| Reinforced concrete silo is widely used in the fields of coal,grain and cement because of its large amount of grain and small footprint,etc.In the grain storage industry,combined silos of related processes make group silos in order to increase production efficiency.However,at present,the group silos are mostly checked according to the empirical formulas and construction requirements of the single silo which is a lack of overall consideration for the group silos design under earthquake especially.Based on this,combining related research the dynamic characteristics,dynamic response and dynamic discharge over-pressure of column-supported reinforced concrete silos are analyzed by finite element methodIn this paper,the Overseas Gaoqiao Grain Reserve and terminal facilities project for the project background.This article mainly did the following work:(1)The modal analysis of column-supported single silo and group silos was carried out respectively,and the vibration frequency,period and vibration pattern of their respective first ten vibration modes were obtained.and the results were compared with the previous experimental values and theoretical values.It is shown that the higher the order of the mode of vibration,the more significant the combination of translational and torsional modes of the mode shape diagram.The frequency of every mode of group silos is higher than the single silo,and the simulated value is compared with the experimental value and the theoretical value.(2)By using El-Centro wave the simulation of the seismic time-history of the column-supported single silo and the group silos are done,the dynamic response of displacement,velocity and acceleration of the top of silo and the top of the column under the condition of full,3/4 and 1/2 storage material are simulated.It is shown that dynamic response decreases with the reduction of bulk.The full-silo conditions were simulated for the group silos,and the dynamic responses of the displacement,velocity,and acceleration of the side silo and the middle silo were compared and analyzed.It was concluded that the dynamic response of middle silo was greater than that of the side silo,and was compared with the experimental results.(3)Three-dimensional model of column-supported silos including funnel are established which improves defects in previous axisymmetric models.Static simulation and dynamic unloading simulation are carried out,through the Drucker-Prager elasto-plastic criterion,the contact algorithm between bulk material and the silo wall.The static side pressure simulation value is coincident with the Janssen theoretical calculation and test values.The over-pressure coefficient is increased obviously in the middle of silo and the connection between cylinder wall and column top.Based on the finite element simulation of silo,this paper probes into the dynamic characteristics of the silo and group silo,the dynamic response difference between the single silo and the group silo and the distribution of over-pressure during dynamic unloading process.It provides the numerical simulation basis for the seismic design and the dynamic unloading of the column supporting silo. |
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