跨活断层倒虹吸明钢管对断层错动的适应性及抗震性研究

Study on adaptability to fault slide and aseismic behavior of exposed steel penstock for fault-crossing inverted siphon

本文结合某高地震烈度区跨活断层输水工程,采用有限元方法对倒虹吸明钢管对活断层错动位移的适应性及抗震性能进行了研究。结果表明:对跨活断层的明钢管,设置多个波纹管伸缩节,滑动支座和铰支座间隔布置,可有效适应断层错动位移;每段钢管上下游侧设有波纹管伸缩节,钢管刚度相对较大且集中了结构大部分质量,在地震作用下基本为整体运动,应力主要由内水压力产生;钢管轴向位移较大,导致铰支座支承环受弯严重,应尽量避免过多设置伸缩节,以提高结构轴向抗震能力;滑动支座能起到一定的基础隔震作用,铰支座可以对钢管结构位移加以限制,滑动支座和铰支座间隔布置不仅对适应地基不均匀变位有利,也有利于明钢管结构抗震,但应保证支座连接强度,并设置限位装置,防止管道滑落。

This paper uses finite element method to analyze the adaptability to fault slide and aseismic behavior of an exposed steel penstock for an inverted siphon that crosses an active fault in a high-intensity earthquake region.The results show that an effective measure for a better adaptability to fault slide is to arrange enough number of bellow expansion joints and install slide supports and hinge supports at certain spacing.By this measure,most of the mass is lumped on the penstock and each span of the penstock separated by the joints has a larger stiffness,so that under earthquake conditions the penstock can move rigidly and only its internal water pressure produce stresses inside its structure.Its axial displacement,however,will be greater and the support rings of hinge supports may be bent seriously.To improve its axial aseismic ability,excessive number of expansion joints should be avoided.The slide supports work as base isolation supports and the hinge supports restrict excessive horizontal displacement.Thus a suitable arrangement of both supports is advantageous in adaptability to differential settlement and also in aseismic ability.To strengthen the supports that must have enough strength,restraining devices should be used to avoid penstock sliding off.