地震作用下水库坝体与水体相互作用数值模拟

Numerical simulation of the interaction between dam and water in reservoir under earthquake excitation

地震作用下水库坝体受迫振动,推动坝后水体波动,造成水体动压作用于坝体,形成坝-水耦合作用,影响坝体安全。为了评估坝体振动引起的水面波动及坝体所受动水荷载作用,建立坝体动边界条件下的不可压水体运动数学模型,模拟了地震波作用下的坝后水体波动和动力荷载。结果表明,在忽略坝体自身弹性变形的条件下,地震作用下坝体激发的水体表面波动、波高和波能随地震波振幅增大呈线性增长;波高随水深呈非线性增长;坝体所受动水压力主要来自附加质量力和静水压力,地震作用下库区地面的水平运动对涌浪波高和坝体动水压力影响较弱。

During earthquakes,hydraulic dams are subjected to forced vibrations which induce surface water waves and hydrodynamics pressure behind the dam.Such dam-water coupled interactions may affect dam safety.In order to evaluate the influence of surface waves and hydrodynamic pressures on dams,a mathematical model is established for incompressible flow with moving boundary conditions to simulate the seismically excited surface waves and hydrodynamic pressures.Simulation results show that under the assumption of negligible elastic deformation of the dam,the height and energy of surface waves increase linearly with the vibration amplitude of the dam;the wave height increases nonlinearly with water depth of the reservoir.The primary fluid forces on the dam are the added mass force and the hydrostatic pressure.The horizontal movement of the ground under the reservoir has a minor influence on the hydrodynamic forces on the dam.