Geomechnical model testing has been widely applied as a kind of research technique in underground engineering problems. However, during the practical application process, due to the influence of many factors, the desired results cannot be obtained. In order to solve this problem, based on the measurement requirements of the model test, combined with FBG(Fiber Bragg Grating) sensor technology and traditional measurement methods, an FBG monitoring system, Micro-multi-point displacement test system, resistance strain test system and surrounding rock pressure monitoring system are developed. Applying the systems to a model test of the tunnel construction process, the displacement in advance laws of tunnel face, radial displacement distribution laws and surrounding rock pressure laws are obtained. Test results show that a multivariate information monitoring system has the advantage of high precision, stability and strong anti-jamming capability. It lays a solid foundation for the real-time data monitoring of the tunnel construction process model test.
The analysis of changes in the mechanical properties of wooden mining cribs under the influence of different types of exploitation loads is the question for which deals with many domestic and abroad research centers deal with. High The high interest in this subject results from the increase of the conducted depth exploitation, which contributes to the increase in both the vertical pres-sure and the complexity of geological – mining conditions and in- the intensification of natural hazards. Another reason is the tendency of decreasing the thickness of the exploited ores deposits. Wooden crib support is used Both both in underground ore, hard coal and salt mining is used wooden crib support. Mining cribs with various configurations are especially useful for the reinforcement of excavations workings behind the front and for further strengthen of the crossings. In particular, additional reinforcement support in the form of wooden cribs (pile supporting), which shall be left empty or filled with waste rock is applied in the ore mining in places where found extended rooms or drifts are found or in places with degraded roof conditions, applies additional reinforcement support in the form of wooden cribs (pile supporting), which shall be left empty or filled with waste rock. During underground ex-ploitation is produced waste Waste rock, which comes from the access, prepar-atory excavations and from ongoing field of exploitation is produced during underground exploitation. In the case of the underground exploitation of cop-per ore, waste rock is used to fill voids after exploitation as rock stowing. It is also used for filling mining wooden cribs, as an artificial support and for harder transportation roads. This paper presents the results of the laboratory strength tests performed on models of four-point timber cribs, built with beams set horizontally, at the ge-ometrical scale of 1:10. In the laboratory research Research wooden cribs models with size 200 × 200 × 200 mm and 100 × 100 × 100 mm were used in the laboratory. The paper describes the maximum loading capacity of the cribs consisted consisting only of beams and filled with waste rocks. In addition, a vertical and appropriate strain of cribs at maximum force was shown. On the basis of laboratory research it was found that the use of the same number of timbers and the management of waste rocks, the filling of the four-point cribs with the waste rocks allowed several times to increase its support to be increased several times.
Rising technical standards of customers, legal requirements and the trend to minimize maintenance effort raise the thermal, mechanical and tribological loads on components of combustion engines. In this regard, emphasis is laid on improving the piston ring - cylinder liner tribosystem, one with the highest energy losses. An efficient performance has to be guaranteed during its lifetime. Tribological investigations could be carried out on engine test benches, but they are highly cost-intensive and time-consuming. Therefore, a damage-equivalent test methodology was developed with the analogous tribological model, "ring-on-liner". The research was carried out under two characteristic operating conditions. One with a "standard" operating system, modelled in line with ideal lubrication conditions, and the other "extreme abrasive" operating system, typical to a system running on a lubricant contaminated by abrasive particles. To optimize the tribological loading capacity of the cylinder liner, with focus on these two operating conditions, numerous nitride coatings have been investigated. The key aspects being seizure resistance, running-in characteristics and long term wear behaviour.
The methane hazard is one of the most dangerous phenomena in hard coal mining. In a certain range of concentrations, methane is flammable and explosive. Therefore, in order to maintain the continuity of the production process and the safety of work for the crew, various measures are taken to prevent these concentration levels from being exceeded. A significant role in this process is played by the forecasting of methane concentrations in mine headings. This very problem has been the focus of the present article. Based on discrete measurements of methane concentration in mine headings and ventilation parameters, the distribution of methane concentration levels in these headings was forecasted. This process was performed on the basis of model-based tests using the Computational Fluid Dynamics (CFD). The methodology adopted was used to develop a structural model of the region under analysis, for which boundary conditions were adopted on the basis of the measurements results in real-world conditions. The analyses conducted helped to specify the distributions of methane concentrations in the region at hand and determine the anticipated future values of these concentrations. The results obtained from model-based tests were compared with the results of the measurements in realworld conditions. The methodology using the CFD and the results of the tests offer extensive possibilities of their application for effective diagnosis and forecasting of the methane hazard in mine headings.