空腹重力坝体型优化及施工期温度场应力场仿真分析
发布时间：2018-10-12 09:31
【摘要】：空腹重力坝因其具有减小扬压力、降低混凝土工程量、利于施工期散热等优点被国内外广泛采用。然而,该坝型的相关研究仍有不足之处。首先,空腹重力坝的优化设计仍处在方案比选阶段,有进一步优化的空间;其次,其便于散热的特点始终未得到重视,施工过程仿真分析也一直处于空白。而近年来,碾压混凝土的应用越来越普遍,这种施工技术应用于空腹重力坝已成为必然趋势。所以本文以碾压混凝土空腹重力坝作为研究对象,借助ANSYS软件平台,综合考虑温度、碾压混凝土施工特点等影响因素。一方面提出了空腹重力坝的最优结构形式,另一方面通过施工过程热-应力耦合场仿真分析,探索了利用空腹散热的实际效果。论文共分为5个章节,从理论到实践展开研究论述。第一章为绪论,主要对论文研究背景、研究意义、研究内容、研究方法、研究框架进行整合。第二章为仿真分析理论综述。第三章基于空腹重力坝复杂多样的腹孔形式,建立能够完整表达各典型断面的优化数学模型,借助ANSYS优化模块对腹孔结构各参数进行一次性优化,确定最优的断面类型和结构尺寸;第四章基于优化断面进行施工过程模拟,耦合温度与应力场,以相同条件下实体重力坝作为参照,比较了空腹重力坝相比实体重力坝的散热效果,得到了施工期不同空腹温度条件下坝体温度场变化规律;第五章为结论,对本文研究成果进行提炼总结。主要成果如下:(1)应用ANSYS优化模块对空腹重力坝典型断面(城门洞型、扇形、上下游斜墙均向上游倾斜型)进行优化。针对空腹重力坝与坝基接触面积小且受温度影响较大的特点,在优化过程中,采用热固耦合法和接触单元法分析温度荷载及坝体抗滑稳定问题。结果表明,上下游斜墙均向上游倾斜型的布局使空腹走向与坝体内部合力方向相同,从而显著的改善了空腹周围的应力条件;且由于空腹重力坝与基岩面的接触面积较小,寻优过程中不宜减小坝底长度,应将增大空腹高度作为减小工程量的主要手段。经优化,断面面积减少约13.6%,优化断面上下游斜墙与水平面夹角72~76度。以相同的优化过程,设置5种类型的基岩参数,得到不同坝基条件下优化断面的控制条件及变化规律,为不同地质条件下的坝体断面尺寸比选提供参考。在优化结果的基础上,将空腔替换为填渣开展进一步的优化,结果表明:填渣结构不仅能够为施工提供极大地便利,其对坝体抗滑稳定状态的提升作用可以使空腹重力坝优化断面面积进一步减小。(2)根据实际工程资料,对采用优化后截面的坝体进行施工全过程仿真计算,综合考虑外界气温和坝体分层等因素,运用有限元数值分析法模拟施工过程中温度场的变化。在计算结果的基础上,以控制空腹内温度作为温控措施,设置不同方案,进行仿真计算,分析各方案间的差别及对坝体的影响程度。结果表明,空腹重力坝施工完成时内部最高温度28.88度,相比实体重力坝下降5.56度,内外温差降低约40%。完建期实体坝最大拉应力0.613Mpa,空腹坝0.354Mpa,下降0.259Mpa。空腹坝由于散热性能好,产生的内部温升低,且与基岩接触面积较小,建设期的温度应力状态较实体重力坝更为理想。但空腹重力坝拉应力主要出现在空腹顶拱处,在实际工程中应通过配筋等工程措施进行加强处理。本文的主要创新点:一、建立了包含多种典型断面的空腹重力坝通用数学优化模型,在优化过程中考虑温度荷载和坝体与基岩的接触问题,并对施工过程中采用了空腹填渣技术的坝体进行了结构分析。二、分析总结了空腹重力坝便于混凝土散热特点的实际效果,并首次提出利用空腹结构散热作为坝体的温控措施。
[Abstract]:The hollow gravity dam has the advantages of reducing the uplift pressure, reducing the quantity of concrete, facilitating the heat dissipation in the construction period and the like, and is widely adopted at home and abroad. However, there are still some deficiencies in the study of the dam type. Firstly, the optimization design of the hollow gravity dam is still in the scheme ratio selection stage, there is further optimized space; secondly, it is convenient for the heat dissipation characteristic is not paid attention all the time, the construction process simulation analysis has been in the blank. In recent years, the application of roller compacted concrete has become more and more common, and this construction technology has become an inevitable trend. Therefore, as the research object of the rolling concrete hollow gravity dam, the factors such as the temperature and the construction characteristics of RCC are comprehensively considered by means of the software platform of ANSYS. On the one hand, the optimal structure of the hollow gravity dam is put forward, on the other hand, through the simulation analysis of the thermal-stress coupling field during the construction process, the practical effect of using the hollow heat dissipation is explored. The thesis is divided into five chapters, from theory to practice. The first chapter is the introduction, the research background, the research significance, the research content, the research method and the research framework of the thesis. The second chapter is an overview of the theory of simulation analysis. The third chapter is based on the complex and diverse abdominal hole form of an empty gravity dam, establishes an optimized mathematical model which can fully express each typical section, optimizes the parameters of the abdominal hole structure by means of the ANSYS optimization module, and determines the optimal section type and the structure size; In the fourth chapter, on the basis of the optimization section, the simulation, coupling temperature and stress field of the concrete gravity dam under the same condition are compared, and the heat radiation effect of the solid gravity dam is compared with the hollow gravity dam, and the temperature field change rule of the dam body under different fasting temperature conditions during the construction period is obtained. The fifth chapter concludes that the research results are summarized. The main results are as follows: (1) The optimization module of ANSYS is applied to optimize the typical section of hollow gravity dam (urban door opening type, sector, upstream and downstream inclined walls). Aiming at the characteristics of small contact area between hollow gravity dam and dam foundation and great influence of temperature, thermal solid coupling method and contact unit are used to analyze the temperature load and anti-slip stability of dam body during the optimization process. The results show that both the upstream inclined wall and the upstream inclined wall incline to the same direction as the inner force direction of the dam body, so that the stress condition around the empty stomach is obviously improved, and because the contact area between the hollow gravity dam and the bedrock surface is small, the bottom length of the dam should not be reduced during the optimization process, The increased fasting height should be used as the main means of reducing the amount of work. After optimization, the section area is reduced by about 13. 