基于ABAQUS的高混凝土坝的动力损伤分析

发布时间：2018-10-09 13:59

【摘要】：围绕国家能源战略部署,一批高混凝土拱坝和高混凝土重力坝即将在水能资源充沛的云南、四川地区建设。该地区处于地震多发区,高混凝土坝的抗震安全评价及灾变过程研究刻不容缓。本文的研究目的是得到拱坝和重力坝两种常见的混凝土坝型在地震荷载作用下的动力响应,并且指出拉伸损伤发生的部位和裂缝的发展情况。研究方法基于有限元软件ABAQUS内嵌的混凝土损伤塑性模型,对国内某拱坝及重力坝在强烈地震作用下的动力响应进行了数值模拟,得到了地震全过程拱坝及重力坝拉损伤分布和典型单元的损伤发展时程,给出了拱坝及重力坝的损伤发生、发展过程,并指出了两种坝型的抗震薄弱部位,为高混凝土坝抗震安全评价提供了一种分析途径。具体主要内容有： (1)简要介绍论文所用到的理论知识,即有限元基本原理、动力方程的建立以及损伤力学的基本概念。介绍了ABAQUS内嵌的混凝土损伤塑性模型及该模型所用到的输入参数。 (2)以国内某拱坝为工程背景剖分形成三维有限元模型,对其进行模态分析,提取振型及拱坝固有频率,开展线弹性和非线性两种模型下自重和地震作用组合工况的数值计算,整理得到顶拱及拱冠梁处的各方向加速度、各方向位移及第一主应力包络曲线,并对比了两种本构模型得到的结果变量的包络图。提取地震作用下高拱坝的典型单元的损伤发展时程,从上下游面、垂直z轴切面、垂直x轴切面三个角度给出了坝体最终的损伤分布情况,探讨了高拱坝在地震作用下的裂缝扩展过程。 (3)建立西部某重力坝的有限元模型,进行模态分析,开展线弹性和非线性两种模型下自重和地震作用组合工况的数值计算,整理得到上下游折坡点、坝踵及坝趾等关键位置处的各方向加速度、位移及第一主应力时程曲线,并对比了两种本构模型得到的结果变量。从上下游视角、垂直y轴水平切面、垂直z轴竖直切面三个角度给出了坝体最终的损伤分布情况,探讨了高重力坝在地震作用下的裂缝扩展过程,并与之前的模型试验进行了对比。
[Abstract]:According to the national energy strategy, a number of high concrete arch dams and high concrete gravity dams will be built in Yunnan and Sichuan regions with abundant hydro energy resources. This area is in the earthquake prone area. It is urgent to study the seismic safety evaluation and catastrophic process of high concrete dam. The purpose of this paper is to obtain the dynamic response of two common concrete dam types, arch dam and gravity dam, under earthquake load, and to point out the location of tensile damage and the development of cracks. Based on the damage plastic model of concrete embedded in finite element software ABAQUS, the dynamic response of an arch dam and gravity dam under strong earthquake is numerically simulated. The tensile damage distribution of arch dam and gravity dam during earthquake and the damage development history of typical elements are obtained. The damage occurrence and development process of arch dam and gravity dam are given, and the weak seismic sites of two types of dam are pointed out. It provides an analytical approach for seismic safety evaluation of high concrete dams. The main contents are as follows: (1) A brief introduction of the theoretical knowledge used in the paper, namely, the basic principles of finite element, the establishment of dynamic equations and the basic concepts of damage mechanics. The damage plastic model of concrete embedded in ABAQUS and the input parameters used in the model are introduced. (2) taking an arch dam in China as the engineering background, a three-dimensional finite element model is formed, and the modal analysis is carried out, the natural frequencies of the arch dam are extracted, and the numerical calculation of the combined working conditions of deadweight and seismic action under the linear elastic and nonlinear models is carried out. The envelope curves of acceleration, displacement and principal stress in each direction of the arch and arch crown beam are obtained, and the envelope diagrams of the result variables obtained by the two constitutive models are compared. The damage development time history of typical elements of high arch dam under earthquake action is extracted. The final damage distribution of the dam body is given from three angles: upstream and downstream plane, vertical z axis section plane and vertical x axis section plane. The crack propagation process of high arch dam under earthquake is discussed. (3) the finite element model of a gravity dam in the west of China is established, the modal analysis is carried out, and the numerical calculation of the combined working conditions of deadweight and seismic action under the linear elastic and nonlinear models is carried out, and the upstream and downstream break slope points are obtained. The time history curves of acceleration displacement and first principal stress at the key positions such as dam heel and dam toe are compared and the result variables obtained by two constitutive models are compared. The ultimate damage distribution of dam body is given from three angles of view, vertical y axis horizontal section and vertical z axis vertical cut plane, and the crack propagation process of high gravity dam under earthquake is discussed. And compared with the previous model test.
【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

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