热膨胀系数对刚性路面面板设计的影响分析

发布时间：2018-08-03 11:58

【摘要】：水泥混凝土路面具有刚度大、扩散荷载能力强；强度高、疲劳寿命长；平整度衰减慢、能维持较长时间的高平整度等优点，是高等级路面结构的主要形式之一，近些年来被广泛应用，特别是低等级公路、工矿道路和机场跑道，水泥混凝土路面的应用更加普遍，截止到2012年底，我国水泥混凝土路面公路里程约占公路总里程的39%。但水泥混凝土路面面层板边缘的过早破坏、面层开裂、横缝错台等病害一直困扰着道路工程界。研究中发现：水泥混凝土的热膨胀系数对于水泥混凝土路面结构设计有一定的影响。但是目前大多数研究主要是分析热膨胀系数值的影响因素，对热膨胀系数如何影响水泥混凝土路面结构设计的研究很少。笔者主要针对热膨胀系数对水泥混凝土路面结构设计的影响进行了分析探讨。 为了研究热膨胀系数对水泥混凝土路面结构设计的影响，根据我国水泥混凝土路面设计标准方法和美国力学经验设计法，分别采用相应的路面设计软件计算了热膨胀系数对水泥混凝土面层板厚度设计的影响，，分析其原因，由于设计标准不同，热膨胀系数对路面厚度设计的影响存在显著差异。我国水泥混凝土路面设计中，热膨胀系数只直接影响温度应力，而美国力学经验设计法，更多地考虑了热膨胀系数对接缝传荷能力以及板角翘曲变形的影响。据此，根据我国规范以及有限元软件数值模拟分析了热膨胀系数对面层板温度应力的影响，同时采用美国力学经验设计法分析了热膨胀系数对水泥混凝土路面横向开裂率以及横缝错台量的影响。并提出了接缝传荷能力预测模型以及水泥混凝土路面疲劳应力计算新思路。 结果表明：（1）热膨胀系数对水泥混凝土面层板温度疲劳应力的影响很大，热膨胀系数每增加1×10-6/℃时，温度疲劳应力都会增加10%以上，甚至达到59%。（2）热膨胀系数对水泥混凝土面层板横缝错台量以及横向开裂率的影响都非常大，热膨胀系数每增加1×10-6/℃，横缝错台量增加65%，横向开裂率可以增加400%。（3）热膨胀系数对接缝传荷能力以及板角翘曲变形的影响会直接改变水泥混凝土路面设计厚度。 因此，在我国水泥混凝土路面设计中要充分考虑热膨胀系数对温度疲劳应力、接缝传荷能力以及板角温度翘曲变形的影响，优化接缝传荷能力预测模型，改进温度疲劳应力计算方法，并建立适合我国状况的公路水泥混凝土热膨胀系数值试验规程，这可以有效减少水泥混凝土路面病害，为水泥混凝土路面的进一步优化提供参考。
[Abstract]:Cement concrete pavement has the advantages of high stiffness, strong diffusive load capacity, high strength, long fatigue life, low flatness attenuation, and can maintain high smoothness for a long time, so it is one of the main forms of high grade pavement structure. In recent years, it has been widely used, especially in low-grade highway, industrial road, airport runway and cement concrete pavement. Up to the end of 2012, the mileage of cement concrete pavement in China accounts for 39% of the total road mileage. However, the premature destruction of the edge of the cement concrete pavement surface slab, the cracking of the surface layer, the cross joint staggered platform and other diseases have been puzzling the road engineering field. It is found that the coefficient of thermal expansion of cement concrete has a certain influence on the structural design of cement concrete pavement. But at present, most of the research is mainly to analyze the influence factors of the coefficient of thermal expansion, and there is little research on how the coefficient of thermal expansion affects the design of cement concrete pavement structure. The influence of thermal expansion coefficient on the design of cement concrete pavement structure is analyzed and discussed in this paper. In order to study the influence of thermal expansion coefficient on the structural design of cement concrete pavement, according to the standard design method of cement concrete pavement in China and the design method of American mechanics experience, The influence of thermal expansion coefficient on the thickness design of cement concrete surface slab is calculated by using the corresponding pavement design software, and the reasons are analyzed. Because of different design standards, the influence of thermal expansion coefficient on pavement thickness design is obviously different. In the design of cement concrete pavement in China, the thermal expansion coefficient only directly affects the temperature stress, while the influence of the coefficient of thermal expansion coefficient on the load transfer capacity of the butt joint and the warping deformation of the plate angle is more considered in the empirical design method of American mechanics. According to the code of our country and the numerical simulation of finite element software, the influence of thermal expansion coefficient on the thermal stress of the opposite laminate is analyzed. At the same time, the influence of thermal expansion coefficient on the transverse cracking rate of cement concrete pavement and the number of transverse joints are analyzed by means of the empirical design method of American mechanics. A prediction model of joint load transfer capacity and a new method for calculating fatigue stress of cement concrete pavement are put forward. The results show that: (1) the thermal expansion coefficient has a great effect on the thermal fatigue stress of cement concrete surface slab. When the thermal expansion coefficient increases by 1 脳 10 ~ (-6) / 鈩

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