Influence of Non-Structural Elements on Dynamic Response of Multi-Storey Rc Building to Mining Shock
In the paper the results of calculations of the dy namic response of a multi-storey reinforced concrete buil ding to a strong mining shock originated from the main region of min ing activity in Poland (i.e. the Legnica-Glogow Copper District) ar e p esented. The representative time histories of accelerations regi st red in three directions were used as ground motion data in calcu lations of the dynamic response of the structure. Two variants of a numerical model were applied: the model including only structural e lements of the building and the model including both structural an d non-structural elements (i.e. partition walls and ventilation duct s made of brick). It turned out that non-structural elements of multi-st orey RC buildings have a small impact of about 10 % on natural freque ncies of these structures. It was also proved that the dynamic res pon e of building to mining shock obtained in case of inclusion of al l non-structural elements in the numerical model is about 20 % small er than in case of consideration of structural elements only. The p rincipal stresses obtained in calculations of dynamic response of mul ti-storey building to strong mining shock are situated on the level of about 30% of values obtained from static analysis (dead load). Keywords—Dynamic characteristics of buildings, mining shocks , dynamic response of buildings, non-structural eleme nts
Probabilistic seismic hazard analysis for mining-induced seismicity
Many examples have shown that the seismic activity accompanying underground mining works can be hazardous
both to underground staff and mining installations, as well as to ground structures. Due to their shallow focal depth,
smaller as compared to natural earthquakes mining seismic events can give rise to damaging ground motion.
The probabilistic seismic hazard analysis (PSHA) is a standard tool to estimate expected seismic impacts of
earthquakes. Mining-induced seismicity, however, significantly differs from the earthquake process. First, the seismic activity in mines is predominantly controlled by time-varying mining works, therefore the active zones are, by their nature, transient. Moreover, even during their lifetime, the activity of these zones is not stationary but changes considerable. Second, due to the heterogeneity of the rockmass fracturing process in mines, the magnitude distribution of seismic events induced by exploitation is complex and its modeling based on the Gutenberg-Richter's relation usually leads to large systematic errors of hazard parameters. Third, the ground motion resulting from weak mining seismic sources is strongly influenced by local path and site conditions and the attenuation relations from one region are poorly applicable to the other region. All these differences cause that the standard PSHA methods cannot be readily applied to mining seismic problems. A probabilistic approach to the seismic hazard assessment, radically adjusted to mining seismicity, is presented in this paper. In these modified procedures, locations and times of activity of the seismic zones that will be active in the future are deduced from programs of mining operations. From all mine areas of past seismicity experts select those whose mining and geologic conditions are expected to be similar to the conditions of the zones of future activity. Probabilistic characteristics of the seismic activity of these areas and their changes in time give rise to the alternative time dependent models of the future zone seismic activity. The model-free approach with the non-parametric kernel estimator of magnitude density is applied to represent the source size distribution. This approach ensures cumulative distribution function and related parameters estimate which are free from epistemic uncertainty and have of tolerable aleatory variability regardless the actual complexity of the underlying magnitude distribution. The attenuation relations, used to convert the probabilistic characteristics of the future seismic source into the probabilistic haracteristics of the future ground motion, are identified from multiple acceleration signals recorded in the region under study and therefore are linked to local conditions. Estimation of the relative local amplification factors and the use of spectral ordinates in addition to the peak motion amplitudes reduces uncertainty of this step of the hazard analysis. The alternative possibilities of the seismic process development in the future zones and the variants of ground motion generation and propagation are combined with the logic tree approach. The presented mining-induced seismic hazard assessment method is illustrated be a practical example from Legnica-Glogow copper mining area in Poland.
Research on Control and Planning of Soft-Wing UAV for Haze Removal
The existence of fog and haze has caused great pollution to the environment. The research of removing haze is a hot topic in recent years. In this paper, a special haze removal algorithm based on Soft- Wing UAVis proposed. In this algorithm, two track control strategies are designed based on the Soft-Wing UAV model transfer function. A SIMULINK platform based mathematical model of Soft-Wing UAV is built to testified effectiveness of the two track control strategies. An autonomous ergodic-planning algorithm with greedy strategy and foldback algorithm for Soft-Wing UAV is designed. Within the algorithm, the haze regional has been modelled, the cost matrix is constructed, and the planning and ergodic strategy is proposed. Finally, the experimental results validates the reliability of the algorithm in the application of haze removal with the proposed evaluation Index.