Seismic Performance Analyses And Seismic Measures Of Long-span Coal-conveyer Gallery Subjected To Near-fault Pulse-like Ground Motions

The coal-conveyer structurein the thermal power plantsplays a key role in the normal operation of thermal power plants.Due to its own structural characteristics,in the past years of earthquakes,the coal-conveyer system structures in the disaster areas have suffered various degrees of damage,which has caused serious economic losses.At present,few studies have been performed on the seismic performance of coal-conveyer gallery at home and abroad,and moreoverthe seismic response of coal-conveyer gallery subjected to the near-fault pulse-like ground motions is much less.Therefore,there is an urgent need to conduct relevant research in such a field.The main research contents and results are as follows:Firstly,taking the typical coal-conveyergallery structure of a thermal power plant as the research object,the finite element numerical model was established,and the modal analysis was carried outwith the method of eigenvector.In addition,thenear-fault pulse-like ground motions with different pulse periods were selected by using the energy-based pulse-like ground motions identification method,and the main pulse components in the selected ground motions were removed,so as to obtain the corresponding non-pulse-like ground motions.Secondly,by the paper analyzed the internal force and displacement response of the coal-conveyergallery structure under the action of frequent earthquakes,and analyzed the impact of pulse-like ground motion on the seismic response of the structure under the condition of frequent earthquakes,especially when the pulse period is close to the natural vibration period of the structure.At the same time,the ratio between the calculated value of response spectrum and the calculated value of pulse-like and non-pulse-like ground motions under the action of frequent earthquakes was analyzed,and the variation interval of internal force or displacement of the coal-conveyergallery structurewas obtained.When considering the pulse effect,the internal force and displacement calculated by the response spectrum should be amplified in the actual structural design of the coal-conveyergallery structure,otherwise the dynamic response of the structure will be underestimated.At the same time,relevant seismic measures are taken to ensure the safety and reliability of the structure.Finally,the time-history analysis of the structure under the action of rare near-fault pulse-like and non-pulse-like ground motions was carried out.The results show that: under the condition of rare earthquake,the change curves of internal force and displacement of the structure are more obvious,and the amplification effect of the pulse effect on the response of the coal-conveyergallery structure is the most obvious in the case of three-direction input.Under the action of pulse-likeground motions,the horizontal displacement of pillar top of the coal-conveyergallery will cause more serious damage than expected,and the mid-span deflection of the steel truss istoo large for the allowable deformation limit of the equipment manufacturer,which will seriously affect the applicability of the structure and the safety of ancillary equipment.In the actual design work,the seismic performance of the coal-conveyergallery structure is mainly studied in the case of frequent earthquakes.When the structure of the coal-conveyergallery is designed in the high-intensity area,the seismic performance of the structure can be strengthened by reasonable layout,in-depth analysis,shock absorption and isolation and other measures.