碾压混凝土重力坝动力稳定非线性分析

发布时间：2018-06-05 14:49

本文选题：重力坝 + 非线性　；参考：《大连理工大学》2014年硕士论文

【摘要】：随着社会的发展和经济的进步,我国对能源的需求愈加迫切。我国是世界水利大国,外加水电具有低碳、清洁能源等优势,水电事业具有广阔的开发前景。目前在我国西南高烈度地区在建和规划了一大批百米级大坝和超高的大坝,混凝土重力坝的抗震研究工作尤为重要,因此本文结合某碾压混凝土重力坝工程,运用ANSYS和ABAQUS有限元程序对重力坝的地震响应以及抗震计算工作做了如下研究： 1、针对地基边界的选取,选取了无质量地基刚性约束、具有刚度特性和阻尼特性的粘弹性边界、有限元-无限元耦合三种不同的边界条件。针对不同的边界条件进行静力和动力的算例验证,通过与弹性力学理论解和相关波动理论来验证程序施加边界条件的正确性。 2、在线弹性模型的基础上,采用三种不同的边界条件,计算碾压混凝土重力坝工程实例在地震荷载作用下的时程响应,并从应力、位移及动力稳定三个方面评价了不同边界条件的响应特性及适用边界条件,计算结果表明无质量地基刚性约束边界的动响应较大,粘弹性边界和无限元边界对地震波反射的吸能效果较好,且计算精度相当,但是无限元边界在计算时间上比较节省,计算效率较高。 3、选用无限元-有限元耦合的模型,综合考虑混凝土材料以及岩土材料的非线性特性,采用ABAQUS提供的粘聚力模型(cohesive)模拟碾压混凝土层间以及地基中软弱结构面的接触问题。对比线弹性模型,从应力响应、位移响应以及抗滑稳定性角度研究考虑材料非线性和接触之后的结构动力响应。 4、应用有限元方法计算的应力结果,分别采用规范推荐的分项系数法和强度折减法对碾压混凝土层间抗滑稳定以及深层抗滑稳定的安全性进行分析评价。研究表明,针对双滑面整体弯矩法计算所得的安全系数要比等K法略大；降强法得到的安全系数与分项系数法比较接近。建议综合考虑各方法的计算结果进行坝体和坝基的动力失稳评判。
[Abstract]:With the development of society and the progress of economy, the demand for energy in our country is more and more urgent. China is a big water conservancy country in the world, and hydropower has the advantages of low carbon, clean energy and so on. At present, a large number of 100-meter dams and super-high dams are under construction and planning in the high intensity area of southwest China. The seismic research work of concrete gravity dams is particularly important, so this paper combines with a roller compacted concrete gravity dam project. Using ANSYS and ABAQUS finite element program, the earthquake response and seismic calculation of gravity dam are studied as follows: 1. According to the selection of foundation boundary, three kinds of boundary conditions are selected, which are rigid constraint, viscoelastic boundary with stiffness and damping characteristics, and the coupling of finite element and infinite element. Examples of static and dynamic tests are given for different boundary conditions. The correctness of the boundary conditions imposed by the program is verified by the theoretical solution of elastic mechanics and the related wave theory. 2. On the basis of the online elastic model, three different boundary conditions are used to calculate the time-history response of the RCC gravity dam project under earthquake load. The response characteristics and applicable boundary conditions of different boundary conditions are evaluated from three aspects of displacement and dynamic stability. The results show that the dynamic response of rigid constrained boundary is large. The viscoelastic boundary and infinite element boundary have good energy absorption effect on seismic wave reflection, and the calculation accuracy is equal, but the infinite element boundary is less in calculation time and higher in efficiency. 3. The coupling model of infinite element and finite element is used to simulate the contact problem of soft structural plane between roller compacted concrete layers and foundation by considering the nonlinear characteristics of concrete and geotechnical materials. The cohesive force model provided by ABAQUS is used to simulate the contact between RCC layers and soft structures in foundation. Compared with the linear elastic model, the dynamic response of the structure considering material nonlinearity and contact is studied from the stress response, displacement response and anti-slip stability. 4. The stress results calculated by finite element method are used to analyze and evaluate the safety of roller compacted concrete (RCC) interlayer stability and deep layer anti-sliding stability by the method of subdivision coefficient and strength reduction recommended by the code. The results show that the safety factor calculated by the integral bending moment method for double sliding surfaces is slightly larger than that by the equal K method, and the safety factor obtained by the strength reduction method is close to that obtained by the partial factor method. It is suggested that the dynamic instability of dam body and foundation should be evaluated by considering the calculation results of each method.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV642;TV312

【参考文献】