【作者】 李骁春；

【导师】 吴胜兴；

【作者基本信息】 河海大学 ， 结构工程， 2004， 硕士

【摘要】 近年来，随着高层建筑的兴建，地下室侧墙温度裂缝这一问题越来越引起各方面的重视，如何防止高层建筑地下室侧墙开裂是工程界急需解决的难题。本文作为国家自然科学基金“现代混凝土结构裂缝机理及成套控制技术”(编号：50278031)的子题之一，对此问题进行了全面的、系统的研究，从理论计算和施工实践两方面提出了解决方案。 本文主要进行了以下几个方面的研究：(1)利用ANSYS软件，模拟了施工期地下室侧墙温度场，总结了地下室侧墙温度场分布的特点，分析了模板类型、环境变化和水泥用量等对墙体温度场的影响；(2)以大型通用有限元软件ANSYS为平台进行二次开发，运用Visual Fortran语言编写了CTS-ANSYS程序，实现了施工期混凝土徐变温度应力的仿真计算；(3)从裂缝形成的原因出发，分析了地下室侧墙厚度、长度、配筋率、配合比、膨胀剂等因素对墙体徐变温度应力的影响。 在上述研究工作的基础上取得了一些重要的研究成果：(1)地下室侧墙墙体温度变化时间较短，一般在24小时内温度达到最高，7天左右墙体内外温度趋于相同；(2)沿墙长方向的正应力是导致墙体开裂的控制应力，墙中应力较大，墙端应力较小；(3)采用钢模板支护的墙体，徐变温度应力较小，但拉应力出现较早；(4)地下室侧墙墙体越薄，徐变温度应力越小，拉应力出现时间越早；(5)地下室侧墙越长正应力越大，但当墙体长度超过一定范围后，正应力就不再增加；(6)地下室侧墙徐变温度应力的变化规律同混凝土的弹性模量及徐变特性有密切的关系，采用弹性模量变化较缓，早期徐变度较大的混凝土有助于减小拉应力；(7)添加膨胀剂的自应力混凝土在硬化过程中，可在墙体内建立预压应力，以减少拉应力；(8)框架柱和暗柱对墙体有较强的约束作用，可利用暗柱对膨胀混凝土起限制膨胀作用，使膨胀混凝土的自由膨胀转变为有效膨胀，产生自应力。 通过分析研究，在设计方案、材料要求、施工措施等方面总结了地下室侧墙温度裂缝控制的整套技术，并对无锡太湖发展大厦地下室侧墙工程进行分析研究，提出了一系列有效的施工建议。更多还原

【Abstract】 In these years, with the increase of the number of high-rise building in cities, temperature cracks of basement wall draw more and more public attentions. How to solve this problem has become a difficult nut in the engineering practice and needs urgent solutions to meet engineering demands. As a sub-topic of "cracking mechanism and a whole set of control technique of modern concrete ,structure"(NO:50278031) supported by national natural science foundation, this paper studies ail-roundly and systematically temperature crack controlling technique of basement wall of high-rise building and puts forward the solution methods into the theoretical calculation and construction practice.The main work done in this paper is as follows: (1) simulate the temperature field of basement wall by ANSYS software, sum up the characteristics of the temperature field of basement wall, and analyze the influence of the types of the molding board, environmental change and cement content; (2) the whole simulation analysis process of early-age concrete stress field is realized by sub-development of ANSYS, and CTS-ANSYS software is developed with Fortran; (3) based on the cause of cracking, the influence of the thickness of the wall, length, bar arrangement, mix proportion, expanding agent, etc, on the wall stress due to concrete creep and temperature change is analyzed.On the basis of the research work mentioned above, some crucial conclusions are acquired as follows: (1) the temperature in the basement wall changes quickly, reaching maximum temperature in 24 hours and after 7 days being the same as the temperature outside the wall; (2) the normal stress is the control stress which causes cracks in the basement wall; (3) when we use steel molding board to support wall, creeping thermal stress is small and tensile stress appears early; (4) if the basement wall is thin, the creep stress is small and tensile stress appears early; (5) the longer the basement wall is , the larger the creep stress is. But when the wall length exceeds a certain length, the normal stress would not increase; (6) the change rule of the basement wall creep thermal stress has close connection with the modulus of elasticity and creep characteristics. If the modulus of elasticity changes slowly and early stage creep slack is large, the tensile stress will be small; (7) in hardening process, the self-stressing concrete added expanding agent can produce compressive pre-stress in the wall to reduce tensile stress; (8) frame columns and embedded columns have strong restriction, and we can use those columns to restrict free expansion, and to change free expansion into efficient expansion.By analysis and study, the methods of controlling the thermal crack in basement wall have been summed up in design, material supply and construction. These methods have been applied in Wuxi Development Building basement wall project, and a series of efficient measures methods have been proposed.更多还原