地震动差动下高压输电塔-线体系的纵向反应

考虑地震波以有限波速传播时所引起的地震行波效应,基于建立的高压输电塔-线体系空间有限元模型,利用在多点输入下考虑几何非线性的动力时程分析法,研究了体系纵向地震作用下的反应特性,并和一致地震动输入下的反应情况进行比较。结果表明:行波输入既可以增加又可以降低输电塔的地震反应,这与行波波速、地震动性质、输电塔档距以及输电塔-线体系中导(地)线的松紧程度有关;行波输入使导(地)线跨中竖向位移增加十分明显,但使导(地)线跨中纵向位移减小,同时行波输入使导(地)线的轴力增加十分明显。由此得出结论:高压输电塔-线体系地震反应受行波波速影响很大,考虑地震行波效应的影响是十分必要的。

Longitudinal response of the power transmission tower-line system considering seismic differential motion

The seismic waves propagating with limited speed will cause the traveling wave effect.Based on the established finite element model of the high-voltage transmission tower-line system,the authors research the longitudinal responses of the system,which are analyzed by using the dynamic time history integration method under multiple support excitation considering the geometric nonlinearity,the seismic responses under traveling wave effect are compared with those under uniform excitation.The results show that the traveling seismic wave excitation can increase,or decrease the seismic responses of the transmission tower-line system,which are related to the traveling-wave velocity,the feature of seismic ground motion,the span of transmission tower and the tightness of the line of long-span transmission line system;the traveling wave effect obviously increases the line's displacement responses in the vertical direction,but decreases the line's displacement responses in the longitudinal direction.At the same time,the traveling wave effect obviously increases the line's axial force in a large scale.A conclusion is drawn that the traveling wave velocity has a great effect on the responses of high-voltage transmission tower-line system and it is necessary to consider the traveling wave effect.