荷载横向扩散式组砌道面结构性能分析

发布时间：2018-05-29 17:50

本文选题：机场道面 + 荷载横向扩散　；参考：《中国民航大学》2017年硕士论文

【摘要】：组合铺砌式道面以其可快速便捷的建设与修复等优势在城市建设中得到较广泛应用,但是,普通垂直接缝的组砌道面因缺少横向约束而难以承受较高的荷载,使其在较重车辆荷载作用下容易产生严重沉陷或错台等失稳现象。然而,随着城市、港口与机场道面等使用荷载的不断提高,组砌道面结构的荷载横向扩散能力越来越重要,需要通过提高组砌道面结构的荷载扩散能力来适应不断提高的交通要求。本文以组砌道面结构荷载扩散效应为研究目标,分析了改进型组砌道面结构荷载横向扩散的基本原理,探讨了该结构的力学分析表达模型;基于对重载下组砌道面结构的荷载横向扩散性能理论分析、有限元数值模拟,研究了该组砌道面结构的受力特性及其变形规律;基于组砌道面结构的室内试验研究结果,探讨了重载作用下组砌道面结构受力特性,提出了该结构在飞机荷载作用下的适宜结构参数选择原则与要求。有限元数值模拟结果表明,砌块长边尺寸和厚度对路表弯沉的影响与土基强度有关,土基强度较高时,对于砌块长边尺寸较大以及厚度较厚的组砌道面来说,弯沉降低效果更佳,但考虑施工便捷性,砌块厚度不宜超过200mm;土基回弹模量从20MPa~80MPa变化时,可以有效降低路表弯沉和基层顶面压应变,但当土基回弹模量超过50MPa时,继续增加土基回弹模量的大小对减小组砌道面结构的道面弯沉和基层顶面压应变效果有所降低;基层厚度在160mm~220mm之间变化时,路表弯沉和基层顶面压应变显著减小;组砌道面结构在荷载作用下,块体组合边缘和角部最容易出现应力集中现象,特别是当斜侧面倾角超过45°时,这种应力集中现象更严重。有限元数值模拟和室内试验研究的结果还表明,随着组砌道面砌块长边尺寸、块体厚度、砌块侧面倾角的增大,道面路表弯沉和基顶压应变均相应减小,其中砌块倾角对于路面受力影响最大,当砌块倾角从15°增大到30°时,基层顶面压应变减小最大可达21%,道面弯沉降低幅度最大可达40%左右,并且在砌块长边尺寸较大和土基模量较小时,这种降低效果更加显著,但考虑块体边角效应倾角不宜大于45°。
[Abstract]:Composite paving pavement has been widely used in urban construction because of its advantages of quick and convenient construction and restoration. However, the common vertical joint road surface is difficult to bear higher load due to the lack of transverse constraints. It is easy to cause serious subsidence or stagger instability under heavy vehicle loads. However, with the increasing use of loads in cities, ports and airports, the lateral diffusion capacity of masonry pavement structures is becoming more and more important. It is necessary to adapt to the increasing traffic requirement by improving the load diffusion capacity of the masonry pavement structure. In this paper, the basic principle of transverse load diffusion of the improved masonry pavement structure is analyzed, and the mechanical analysis model of the structure is discussed. Based on the theoretical analysis and finite element numerical simulation of the load transverse diffusion performance of the masonry pavement structure under heavy load, the stress characteristics and deformation law of the structure are studied. In this paper, the mechanical characteristics of the pavement structure under heavy load are discussed, and the selection principles and requirements of the appropriate structural parameters for the structure under aircraft load are put forward. The results of finite element numerical simulation show that the influence of the length and thickness of block on the deflection of road surface is related to the strength of soil foundation. The effect of deflection reduction is better, but considering the convenience of construction, the thickness of block should not exceed 200mm. When the elastic modulus of soil foundation changes from 20MPa~80MPa, the deflection of road surface and the compressive strain of base top can be effectively reduced, but when the modulus of resilience of soil foundation exceeds 50MPa, Increasing the elastic modulus of soil foundation decreases the deflection of pavement surface and the compressive strain effect of base top surface, and when the thickness of base course changes between 160mm~220mm, the deflection of road surface and the compressive strain of base top surface decrease significantly. The stress concentration in the composite edge and corner of the block is most likely to occur under the load, especially when the inclined angle of the inclined side is more than 45 掳, the stress concentration is more serious. The results of finite element numerical simulation and laboratory test also show that with the increase of the size of the long side of the block, the thickness of the block and the inclined angle of the block, the deflection of the pavement surface and the pressure strain of the base top decrease accordingly. When the slope angle of the block increases from 15 掳to 30 掳, the compressive strain of the top surface of the base can be reduced to 21, and the deflection of the pavement can be reduced by about 40%. The effect of this reduction is more obvious when the size of the long side of the block is larger and the modulus of the soil foundation is small, but the obliquity angle of the block side effect should not be greater than 45 掳.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.2

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