温湿条件下闸墩结构力学行为分析

发布时间：2018-09-01 06:28

【摘要】：水闸是平原地区常见的水工建筑物，根据工程实例可知，闸墩部位易出现裂缝的问题，水闸闸墩裂缝的产生主要由于墩体内外温差、混凝土的干缩、自生体积变形和外部约束引起，且各种原因都有一系列的影响因素。该问题长期以来困扰着工程设计人员，且一直未能得到很好的解决。闸墩裂缝的出现给水闸工程带来了多方面不同程度的危害，因此也越来越受到学术界的重视。闸墩混凝土在施工期由于水泥水化热作用，温度应力在应力中占有较大比重，是混凝土结构裂缝产生的重要原因之一；且水闸在水工结构工程中属薄壁结构，与大坝等大体积混凝土相比，薄壁结构混凝土的表面积与体积之比要大得多，水分散发速度和散发量相对快和大，干缩变形突出。综上可知，对闸墩混凝土结构在温湿度条件下的力学行为展开一项专门研究是非常有必要的。本文就水闸中常见的裂缝问题进行了较深入的研究。分析了闸墩混凝土结构在温湿度条件下的力学行为及裂缝成因；考虑水闸闸墩混凝土在施工期弹性模量、徐变度随时间的变化以及外界气温变化，，针对施工期间可能发生的较为不利的寒潮等情况，分别进行了闸墩温度场和温度应力的全过程耦合仿真分析。考虑闸墩施工过程中的外界湿度条件，模拟闸墩实际施工过程中的湿度场分布情况，对施工期闸墩干缩应力进行全过程仿真分析。利用温湿耦合方法，实现了对闸墩温度干缩应力的模拟，对温湿耦合条件下的闸墩结构力学行为进行深入研究，并根据模拟结果对水闸防裂设计和施工提出了一些建议。
[Abstract]:Sluice gate is a common hydraulic structure in plain area. According to the engineering examples, cracks are easy to appear in the piers. The cracks of sluice piers are mainly caused by the difference in temperature inside and outside of the piers and the shrinkage of concrete. Autogenous volume deformation and external constraints are caused by a series of factors. This problem has been puzzling engineers for a long time, and has not been well solved. The emergence of pier cracks has brought many kinds of hazards to the sluice engineering, so it has been paid more and more attention by academic circles. Due to the hydration heat of cement during the construction period, the temperature stress occupies a large proportion of the stress, which is one of the important reasons for the cracks of concrete structure, and the sluice is a thin-walled structure in the hydraulic structure engineering. Compared with large concrete such as dams, the ratio of surface area to volume of thin-walled concrete is much larger, the velocity and amount of moisture emission are relatively fast and large, and the shrinkage deformation is prominent. In summary, it is necessary to conduct a special study on the mechanical behavior of pier concrete structure under the condition of temperature and humidity. In this paper, the common cracks in the sluice are studied in depth. The mechanical behavior of concrete structure of sluice piers under the condition of temperature and humidity and the causes of cracks are analyzed, and the changes of elastic modulus, creep degree with time and temperature outside of sluice pier concrete during construction are considered. In view of the unfavorable cold wave which may occur during the construction period, the coupled simulation of the temperature field and the temperature stress of the pier is carried out respectively. Considering the external humidity conditions during the construction of the pier and simulating the distribution of the humidity field during the actual construction of the pier, the dry shrinkage stress of the pier during the construction period is simulated and analyzed. By using the coupled method of temperature and humidity, the dry shrinkage stress of the pier is simulated, the mechanical behavior of the pier structure under the coupled temperature and humidity conditions is deeply studied, and some suggestions for the design and construction of the sluice crack prevention are put forward according to the simulation results.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV662.2;TV312

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