【作者】 王忠；

【导师】 刘浩吾；

【作者基本信息】 四川大学 ， 岩土工程， 2001， 博士

【摘要】 从流固耦合理论出发，以有限元分析为主要研究手段，并辅之以半解析法，系统深入研究了水可压缩性、库底库底边界和水体的粘滞性对拱坝地震动水压力及坝体地震反应的影响及其规律性。在国内外首次提出了在平面波作用下液体-气体-固体动力系统的理论解，分析了大坝隔震气幕的力学性态，首次提出了基于理想气体状态方程的气幕隔震的压力有限元模型，研究了气幕隔震的减震机理和隔震效果，并深入论证了将隔震气幕运用于溪洛渡双曲拱坝的技术可行性和隔震效果，得到了具有重要科学意义和实际价值的成果。 基于库水体各类边界条件的有限元模型，系统分析了可压缩性对坝体动力响应的影响，表明水可压缩性对高坝动水压力强度和分布具有显著影响，而库底边界条件对大坝的地震反应有抑制作用。用半解析法分析了动水压力与与地震输入频率的关系以及库水表面重力波对动水压力的影响，表明动水压力的大小和地震输入频率有密切联系，而重力波的影响在工程计算中则可以忽略。 水体的粘滞性对库水中压力波的传播有吸收作用，它使得压力波能量沿传播方向呈指数方式衰减。本文用半解析法分析了对坝面动水压力的影响，并将该结果和库底吸收性做了对比，表明一定程度的库水粘滞性对动水压力的影响和库底吸收性的影响相同。 流固耦合理论中的基本问题之一就是对耦合方程的求解。本文首次将非齐次精细积分方法从线性荷载的特殊情况，推广到普遍情况，并导出了具体实用的分析方法，有力的推动了流固耦合及动力系统瞬态反应的高精度求解方法的新发展。 将本文首次提出的水体-气体-结构系统的平面波作用理论解和三维有限元模型，应用于溪洛渡双曲拱坝的抗震安全性和气幕隔震可行性研究中，表明气幕对高拱坝具有良好的隔震性能，可降低动水压力90％以上，坝体地震拱应力20％～30％，减震效果显著，并使坝体的抗拉安全系数从0.93提高到3.58。这 四川大学工学博士学位论文对发展高坝防震新技术，提高抗震安全性具有重要的科学意义和实际价值。更多还原

【Abstract】 Based on the theory of interaction of fluid-solid, The FEM and semi-analytic method are used to analyze the reaction of dam-reservoir subjected to seismic motion, the analysis includes the effect of water compressibility, reflectance of reservoir bottom and water viscosity. The mechanical properties, isolation mechanism and effects of hydraulic air cushions are studied theoretically. The plane-wave solution of the system of the fluid-gas-dam and the FEM model of gas isolations based on the state equation of ideal gas are presented for first time. Using this model, the technique feasibility to apply air cushions to Xiluodu high arch dam, located in Jinsajiang River, is explored deeply and demonstrated. The important results of scientific and practical significance are achieved.Based on the FEM model of the dam-reservoir system, the influence of water compressibility to the hydrodynamics is systemically analyzed and researched. It is showed thaf the water compressibility has significant effect to the size and distributing of hydrodynamics on the high dam, and the absorbency of reservoir bottom has a role as a damper on the dam-reservoir system. The semi-analysis method is used to analyze the relationship between hydrodynamics and the earthquake’s frequency and the influence of surface wave on hydrodynamics. It is concluded that the earthquake’s frequency has an important effect on the hydrodynamics, but the surface wave of water can be omitted in engineering design.In order to improve the numerical solution of coupled equation to the dam-reservoir interaction system, the high-precise integration is generalized from linear problem to the nonlinear one. This work promoted the development of high-precise integration applied to the coupled system of fluid-solid.The plane-wave analytic solution of the coupled fluid-air-solid system and the FEM model of air cushion isolations are applied to study the influence of air cushionon earthquake response of dams. The calculations show that air isolation will reduce the hydrodynamic pressure significantly and restrain the dam vibrations during earthquakes. If the dam and reservoir is isolated by air cushions, it will decrease the hydrodynamic pressures by more than 90% and the seismic stresses by 20-30%. The coefficient of anti-seismic safety will be risen from 0.93 to 3.58.This research is very valuable to improve the safety of high arch dams against strong earthquakes. It provides useful guidance for seism-resisting design of high arch dams subjected to earthquakes.更多还原