【作者】 乐建新；

【导师】 高培伟；

【作者基本信息】 南京航空航天大学 ， 结构工程， 2008， 硕士

【摘要】 机场水泥混凝土道面从早期施工阶段到服役期使用阶段,全过程均可能有裂缝产生。一旦开裂破坏,道面的维修将耗费大量的人力和物力。研究水泥混凝土道面的开裂破坏机理,确定水泥混凝土道面全过程开裂风险的影响因素意义重大。本文通用有限元分析软件对水泥混凝土道面的全过程开裂趋势进行建模分析。在早期施工阶段,为计算温度场,同时考虑了温度和龄期对水泥水化反应速率的影响,并运用水化度理论弥补了传统水泥水化热公式的不足;为计算温度应力,运用成熟度理论,考虑了温度和龄期对水泥混凝土强度和弹性模量发展的影响;为计算早期综合应力场,运用了松弛系数法和当量温差法,并考虑了徐变和收缩的影响。在服役期,通过计算多轮静载及冲击荷载作用下水泥混凝土道面的力学响应,揭示了各道面结构参数等多种因素引起道面开裂的敏感性。本文建立了以温度场和应力场理论为基础的道面结构模型、以弹性层状半空间地基为基础的道面结构模型。利用有限元计算模型,对水泥稳定碎石基层上水泥混凝土道面开裂趋势的影响因素进行了数值模拟。在早期施工阶段本文分别考虑了水泥水化热、水泥用量、浇筑温度、环境温度、面层厚度、最终收缩值、徐变、弹性模量和热膨胀系数等影响因素;在服役期使用阶段本文分别考虑了面层厚度、面层弹模、基层回弹模量、土基回弹模量以及基层脱空等影响因素。通过分析最大主拉应力,讨论了各因素对开裂的影响程度。本文的研究内容和结论为今后机场水泥混凝土道面的设计提供了参考。最后,指出了本文研究的不足,并提出了今后进一步研究方向。更多还原

【Abstract】 Cracks appear in concrete pavement in stages from construction to service, and the repairing work is time and money consuming. Accordingly, there is an urgent demand to determinate the cracking mechanisms and the factors that influence the cracking tendency of the concrete pavement.In this paper, the cracking of concrete pavement in stages from construction to service was modeled using the universal finite element analysis software. In construction stage, in the temperature field calculation, both the effects of temperature and age on the rate of cement hydration were in consideration, and the theory of hydration degree was used to offset the defect of conventional cement hydration heat formula. And in the calculation of thermal stress field, both the effects of temperature and age on the strength and modulus of elasticity development of concrete were in consideration and the theory of mature degree was used. Moreover, the methods of relaxation coefficient and equivalent difference in temperature were used in consideration of the effects of creep and shrinkage in integrative stress field calculation. In service stage, the mechanical responds of concrete pavement under static loads and impact loads of aircraft are analysed. Based on these responds, the influence of material parameters to stress and cracking tendency are revealed.This paper simulates the cracking of concrete pavement on the cement stabilized macadam foundation through numerical modeling. Based on the theory of temperature and stress field and elastic half-space foundation, two three-dimensional finite element analysis models of concrete pavement were established. In construction stage, The influence of each factor was discussed by analyzing the greatest principal tensile stress and cracking risk, such as cement hydration heat, content of cement, thickness of concrete slab, casting temperature, ambient temperature, ultimate shrinkage, creep, modulus of elasticity and coefficient of thermal expansion. In service stage, the influence of some main factor was discussed by analyzing the greatest principal tensile stress and cracking risk, such as concrete slab depth, concrete slab modulu, base modulu, foundation rebound modulu and so on. Problem of cavity beneath the cement-concrete slab and its effects was analysed. The content and conclusions of above may provide a reference for design and research of concrete pavement.Finally, the existing shortages of the research were indicated and the research direction in the future was put forward.更多还原