砼坝减震气幕与土石坝溢流柔性护面的模型试验

【作者】 张晓丽；

【导师】 刘浩吾；

【作者基本信息】 四川大学 ， 岩土工程， 2002， 硕士

【摘要】 本文第一部分从流固耦合理论出发，以有限元分析为主要研究手段，针对平面模型，计算了基于对库水不同处理方法，坝体的动力响应。表明水可压缩性对动水压力强度和分布具有较大影响。应用在平面波作用下液体-气体-固体动力系统的理论，分析了大坝隔震气幕的力学性态；应用基于理想气体状态方程的气幕隔震的压力有限元模型，对模型气幕的隔震效果进行了研究。 计算结果表明气幕对大坝具有良好的隔震性能，可降低动水压力75％以上。 针对平面模型，用初位移激震分几种工况进行实验。用位移传感器量测同一点的位移时程。动水压力用脉动压力传感器进行测量。在坝面上布置测点，取得测点的动水压力时程分布和沿坝面的分布。与计算结果相比，坝体动力反应的趋势大致相符。在坝面不完全布置气幕的情况下，无论是计算还是实验结果均可说明，坝面中部气室减震效果显著，且气幕减震在坝的中下部体现较明显。模型实验所得气幕隔震后，动水压力降低70％，与计算结果基本符合。证明了理论的正确性。 为了研究高土石坝在大单宽流量下的稳定性，本文第二部分主要对几种不同的土石坝护面材料进行了探讨，根据材料的特性和各自的受力特点，提出选用一种新型的柔性护面材料—橡胶板作为土石坝的防护材料。 采用多普勒激光测速仪对过流断面的流速分布进行了测量，并根据流速分布推求出坝面上橡胶板所受的水流剪应力，和水流对橡胶板的摩阻系数。从而验证了柔性溢洪道的可行性。更多还原

【Abstract】 At the first part of the paper, based on the theory of interaction of fluid-solid, the FEM method is used to analyze the dynamic reaction of the model dam. The results show that the affection of compressible properties of water is large. The mechanical properties of the air cushion are studied theoretically. The FEM air isolation model based on the state equation of ideal gas is used to study the effects of air isolation. The calculation results suggest that air isolation can reduce the hydrodynamic pressure significantly and restrain the dam vibrations during earthquake. The air cushion will reduce hydrodynamic pressure for 75%.Forced vibration tests of the model dam, excited by the initial displacement, measurement have been carried out for several cases. The displacement time history is measured using the displacement sensor. Hydrodynamic pressure is measured with pressure sensors. The measuring points are placed on the model dam. According to the hydrodynamic pressure time history of the points, the distribution of hydrodynamic pressure along the dam is determined. The tendency of the dam dynamic response is basically agree with the calculation results. The hydrodynamic pressure is reduced for 70% with air cushion isolation. The result is basically agreed with the calculations and can verified the theoryFor the stability of earth-rock dams under flood discharge, in the second part of this paper, several kinds of slope-protection materials are studied. According to the material property, a type of new flexible slope-protection material applied to overflow earth-rock dams-rubber panel armoring-is presented. The velocity profiles along the channel section are measured using the Laser Doppler Anemometer. According to the velocity distribution, boundary shear and the coefficient of friction between the flow and rubber panel, is determined. The calculation results verified the feasibility of the flexible spillway.更多还原