空腔预应力闸墩优化研究

Research on optimization of prestressed pier with cavity

为降低预应力闸墩的拉锚系数,可在闸墩内设置空腔,以提高主锚索在闸墩颈部的预压效果,抵消闸墩正常工作时的弧门推力.以某水利枢纽工程预应力中墩为研究对象,采用三维有限元分析方法,研究了施工期和运行期最不利工况下空腔设置位置、长度和宽度对闸墩颈部应力和空腔周边应力影响.研究结果表明,空腔位置、长度对闸墩颈部和空腔周边应力影响较大,宽度对闸墩颈部和空腔周边应力影响较小;空腔应设置在预应力闸墩锚块内并靠近锚块上游面,其长度建议值为（0.3-0.5）闸墩厚度,宽度可根据施工方便程度来合理选取.

In order to reduce the pull-anchor coefficient of prestressed pier;the cavity can be set in the pier to improve the prestressed effect of the main anchor rope at the pier neck;and offset radial gate thrust during the normal operation of the pier.Taking the prestressed pier in a hydraulic project as the research object;a three-dimensional finite element analysis is used to study the influence of the cavity setting position;length and width on the stress of the pier neck and the periphery of the cavity at the most unfavorable conditions during construction and operation.The results show that the cavity position and length have a great influence on the stress of the pier neck and the periphery of the cavity;and the width has a little effect on it.The cavity should be set in the anchor block of the prestressed pier and close to the upstream surface of the anchor block.The length of the cavity is recommended to be 0.3-0.5 times thickness of the pier;and the cavity width can be selected according to the convenience degree of the construction.