渭河拦河闸闸室抗震安全复核

Seismic safety review on Weihe River sluice chamber

以渭河拦河闸为例,基于ADINA有限元分析软件,建立拦河闸三维有限元模型,采用振型分解反应谱法对闸室结构进行地震动响应计算分析,并根据计算结果对拦河闸进行抗震安全评价。计算结果表明:拦河闸闸室结构前5阶振型主要体现为横梁和机架桥结构的振动,符合一般规律;边孔横梁与机架桥联接部位以及机架桥与闸墩联接部位出现了较大拉应力,其最大拉应力数值超过了混凝土动态抗拉强度标准值,但考虑局部配筋量后,拉应力数值满足安全需求;在地震作用最不利工况下,拦河闸整体闸室结构抗滑稳定安全因数为1.68,满足安全需求;拦河闸抗震安全满足标准要求,其抗震等级评定为A级。

The seismic intensity of the area is adjusted from Ⅶ to Ⅷ where the Weihe River barrage project is located.To ensure the safe operation of the Weihe River barrage project, it is necessary to carry out seismic safety review research on the project.At present, most scholars use the quasi-static method to check the seismic calculation of the sluice structure.The sluice belongs to a complex three-dimensional space structure, and the calculation is simplified only according to the conventional plane method, so the calculation result has a large error.In recent years, with the rapid development of computer technology, finite element numerical simulation technology has been widely used in the seismic analysis of sluices, but how to evaluate the safety of the area where the tensile stress exceeds the tensile strength of concrete is less studied.Given the problems existing in the seismic safety review of sluice structure, based on the finite element numerical simulation technology and ADINA finite element analysis software, an analysis method combining finite element numerical simulation and structural mechanics calculation was proposed.This method could effectively make up for the shortcomings caused by the simple use of finite element numerical simulation and could provide the corresponding basis and reference for the similar sluice seismic safety review.Taking the Weihe River sluice as an example, a three-dimensional finite element model of the sluice was established.The seismic response of the sluice chamber was calculated and analyzed by the mode decomposition response spectrum method, and the seismic safety evaluation of the sluice was carried out.Among them, for the area where the tensile stress exceeds the tensile strength of concrete in the finite element, combined with the actual reinforcement amount of the part, according to the flexural capacity of the normal section, the maximum bending moment of the section in the area where the stress exceeds the limit was obtained.The maximum bending moment on the section was deduced according to the calculation formula of normal stress of flexural members.Finally, the area where the tensile stress exceeded the tensile strength of concrete could be rechecked by comparing the calculated normal stress results with the finite element stress calculation results.In addition, based on the finite element calculation results of each node of the bottom plate of the lock chamber, the anti-sliding stability of the lock chamber structure could be calculated.The first five vibration modes of sluice chamber structure were mainly reflected in the vibration of beam and frame bridge structure.The results show that the fundamental frequency of natural vibration was 6.33 Hz under the condition of no water and normal water storage, and the natural frequency did not decrease obviously after considering the effect of hydrodynamic pressure.Under the earthquake action of normal water storage condition, large tensile stress appeared at the joint of side hole beam and frame bridge and the joint of frame bridge and pier, and its maximum tensile stress exceeded the standard value of dynamic tensile strength of concrete, but considering the local reinforcement, the tensile stress met the safety demand.Simultaneously, large compressive stress appeared at the corner of the frame bridge and other geometric mutation, and the maximum compressive stress did not exceed the standard value of concrete dynamic compressive strength, which met the safety requirements.Under the most unfavorable seismic condition, the safety factor of the anti-sliding stability of the whole sluice chamber was 1.68,which met the safety requirements.According to the Guidelines for Sluice Safety Evaluation(SL 214—2015),the seismic safety of the sluice met the standard requirements, and its seismic grade was Grade A.