【作者】 周兵；

【导师】 金峰；

【作者基本信息】 清华大学 ， 水利工程， 2008， 硕士

【摘要】 拱坝抗震性能研究是当前坝工领域的关键课题之一。本论文的采用离心模型试验方法,研究拱坝-坝肩系统的动力抗滑稳定,以及拱坝在动力荷载作用下的破坏机理问题。研究的主要方法是通过模型试验测定拱坝模型的动力反应,然后将试验成果与离散元程序3DEC及有限元程序ABAQUS计算结果进行对比验证。论文工作内容如下:1.根据相似理论,推导出了结构离心模型动力试验的相似关系;按照相似关系进行模型设计和制作。采用清华大学水工结构实验室多年来在拱坝模型试验中总结出来的重晶石膨润土混合料,通过一系列材料试验,得出合适的材料配比,并制作出拱坝模型。2.设计制作了测量缝开度的试验仪器——测缝计,从原理上推导了缝面开度与电桥电压输出之间的线性关系,并实际加工制作了一批测缝计,在静、动态标定的基础上应用于实际动态试验。根据标定结果及试验量测数据可以发现,测缝计具有较好的性能。3.通过离心动力试验研究拱坝-坝肩离心模型的动力响应,采用脉冲激励和白噪声激励的方法获得模型的共振频率;采用谐波激振得出模型的动力反应,包括加速度、应变和缝开度反应,研究拱坝-坝肩体系的动力响应规律和破坏机理。4.通过脆性材料制作的模型拱坝的离心动力试验,得到了模型拱坝的线弹性动力反应,得到了结构从完整到破坏的全过程,揭示了模型拱坝的动力反应特性和破坏机理;试验结果同时表明,离心模型动力试验对于研究拱坝-坝肩体系的静、动力稳定是一个有效的手段,全部相似关系的满足以及试验过程中的多种加载手段使其相对于一般的振动台试验更加具有优势。5.采用数值计算研究模型的频率特性和谐波激振反应,并与试验结果进行比较分析,对离心模型试验结果进行了验证,同时检验了离散元数值计算方法的合理性。更多还原

【Abstract】 Research on earthquake behavior of arch dams is one of the key issues in dam engineering. This thesis carried out a series of dynamic centrifuge modeling experiment, studying on the arch dam-abutment seismic stability, and the seismic failure of arch dams under dynamic loads. The research is carried out through model tests on the centrifuge shaking table for dynamic response of the dam model, and then compared with the distinct element method using 3DEC and the finite element analysis using ABAQUS for verification. The main contents are as follows:1. The similarity relationship of dynamic centrifuge test is derived out on the basis of similarity theory. Model is designed and made based on the similarity relationship. The material of the dam model is a mixture of barite and bentonite, which was most commonly used by the hydraulic laboratory for the modeling of arch dams. A series of material tests are carried out to find the appropriate ratio of combination, and then the dam model is made.2. A gap measure is designed and made to measure the displacement of the gap opening. The liner relationship between the opening of the gap and the voltage of the electric bridge is first derived out based on analysis, then several gap measures are processed and calibrated. It is found that the gap measure behaves well in dynamic test and gives reasonable results.3. The dynamic response of arch dam-abutment is obtained through dynamic centrifuge test. The impulse load and white-noise load is applied to acquire the frequency of the dam model, and harmonic load is applied to acquire the dynamic response of the model, including acceleration, strain and the opening of the discontinuity. Then the disciplines of dynamic reaction and the mechanism of damage of the arch dam are studied.4. Through the dynamic centrifuge test carried on the dam model made of brittle material, both the elastic dynamic response and the whole damage process of the dam are obtained. These results reveal the characteristic of dynamic response characteristic and the damage mechanism of the arch dam. The research results show that, the dynamic centrifuge test is a very useful method for study on the arch dam-abutment system. The ability of satisfying all similarity relationship and all kinds of loading technique makes the dynamic centrifuge test more powerful than the common shaking table test.5. Numerical solution is applied to calculate the frequency characteristic and the harmonic response of the model, and then compared with the experiment results. These researches verify the correctness of dynamic centrifuge test, and show the rationality of distinct element method on the study of arch dam-abutment system.更多还原