考虑桩土-隔震层-罐体相互作用的隔震储罐地震响应分析

Seismic response analysis of isolated tank considering pile-soil-isolation layer-tank interaction

为了研究桩土、隔震层与罐体相互作用对15×104m3隔震储罐地震响应的影响,桩与隔震层采用弹簧-阻尼单元,罐体采用壳单元,流体采用势流体单元,基于ADINA建立数值仿真分析模型,在8度El Centro地震动激励下,应用Newmark数值积分方法进行地震响应分析。结果表明:隔震储罐基底剪力和基底弯矩相对于非隔震储罐明显降低,储罐罐壁加速度沿罐壁高度方向近乎平动,但对波高的控制效果不明显;除罐壁顶部外,动液压力明显降低;隔震后,罐壁有效应力和环向应力减震效应明显,对轴向应力和径向应力影响较小,建议从安全角度考虑,储罐非隔震设计时不考虑桩土作用,隔震设计时考虑桩土对罐体的影响。

For researching the influence on the seismic responses of storage tank with volume 15 × 104m3 and isolation,which comes from the interaction among pile-soil,isolation layer and tank body,inputting El Centro ground motion with seismic intensity Ⅷ,using the numerical integration method of Newmark and imitating piles and isolation with spring-damping element,tank body with shell element and liquid with potential-fluid element,we get the seismic responses of the structure that： the base shear force and base bend moment of the isolated storage tank decrease apparently compared with the non-isolated one,and the accelerations of the tank wall vary smoothly along the tank height,but the sloshing wave height is not controlled well;dynamic liquid pressures decrease obviously except at the top of the tank;after using isolation,the effective stress and circle stress of the tank wall decrease well,but the axial stress and radial stress don’t change obviously.We propose not to consider the pile-soil effect while designing storage tank without isolation and to consider this effect while designing storage tank with isolation.