土石坝施工应力与沉降分析

发布时间：2018-01-02 11:29

本文关键词：土石坝施工应力与沉降分析　出处：《华北水利水电大学》2016年硕士论文　论文类型：学位论文

【摘要】：截至2006年,中国已建成各类水库8.7万多座。绝大多数水库修建于二十世纪60至70年代,期间受社会因素和科技发展的制约,由于施工技术标准不完备,造成大多数土坝设计标准偏低和施工质量普遍较差,久而久之坝体现状老化严重,大大小小事故屡有发生,部分水库存在安全隐患。据统计,目前全国有各种病险水库约3.7万座,土石坝占95%以上。造成土石坝险情的主要因素有渗漏、稳定、裂缝等。目前对渗流及稳定等方面的计算,已日益趋于成熟,但对施工过程中由于土体不均匀变形引起的土石坝沉降问题的研究还应进行完善。选择适当的计算方法的和本构模型是影响计算成果准确与否的关键。为此本文介绍了几种计算分析方法和本构模型,因有限单元法计算相对准确、高效;邓肯-张E-B模型能够模拟土体绝大部分特性,计算结果精度满足要求,最终选定有限元法和邓肯张本构模型。本文运用ANSYS软件,利用其二次开发功能APDL语言进行编程,并添加邓肯-张E-B模型宏命令,利用“生死单元法”对土石坝分层填筑模拟施工,并编制了后处理程序对位移进行修正。具体过程如下:(1)建立了100m的均质坝模型模拟其施工过程,输出应力应变云图,分析其结果符合土石坝的一般规律,具有一定的准确性。(2)结合相关文献具体土石坝案例,模拟其分层加载过程,并对分层加载结果进行分析,得出结果应力分布符合土石坝的一般规律,可以用于工程实践中。为此本文将以涧里水库除险加固工程为例,建立了大坝施工过程的三维有限元仿真分析模型,对土石坝在施工期采用分级填筑的方法,利用邓肯-张E-B模型,进行仿真模拟,在计算时假定土石坝的筑坝材料在施工期的变形在分层填筑过程中已经完成,坝体填土、反滤料、坝基砂卵石按均质各向同性考虑,建立了涧里水库土石坝变形与荷载之间的对应关系,对土石坝会产生沉降、横向的位移进行分析,判断裂缝产生位置,弄清哪里是薄弱环节,并采取相应的处理措施。计算结果可为工程除险加固后的大坝安全监测与管理提供重要参考。
[Abstract]:As of 2006, Chinese has built all kinds of more than 8.7 seats. Most of the reservoir reservoir was built in twentieth Century 60 to 70s, during the period of restricted by social factors and the development of science and technology, the technical standard of the construction is not complete, causing most of earth dam design standard is low and the construction quality is generally poor, in the course of time reflects the serious aging dam shape, large and small accidents happen repeatedly part of the reservoir, there are security risks. According to statistics, there are about 37 thousand kinds of reservoirs, dam accounted for more than 95%. The main factors causing the danger of dam leakage, stable crack. The seepage and stability calculation, has become increasingly mature, but in the construction process because of the the uneven deformation of earth rock dam settlement problems should also be perfected. Select the appropriate calculation method and constitutive model is accurate calculation results and not. Key. This paper introduces the calculation method and several constitutive models, the finite element method for calculating relative accurate and efficient; Duncan Chang E-B model can simulate most of the soil properties, the results meet the requirement, the selected finite element method and Duncan model. Finally this paper uses ANSYS software, programmed by using the second the development of APDL language, and add the Duncan Chang E-B model using macro command, "to simulate the construction of earth rockfill dam filling the birth death element method, and the preparation of the postprocessing procedure to correct the displacement. The specific process is as follows: (1) the establishment of a homogeneous dam 100m model to simulate the construction process, the output of stress and strain the results accord with the general rule, analysis of earth rockfill dam, has certain accuracy. (2) combined with the literature concrete dam case, simulate the layered loading process, and the layered loading results are analyzed, The results of stress distribution accords with the general law of earth rockfill dam, can be used in engineering practice. This paper will take the Jianli reservoir reinforcement project as an example, the establishment of a three-dimensional finite element simulation of dam construction process analysis model, method of earth dam by grading embankment during construction period, the Duncan Chang E-B model of the simulation, material assumed in the calculation of earth rockfill dam has been completed in layered filling process in deformation during the construction of dam filling, filter material, sand and gravel foundation is considered as homogeneous and isotropic, establishes the corresponding relationship between Jianli reservoir dam deformation and load, will produce the settlement of earth rock dam, analysis the horizontal displacement, crack position judgment, find out where is the weak link, and take corresponding measures. The results can be strengthened for dam safety monitoring project and after measurement and management Important reference.

【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV641

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