6%, and the angle between the inclined wall and the horizontal plane at the upper and lower reaches of the optimized section is 72 ~ 76 degrees. Based on the same optimization process, five types of bedrock parameters are set to obtain the control condition and rule of the optimized section under different dam foundation conditions, and provide reference for the size ratio of the dam section under different geological conditions. On the basis of the optimization results, the cavity is replaced with filling slag to carry out further optimization, and the results show that the slag filling structure can not only provide great convenience for the construction, but also can further reduce the optimized cross-section area of the hollow gravity dam by the lifting action of the anti-sliding stability state of the dam body. (2) According to the actual engineering data, the whole process simulation calculation of the dam body with optimized cross section is carried out, the factors such as external air temperature and dam body stratification are comprehensively considered, and the change of the temperature field during the construction process is simulated by using the finite element numerical analysis method. On the basis of the calculation result, different schemes are set up to control the temperature in the empty stomach as the temperature control measure, and the simulation calculation is carried out, and the difference between the schemes and the degree of influence on the dam body are analyzed. The results show that the internal maximum temperature is 28. 88 degrees in the completion of the construction of the empty gravity dam, and the difference of the internal and external temperature difference is reduced by about 40% compared with that of the solid gravity dam. The maximum tensile stress of the solid dam during the construction period is 0. 613Mpa, the empty dam is 0.354Mpa, and the drop is 0. 259Mpa. Due to the good heat dissipation performance of the hollow dam, the generated internal temperature rise is low, and the contact area with the bedrock is small, and the temperature stress state during the construction period is more ideal than that of the solid gravity dam. However, the tensile stress of the hollow gravity dam mainly occurs at the hollow top arch, and the reinforcement treatment shall be carried out through the engineering measures such as reinforcing bars in the actual project. The main innovation points in this paper are: firstly, a general mathematical optimization model of an empty gravity dam containing multiple typical sections is established, the contact problem between the temperature load and the dam body and the bedrock is considered during the optimization process, and the structure analysis of the dam body adopting the empty filling slag technology is adopted in the construction process. Secondly, the practical effect of the hollow gravity dam to facilitate the heat dissipation of concrete is analyzed, and the temperature control measures for the dam body using the hollow structure heat dissipation are put forward for the first time.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV642.3;TV544
[Abstract]:The hollow gravity dam has the advantages of reducing the uplift pressure, reducing the quantity of concrete, facilitating the heat dissipation in the construction period and the like, and is widely adopted at home and abroad. However, there are still some deficiencies in the study of the dam type. Firstly, the optimization design of the hollow gravity dam is still in the scheme ratio selection stage, there is further optimized space; secondly, it is convenient for the heat dissipation characteristic is not paid attention all the time, the construction process simulation analysis has been in the blank. In recent years, the application of roller compacted concrete has become more and more common, and this construction technology has become an inevitable trend. Therefore, as the research object of the rolling concrete hollow gravity dam, the factors such as the temperature and the construction characteristics of RCC are comprehensively considered by means of the software platform of ANSYS. On the one hand, the optimal structure of the hollow gravity dam is put forward, on the other hand, through the simulation analysis of the thermal-stress coupling field during the construction process, the practical effect of using the hollow heat dissipation is explored. The thesis is divided into five chapters, from theory to practice. The first chapter is the introduction, the research background, the research significance, the research content, the research method and the research framework of the thesis. The second chapter is an overview of the theory of simulation analysis. The third chapter is based on the complex and diverse abdominal hole form of an empty gravity dam, establishes an optimized mathematical model which can fully express each typical section, optimizes the parameters of