核电厂进水口直立式翼墙结构地基三维地震响应分析

以某核电站海域工程进水口直立翼墙为背景,运用FLAC~(3D)有限差分程序对直立式翼墙结构在地震作用时的动力响应进行模拟,结合PL-Finn液化后大变形本构模型,研究翼墙结构在动力荷载作用下的动力响应规律。从结构的位移时程、结构变形、超孔压比、液化区域等方面定量评价翼墙护岸结构的安全性。分析结果表明:砂土液化后发生流动使结构出现规律性残余变形,且随地震强度增加而变大。由地震惯性力和砂土液化共同引起的水平和竖向变形,在SL1作用下翼墙结构顶部水平残余变形0.05 m,竖向残余变形为0.07 m。在SL2作用下翼墙结构顶部水平残余变形0.26 m,竖向残余变形为0.16 m;与基底输入地震动相比,在翼墙结构顶部水平和竖直加速度放大4～5倍,且越靠近翼墙顶部处加速度呈现出明显放大效应。

Three-dimensional Seismic Response Analysis of the Vertical Wing Wall Structure at the Intake of a Nuclear Power Plant

Taking the vertical wing wall of the intake of a nuclear power plant as the background, in this study, we used the FLAC^3D program to simulate the dynamic response of the vertical wing structure under earthquake action. Combined with the PL-Finn constitutive model, we studied the dynamic response law of the wing wall structure under dynamic load, and quantitatively evaluated the safety of the wing wall''s revetment structure with respect to the structural displacement time history, structural deformation, excess pore water pressure ratio, and liquefaction area. The analysis results show that the structure experiences regular residual deformation due to the liquefaction-induced flow of sand, which increases with earthquake intensity. The horizontal and vertical deformations are caused by the earthquake inertial force and sand liquefaction. The horizontal residual deformation at the top of the wing wall structure under the action of SL1 was 0.05 m, and the vertical residual deformation was 0.07 m. Under the action of SL2, the horizontal residual deformation at the top of the wing wall structure was 0.26 m, and the vertical residual deformation was 0.16 m. Compared with the input ground motion of the bedrock, we found the horizontal and vertical accelerations at the top of the wing wall structure under the actions of SL2 and SL2 to be amplified by 4-5 orders of magnitude, whereby the closer the acceleration is to the top of the wing, the more significant is the amplification effect. The conclusions obtained in this paper can serve as reference for similar projects in the future.