【作者】 张斌；

【导师】 陈健云；

【作者基本信息】 大连理工大学 ， 水工结构工程， 2009， 硕士

【摘要】 随着国民经济的快速发展,我国水电能源开发利用进入重要的发展时期。一大批世界级高混凝土坝在我国西南地区开工建设,而这些地区正是高烈度地震频发地区,有的设防地震烈度甚至达到了Ⅸ度。这些高混凝土坝的抗震安全将直接关系到相关地区国民经济的和人民生命财产安全。本文以研究碾压混凝土重力坝的地震破坏形态、破坏机理与抗震措施为目的,从碾压混凝土重力坝坝段动力模型试验入手,结合数值计算研究重力坝的破坏模式与抗震措施,讨论抗震配筋优化问题。为工程设计人员有针对性地采取工程措施进行大坝抗震设计提供参考。具体做了以下五个方面的工作:1.为了模拟实际工程中采用的抗震配筋措施,探索细金属丝在仿真混凝土中的特性。通过模拟配筋的四点弯折试验得到在适筋情况下可以不考虑钢筋与混凝土的粘结滑移效应的结论。在这种情况下,研究配筋量的相似率:采用牛顿第三定律与粘结力相似准则,推导出钢筋有效面积比尺作为相似配筋量的相似率。2.以仿真混凝土为基体,掺入粘土或橡胶颗粒来增强仿真材料塑性,探讨高塑性的仿真材料的物理特性。为在不完全几何相似的情况下的模型大变形反应和塑性混凝土的相似材料两方面研究提供了一定的参考。3.采用水下电液伺服地震模拟系统对阿海碾压混凝土重力坝典型坝段进行无抗震措施与局部模拟配筋抗震措施模型试验。分析厂房坝段动力破坏形式,研究局部配筋对地震荷载作用下对挡水与溢流坝段破坏动力非线性反应影响。4.利用ABAQUS平台对阿海碾压混凝土重力坝进行有限元分析。采用弹塑性损伤本构模拟混凝土非线性,同时依据模型试验配筋量相似比率建立局部抗震配筋的坝体原型有限元模型,进行了挡水坝段的抗震配筋影响分析。5.优化配筋方案计算分析不同形式的局部抗震配筋对挡水坝段的动力非线性反应的影响,具体从动力放大倍数、极值应力、极值位移、损伤发展、不可恢复应变与整体耗能几方面进行探讨。同时给出线弹性情况下规范配筋量与之进行对比。更多还原

【Abstract】 With the rapid development of national economy, the exploitation and utilization of water power is stepped the key development stage. A batch of dams, word-class high concrete dams, have being constructed in southwest of China. However, the place is a high intensity seismic zone. Specially, the adopted design level of earthquake ground motion reaches to nine degree at some dam sites. It is very significant that aseismic safety of dams for industrial and agricultural production and the safety of the people’s life and property in the large region of downstream. In order to study the dynamic destruction mechanism and aseismic measures of concrete gravity dam in earthquake, the dynamic shaking table model tests and finite element analysis were adopted to investigate failure mode and aseismic measures in this paper. The optimization design of aseismic reinforcement at some key parts was also discussed. Test results can provide references for engineering design. The main contents of the paper are five parts as follows:1. As stainless steel wires were embedded in emulation concrete, properties of them were studied for the purpose of simulation of reinforced concrete. Base on four point bend tests, neglction of bond-slip was concluded at model tests. With this hypothesis, similarity of quantity of steel was elicited to employ effective area scale of steel bars. The derivation process was applied with Newton’s third law and similarity of cohesive force.2. High plastic emulation materials were made by means of using emulation concrete as basal body and added clay or added crushed rubbers. And physical characteristics of materials were investigated. The test results can be useful for study of model’s large deformation and plastic strain in view of incomplete geometric similarity.3. Model test of Ahai RCC dam was carried out with electric-hydraulic underwater seismic simulated servo system. Model test was divided into two sections, models without aseismic measures and models with aseismic reinforced concrete at some key parts. And then the failure mode of Ahai house-dam and effect of aseismic reinforced concrete for water retaining dam section were studied.4. Finite element analysis of Ahai RCC dam was conducted with software of ABAQUS. The plastic damage model was applied as concrete nonlinear constitutive relation. Base on the similarity of aseismic steel and quantity of aseismic wire in test, the finite model with rebar was created. The effect of rebar in water retaining dam section was analyzed. 5. Optimization design of reinforcement at some key parts of dam had been made through numerical calculation of nonlinear reaction under design input of ground motion. Concretely, the research contents included dynamic amplification coefficients、extreme values of stress、extreme values of strain、development of damage、variation of irrecoverable strain and dissipation energy. The paper also investigated aseismic bars under the circumstances of linear elastic constitutive relationship.更多还原