高寒高海拔地区级配碎石路用性能研究

发布时间：2018-04-22 08:53

本文选题：高寒高海拔 + 级配碎石　；参考：《长安大学》2017年硕士论文

【摘要】：级配碎石基层是典型的柔性基层,与半刚性基层相比,可以有效防止反射裂缝。青藏高原属于高寒高海拔地区,传统的水泥稳定碎石基层开裂较为严重。本论文结合该地区气候寒冷、温差大的特点,进一步研究了级配碎石材料力学特性,对级配碎石基层在高寒高海拔地区公路路面建设中的应用具有一定的实用价值和理论意义。论文首先对G214国道、G109国道、S308省道进行了病害调研。同时开展了该地区的级配碎石原材料性质调查工作。结果表明:传统的水泥稳定碎石基层引起的路面反射开裂较为严重。此外,该地区的碎石原材料具有密度低、含泥量高、吸水率高、强度低的特点。在此基础上,根据在建花大高速公路工程实际应用情况,选取了5组具有代表性的级配,对级配碎石的CBR、回弹模量、塑性变形的展开研究。结果表明:CBR随干密度的增加而增加,饱水后CBR下降8.3%;级配碎石回弹模量随轴压、加载次数、应力比的增加而增加;塑性变形分为线性增长阶段和回弹阶段,加载次数和轴压对塑性变形有较大影响,并提出了级配碎石塑性变形的预估模型;级配碎石的围压在54kpa~94kpa与水平应变呈线性关系。骨架密实结构具有较高的CBR、回弹模量和较低的塑性变形。此外,集料形状及棱角对CBR与塑性变形影响显著,对回弹模量影响不显著。考虑到,青藏高原雨雪较多、气候寒冷以及温差较大的特点,进一步开展了透水性能与抗冻性研究。结果表明,级配碎石具有较好的透水性能,骨架密实结构具有较小的体积膨胀率,经过10次冻融破坏后,CBR最大降幅达63.6%。骨架密实结构具有较好的抗冻性。最后,结合花大高速公路级配碎石基层试验段的铺筑,完善了级配碎石施工质量控制方法。
[Abstract]:Graded crushed stone base is a typical flexible base, compared with semi-rigid base, it can effectively prevent reflective cracks. Qinghai-Xizang Plateau belongs to the high altitude area, the traditional cement stabilized crushed stone base cracking is more serious. Combined with the characteristics of cold climate and large temperature difference in this area, this paper further studies the mechanical properties of graded crushed stone materials, which has certain practical value and theoretical significance for the application of graded crushed stone base in highway pavement construction in high, cold and high altitude areas. In this paper, the disease of G214 National Highway and G109 National Highway and S308 Provincial Highway are investigated. At the same time, the investigation of the raw material properties of graded crushed stone in this area was carried out. The results show that the pavement reflection cracking caused by traditional cement stabilized macadam base is more serious. In addition, the raw materials of crushed stone in this area are characterized by low density, high mud content, high water absorption and low strength. On this basis, according to the practical application of Hua-Da Expressway, five groups of representative gradation are selected to study CBR, modulus of resilience and plastic deformation of graded crushed stone. The results show that the CBR decreases by 8.3% with the increase of dry density, the elastic modulus of graded crushed stone increases with the increase of axial compression, loading times and stress ratio, and the plastic deformation is divided into linear growth stage and springback stage. Loading times and axial compression have great influence on plastic deformation, and a prediction model of plastic deformation of graded crushed stone is proposed. The confining pressure of graded crushed stone is linearly related to horizontal strain in 54kpa~94kpa. The skeleton dense structure has high CBR, elastic modulus and low plastic deformation. In addition, the shape and angle of aggregate have significant effects on CBR and plastic deformation, but not on modulus of resilience. Considering that the Qinghai-Tibet Plateau has the characteristics of more rain and snow, colder climate and larger temperature difference, the study of water permeability and frost resistance is carried out further. The results show that graded macadam has better water permeability and smaller volume expansion ratio of skeleton compacted structure. After 10 freeze-thaw failure, the maximum decrease of CBR is 63.6%. The dense skeleton structure has good frost resistance. Finally, the construction quality control method of graded crushed stone is improved by combining with the paving of graded crushed stone base test section of Huada Expressway.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U414

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