【作者】 范书立；

【导师】 林皋； 陈健云；

【作者基本信息】 大连理工大学 ， 结构工程， 2007， 博士

【摘要】 随着西部大开发战略的实施，一批高坝在我国西南部正要或将要开工建设，这些工程库容达数十亿到数百亿立方米，并且大部分处于强烈地震活动区，若发生破坏将带来严重的后果。本文以研究混凝土重力坝的地震破坏形态、破坏机理为目的，从混凝土重力坝的振动台动力模型破坏试验入手，结合数值计算研究了混凝土重力坝的地震作用下，从损伤到破坏的全过程，并探讨了混凝土重力坝的可能破坏模式及可靠性，为工程设计人员有针对性地采取工程措施进行重力坝抗震设计提供参考。主要内容如下：进行混凝土坝大缩尺动力模型试验时，研制出满足相似要求的模型混凝土材料成为问题的关键。为了得到模型试验所需要的理想仿真混凝土材料，在电子材料试验机上对大连理工大学研制出的仿真混凝土材料的力学性能和各种参数进行了较详细的研究。对仿真混凝土进行了单向应力状态下的拉、压试验，系统地研究了龄期、配比、养护温度等对仿真混凝土强度及变形特性的影响。结合原型混凝土的力学特性，研究了仿真混凝土的拉、压本构关系。进行了仿真混凝土的抗剪试验、断裂破坏试验，测试了仿真混凝土材料的抗剪强度及断裂韧度。并研究了应变速率对仿真混凝土抗拉、抗压性能的影响，探讨了动荷载下仿真混凝土的破坏机理。采用方程分析法，详细推导了弹性动力模型试验的常用的相似准则，研究各自的前提条件以及各相似律之间的转换关系。在此基础上针对仿真混凝土材料与普通混凝土归一化后应力-应变关系的一致性，探讨了非线性动力模型破坏试验相似条件，并在放宽应变比尺要求的前提下，推导了非线性动力模型试验的相似律，认为对于仿真混凝土模型试验材料，只要保证仿真混凝土与普通混凝土的应力-应变关系的一致性，动力模型破坏试验可以在一定程度上反映原型混凝土坝在强震下的非线性反映、极限承载力以及最终的破坏形态。通过振动台动力模型破坏试验和数值计算两种途径，研究了混凝土重力坝的破坏过程及可能破坏模式，分析了混凝土重力坝的动力破坏机制。采用仿真混凝土材料，在大型水下振动台上进行动力模型破坏试验，研究混凝土重力坝在地震过程中的非线性动力特性，以及不同坝段的地震破坏形态，并对不同地震动峰值下大坝整体的损伤进行了探讨。采用弹塑性损伤模型模拟了混凝土重力坝的损伤破坏过程，分析了重力坝的损伤破坏影响因素。并通过对有限元法中不同水荷载施加方式对计算结果影响的分析比较，探讨了各自的适用性。采用平面渗流理论，分析了渗透压力对坝体变形、应力分布及抗滑稳定的影响。通过结构-地基的动力相互作用分析公式的推导，详细阐明了考虑无限地基影响的动力相互作用分析中无质量地基的概念和应用范围，提出了一种考虑结构-地基动力相互作用的简化分析方法。考虑混凝土材料、岩体材料和地震动的变异性，采用响应面法得到模拟重力坝极限状态方程的二次多项式，利用可靠度的有限步长法计算体系的可靠度。结合适应谱Push-over方法，改进了拟静力法中重力坝地震惯性力动态分布系数，将其用于重力坝动力可靠度计算。通过对强震区混凝土重力坝的极限承载能力以及地震作用下可能失效路径对基本功能目标影响分析，研究不同失效路径下重力坝体系的可靠度影响因素，分析了对应于坝体失效、地基失效、层面稳定以及闸门启闭的每种失效模式的失效概率和重力坝的体系可靠度，并用系统可靠度理论研究了地震东对整个混凝土重力坝体系的失效概率及可靠度影响。更多还原

【Abstract】 With implementing of the West Grand Development Strategy, one batch of high concrete dam is building or will be constructed in southwest in China. The reservoir capacities of these projects reach several billion cubic meters, and most of these projects build in strong earthquake region. Once the dams are failure, society and people will suffer from the disaster to economy development, people’s life and property. In order to study the dynamic destruction mechanism of concrete gravity dam in earthquake, the dynamic shaking table model experiments and FEM-based numerical calculations were adopted to research the whole process of concrete gravity dam from damage to failure in this paper. The failure mode and reliability of gravity dam was also discussed. The results offer important reference to engineering designers and. anti-seismic design. The major contributions are summarized as follows:In large scale model shaking table test of concrete gravity dam, How to develop a type of similar model material to meet the similar requirements have been a noticeable focus. In order to obtain a ideal material for large scale model test, this dissertation investigated the features of low strengthen-emulation concrete materials including their uniaxial proportions in tensile and compressive loadings, dynamic natures. The deformation and relationship of concrete under tensive and compressive loading were researched referring to mechanical properties of common concrete. Test on shear strength and fracture behavior of emulation concrete were also performed. The effect of strain rate on emulation concrete tension and compressive properties was examined and the failure mechanism of emulation concrete under dynamic load was analyzed.Similarity theory is the premise of the large scale model experiments. The basic requirements and similarity criteria of dynamic model test were derived in detail based on the equations analysis methods. The prerequisites and relationship of each similarity rules were researched. On this basis, similarity conditions of seismic rupture model test were discussed. On the condition of relaxing strain scale, the similarity theory of nonlinear dynamic model test was derived.The failure process and failure mode of concrete gravity dam were studied using seismic rupture model test and simulation calculation and the failure mechanism of gravity dam was discussed. Emulation concrete material was used to study the gravity dam failure process and nonlinear dynamic response in earthquake by shaking table tests. The factors influencing the damage of dam were analyzed through simulation on the failure process of concrete gravity dam by using elasto-plastic damage constitutive relations model for concrete. Aiming at how to simulate the uplift pressure of the interface between dam and foundation in the stress and stability analysis of dam with Finite Element Method, different numerical simulation methods of imposing uplift pressure were analyzed. By comparing the influences on the deformation, stress distribution and stability of dam foundation rock, their applied range and limitation of are indicated respectively for specific application purpose. At same time, the influences of dam seepage fields on the dam deformation were discussed based on spatial seepage flow theory. Detailed formula for the soil-structure dynamic interaction analysis is derived, the concept and the application criteria of mass-less base model for soil-structure dynamic interaction analysis is clarified. A simplified method was presented on engineering design for analysis of dynamic soil-structure interaction.Taking the variability of material parameters and earthquake into account, a quadratic polynomial fitted by using response surface method was used to simulate the limit state equation of concrete gravity dam. The reliability index was calculated by a finite iteration step method. The distribution of effective earthquake forces was ameliorated according to adaptive spectra-based Push-over procedure and used in calculating the gravity dam’s probability. The influence of different failure path on the reliability of concrete gravity dam was studied by analyzing the dam’s ultimate load bearing capacity. Probable seismic failure paths and failure modes corresponding to limit load state and normal operation state were analyzed. The failure probabilities for the different failure modes corresponding to dam, rock, sliding of roller compacted layer and floor were further analyzed. And based on system reliability theory, the dynamic system failure probability and reliability index of concrete gravity dam were obtained in terms of the correlated and non-correlated failure modes. The results indicate that the reliability levels have relation to various failure paths. The corporate influence of the different failure path on system’s reliability of pile foundations should be considered.更多还原