the abdominal hole structure by means of the ANSYS optimization module, and determines the optimal section type and the structure size; In the fourth chapter, on the basis of the optimization section, the simulation, coupling temperature and stress field of the concrete gravity dam under the same condition are compared, and the heat radiation effect of the solid gravity dam is compared with the hollow gravity dam, and the temperature field change rule of the dam body under different fasting temperature conditions during the construction period is obtained. The fifth chapter concludes that the research results are summarized. The main results are as follows: (1) The optimization module of ANSYS is applied to optimize the typical section of hollow gravity dam (urban door opening type, sector, upstream and downstream inclined walls). Aiming at the characteristics of small contact area between hollow gravity dam and dam foundation and great influence of temperature, thermal solid coupling method and contact unit are used to analyze the temperature load and anti-slip stability of dam body during the optimization process. The results show that both the upstream inclined wall and the upstream inclined wall incline to the same direction as the inner force direction of the dam body, so that the stress condition around the empty stomach is obviously improved, and because the contact area between the hollow gravity dam and the bedrock surface is small, the bottom length of the dam should not be reduced during the optimization process, The increased fasting height should be used as the main means of reducing the amount of work. After optimization, the section area is reduced by about 13. 6%, and the angle between the inclined wall and the horizontal plane at the upper and lower reaches of the optimized section is 72 ~ 76 degrees. Based on the same optimization process, five types of bedrock parameters are set to obtain the control condition and rule of the optimized section under different dam foundation conditions, and provide reference for the size ratio of the dam section under different geological conditions. On the basis of the optimization results, the cavity is replaced with filling slag to carry out further optimization, and the results show that the slag filling structure can not only provide great convenience for the construction, but also can further reduce the optimized cross-section area of the hollow gravity dam by the lifting action of the anti-sliding stability state of the dam body. (2) According to the actual engineering data, the whole process simulation calculation of the dam body with optimized cross section is carried out, the factors such as external air temperature and dam body stratification are comprehensively considered, and the change of the temperature field during the construction process is simulated by using the finite element numerical analysis method. On the basis of the calculation result, different schemes are set up to control the temperature in the empty stomach as the temperature control measure, and the simulation calculation is carried out, and the difference between the schemes and the degree of influence on the dam body are analyzed. The results show that the internal maximum temperature is 28. 88 degrees in the completion of the construction of the empty gravity dam, and the difference of the internal and external temperature difference is reduced by about 40% compared with that of the solid gravity dam. The maximum tensile stress of the solid dam during the construction period is 0. 613Mpa, the empty dam is 0.354Mpa, and the drop is 0. 259Mpa. Due to the good heat dissipation performance of the hollow dam, the generated internal temperature rise is low, and the contact area with the bedrock is small, and the temperature stress state during the construction period is more ideal than that of the solid gravity dam. However, the tensile stress of the hollow gravity dam mainly occurs at the hollow top arch, and the reinforcement treatment shall be carried out through the engineering measures such as reinforcing bars in the actual project. The main innovation points in this paper are: firstly, a general mathematical optimization model of an empty gravity dam containing multiple typical sections is established, the contact problem between the temperature load and the dam body and the bedrock is considered during the optimization process, and the structure analysis of the dam body adopting the empty filling slag technology is adopted in the construction process. Secondly, the practical effect of the hollow gravity dam to facilitate the heat dissipation of concrete is analyzed, and the temperature control measures for the dam body using the hollow structure heat dissipation are put forward for the first time.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV642.3;TV544
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相关期刊论文 前10条
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