks with a voltage of 6 kV, in connection with which the problem arises of increasing the voltage of supply networks. To date, it has become possible to apply the 10 kV voltage to the operation, which is most acceptable for the use of electrical equipment for electrical networks and protection devices. Leading educational, research and design organizations were engaged in research on this issue. An analysis of the results of the research showed that switching to 10 kV voltage is justified and timely. At the same time, 35 kV voltage is not removed from the agenda, which is technically feasible and economically justified, but there are problems with the safety of its operation in underground workings, which requires appropriate refinement. This level of voltage will improve the quality of electricity. Conclusions: 1. Application of 35 kV voltage in the underground power supply system of coal and ore mines is advisable at a depth of more than 1000 m with a maximum load of at least 1000 kVA at the level of the stem cables. 2. Application of 35 kV voltage in underground electrical networks will allow to significantly improve the quality indicators of voltage, reliability, and economy of the system due to the current unloading of the most important element of SES, such as stem cables. 3. Analysis of the main parameters and characteristics of electrical mine electrical equipment gives reason to believe that it allows implementing a trend of 35 kV deep input to deep horizons of mines (mines) and placement of 35/6 kV substations on working horizons.
The electric power system of the Russian Federation was most developed in the 80-90s of the last century, after which there was an almost twofold decline in the generation and transmission of electrical energy in the system with subsequent growth. The main problem of fuel and energy complexes is the progressive aging of fixed production assets in conditions of increasing energy consumption requirements, which is a source of increased risk of major accidents. In this case, negative disturbances can arise both in the system itself and be external to it and can lead not only to a low quality of electrical energy but also to interruptions in power supply. The studies carried out to date are devoted to a quantitative assessment of the reliability of power supply systems and their equipment and do not take into account the effects of electrical equipment failures on the characteristics of production processes and the operation of technological machines. To consider the reliability of power supply systems in isolation from the operation of other systems (technological, relay protection, automation, ventilation, dewatering, etc.) means not to use the whole range of measures aimed at improving the reliability of electricity supply, as a result it is impossible to ensure the optimum level of reliability of electricity supply. Reliability of the power supply system must be evaluated taking into account the interaction of electrical equipment with the equipment of all production systems. The problem of increasing the efficiency of the functioning of industrial enterprises by optimizing the parameters of the reliability of power supply systems is topical and of great economic importance.