基于高阶时域人工边界条件的坝-水相互作用分析方法

A dam-water interaction analysis method based on the high-order time-domain artificial boundary condition

在大坝的抗震分析和设计中,应该考虑大坝与半无限库水之间的动力相互作用。地震作用下结构与可压缩水之间动力相互作用分析的关键问题是模拟波在无限域水中的传播。基于一种稳定且便于工程应用的时空局部高阶人工边界条件,建立地震作用下坝-水相互作用的有限元分析方法。该时域整体分析方法恒稳定,且对倾斜坝面或有库底淤积泥砂等复杂工况下的坝-水相互作用分析都具有高精度。通过数值算例揭示了坝面坡角和淤砂层厚度对刚性坝面动水力的影响:动水压力最不利位置约靠近坝水交界面底部,坝面底部动水力峰值随坝面坡角的增大而增大,垂直坝面的坝底动水力峰值最大。另外,淤积泥砂有吸收库水地震反应能量的吸能作用,淤砂层越厚,吸能效果越明显。

The dynamic interaction between the dam and the semi-infinite reservoir water should be considered in the seismic analysis and design of the dam. The key problem in the analysis of dynamic interaction between structures and compressible water under earthquake is to simulate wave propagation in the infinite domain. A finite element analysis method for dam-water interaction under earthquake is established based on a stable spatio-temporal local high-order artificial boundary condition which is convenient for engineering application. The time-domain analysis method is stable and has high accuracy for the analysis of dam-water interaction under complex conditions, such as inclined dam-water interface or the sediment at the bottom of reservoir. Through numerical examples, the influences of dam slope Angle and sediment thick Ness on hydrodynamic pressures of rigid dam surface are revealed. The most unfavorable position of hydrodynamic pressure is near the bottom of the dam water interface. The peak value of hydrodynamic pressures at the bottom of the dam water interface increases with the increase of the slope Angle of the dam-water interface, and the maximum value is at the vertical Angle. In addition, the sediment can absorb the seismic energy, and the thicker the sediment layer is, the more obvious the energy absorption effect is.