储罐地震易损性数值仿真分析

为了研究储罐的抗震性能,忽略储罐罐壁的质量,将储罐中的液体质量简化为三质点体系模型,地基土由两个弹簧和两个阻尼器模拟.考虑罐体的平动和转动,建立了在水平地震激励下储罐的动力方程;给出了随机变量的概率模型和基于易损性理论的失效概率计算方法.通过对大庆某油库2×104 m3和5×104m3两种大型储罐进行数值仿真方法的地震易损性分析.结果表明:随着地震烈度的增大,储罐的易损性逐渐增大;5×104 m3储罐的抗震性能要好于2×104 m3储罐;2×104 m3和5×104 m3储罐的主要失效模式分别是抗失稳和抗提离.由此可见从多个失效模式对储罐进行地震易损性研究比从单一失效模式进行易损性研究更加科学.

Investigation seismic fragility of tank based on numerical emulation analysis

In order to study the seismic performance of tank, ignoring the quality of the walls of the tank, liquid quality of tank is simplified as three-particle system model. Soil is modeled by two springs and two dashpots. Considering translation and rotation of tank, dynamic equation is established under the horizontal seismic excitation. Probability models of the random variables and calculation method of disabled probabilities on the basis of seismic fragility theory are given out. The seismic fragility of 2 ×104m3 and 5 ×104m3 large-scale storage tanks of Daqing oil-room is analyzed by adopting numerical simulation methods. The numerical result shows that: the seismic fragility of tank gradually increases with the increase of seismic intensity, and the seismic performance of 5 ×104m3 tank is better than that of 2 ×104m3 tank. The main disabled mode of 2 and 5 ×104m3 tanks is respectively anti-instability and anti-uplifting. So, evaluating the seismic performance of tank form various modes is more scientific than from single mode.