【作者】 管军华；

【导师】 马震岳；

【作者基本信息】 大连理工大学 ， 水利水电工程， 2009， 硕士

【摘要】 随着时间的推移,混凝土大坝老化和损伤在老坝中不同程度地存在,主要问题包括混凝土材料强度降低,渗漏增大,存在裂缝并扩展,耐久性和安全性偏低,与之相对应,关于老混凝土坝修复加固的系统性研究,一直是国内外水工结构领域理论研究的热点。本文基于一种新的老坝再生技术(坝内开槽置换新混凝土方案)为基础进行研究,以利于工程实际问题的解决。本文以我国东北某带缝的老化混凝土重力坝为背景,结合坝内开槽置换混凝土加固方案,应用ANSYS自带的APDL语言,编写施工仿真程序,针对实际带缝坝体再生施工时可能出现的坝体安全问题进行分析。对于坝体内开槽施工,开挖混凝土破坏坝体内原有的应力分布,新浇筑混凝土产生的水化热也将使坝体的温度场发生改变,因此,对坝体内开槽置换混凝土方案做出评价是很有意义的。本论文对坝体纵缝的影响作了详细分析,并对该加固方案施工过程作了详细模拟。在温度计算中将考虑坝体纵缝、坝体不同材料分区、防渗墙分层开挖和浇筑施工方式、新浇筑防渗墙混凝土热学参数随龄期变化、施工工期等因素的影响,从而对该方案的可行性进行评价。研究表明,由于施工范围相对于整个坝体较小,新浇混凝土对坝体整体温度场影响不大,但坝内施工导致坝体内部温度和应力都有一定程度上的变化。依托老化混凝土重力坝创新性全面修复加固方案——坝体内置换混凝土防渗墙加固方案,本文的研究成果不仅为该实际加固工程的设计和施工提供理论依据,为方案施工期的坝体结构安全性评价提供参考,而且明确了该技术方案的可行性和所需采取的安全措施,为老坝修复加固方案的论证和实施提供了理论支撑。更多还原

【Abstract】 With the time going on,the concrete dams grow aging and then there are many problems of the dam such as falling intensity of the concrete,seeping,cracking,the lower security and durability.So the systemic study on reinforcement of the old dams is popular in the worldwide field of hydraulic structure all along.At present,a new technique,forming inner wall to prevent seeping by replacing dam concrete,is introduced to rehabilitate old dams, based on which this paper discuss the problems above.Taking a concrete gravity dam in northeast of china for example,this paper discusses and analyzes the systematic safety problem for dam rehabilitation.During the analysis, general software,ANSYS,which has its own program,APDL,is used to model the process of construction.For the construction,the digging of the concrete destroys the field in the dam, and the hydration heat temperature rise of the fresh concrete also damages the field in the dam. Therefore it is significant to evaluate the new technique,forming inner wall to prevent seeping by replacing dam concrete.This paper analyzes in very great detail the longitudinal joints’ influence upon the dam, and simulates the process of construction in detail.In the calculatian of temperature,some factors are taken into consideration including the longitudinal joints,the materials of different partitions,the different digging and pouting process of the concrete,the changing of the thermodynamic parameters,the time limit for the project.The result could be summarized as follows:because the area is relatively narrow,so the impact of the fresh concrete is not big, but the field of the temperature and stress in the dam is variational to a certain extent.Based on this rehabilitation technique of aging concrete dam,the results of this paper could be used as a theory not only to this engineering but also to other similar projects since it can predict the systematic safety of dam construction and provide effective reference for technique of construction.更多还原