【作者】 肖水华；

【导师】 吴方伯；

【作者基本信息】 湖南大学 ， 结构工程， 2004， 硕士

【摘要】 本文旨在研究地下室外墙板裂缝控制，其模型实质是对受基础约束墙板裂缝控制的研究。首先研究了基础对墙板的约束程度，通过大量数值计算，回归拟合得到了不同长高比、不同长度的钢筋混凝土墙板在发生非荷载变形时受基础的约束程度。回归公式表明，墙板上不同点所受基础的约束程度不仅与墙板的长高比有关，而且还与墙板的长度、高度两个单项因素有关。本文的计算结果与ANSYS计算结果对比表明，拟合公式能较好地反映墙板上各点受基础约束程度，使约束程度的计算公式具有连续性和通用性。有了这一拟合公式后，计算墙板控制截面、控制点上的各非荷载变形引起的非荷载应力将变得较为简单。 利用非荷载应力简化计算方法，对各种非荷载应力进行了计算分析。分析研究表明气候变化引起的温度应力、混凝土的收缩应力和水化温升引起的温度应力是引起墙板开裂的主要因素。最后编制了综合非荷载应力计算程序和裂缝控制设计流程，供裂缝控制设计和抗裂分析使用。 对构造配筋、设置应力释放带和使用微膨胀混凝土等控制裂缝的有效措施进行了讨论。分析墙板受基础约束程度的变化规律，可知构造配筋的作用效果可以直接按照仅两端受固支约束的构件进行讨论，讨论结果表明通过构造配筋可以提高外墙墙板的抗开裂能力和有效控制墙板开裂之后的裂缝宽度发展，并提出了混凝土应力应变与配筋率之间的关系、合理的配筋率、裂缝宽度与配筋率之间的关系、裂缝宽度与裂缝数量之间的定量关系等，可以作为设计控制的理论依据。 对设置应力释放带的地下室外墙板进行了非荷载应力对比计算。通过分析可知，设置释放带宜短些，否则失去作用。在此基础上推导了微膨胀混凝土的极限伸缩缝长度计算实用公式。 本文取湖南省的最不利气候条件，讨论了在使用微膨胀混凝土时如何通过温度控制进行裂缝控制。定量计算的结果可以用于指导实际工程设计。更多还原

【Abstract】 This paper aims to control the cracking and the crack development of reinforcement concrete basement outer-wall. Firstly the base constraint coefficient of the concrete wall was studied when non-load deformation occurred. A simple formula was achieved by computing lots of reinforcement concrete walls with different length/height ratio and different length, and then regressing these resulting data. With this formula, to compute the volume change and the corresponding stress is rather simplified because the calculation results accord well with the FEM program.After the non-load deformation of concrete wall and the corresponding stresses fully studied, the main factors inducing to crack are found out. The non-load deformation of wall constrained by base mainly includes the thermal deformation and the shrinkage deformation of concrete. Studies show that the cracking stress mainly induced by the seasonal change of temperature, the shrinkage of concrete and the residual stress caused by hydrate temperature.The volume change of concrete wall and the corresponding stresses are closely related to the nonlinear properties of concrete. A program considering the nonlinear properties of concrete was developed. With the program the design of crack control conform to procedures planned in flow chart.Reinforcing concrete wall, grooving a stress-release slot in basement wall and adopting tiny expansive concrete are good measures to control the cracking. Analyzing the base constraint coefficient along the length shows that the efficient of reinforcement can be discussed by analyzing the fully constrained reinforced members. So based on this conclusion this paper followed discussed the relationship of concrete strain and stress to the steel ratio, the relationship of crack width to steel ratio, quantitative relationship of crack width to crack number and the rational steel ratio, all of which can be regarded as theoretic basement for design.This article emphasize particularly on the stress development by contrasting before grooving a stress-release slot in the basement wall with after doing so. The results prove setting stress-release slot is a effective design if the length of reinforcement concrete basement slab-wall is limited in reason. The simplifying formulas and design suggestion are proposed.Basing the most disadvantageous weather data of the Hunan province, thelast part of paper discusses how to control cracking by controlling the temperature of tiny extended concrete. Calculation results can be used to guide the practical engineering design.更多还原