摘要 半刚性基层沥青路面是我国高等级公路的一种主要结构形式。由于半刚性基层材料自身的缺陷和施工等方面的原因，我国既有半刚性基层沥青路面的早期损坏现象严重，其中结构性损坏主要有横向裂缝、纵向裂缝、块裂和网裂等。路面结构性能与路面物理状况有着直接的关系，例如路面开裂状况或其他的路面状况，它们削弱路面结构承受荷载的能力，导致路面需要养护。随着路面使用时间的增长和早期损坏的加重，路面养护的投入越来越大。因此，针对半刚性基层沥青路面结构破坏的特点，利用先进的FWO测试手段，建立结构性能分析和评价模式，不仅是必须的，而且具有实用价值。 本文首先在大量路况调查的基础上，提出了半刚性基层沥青路面主要的结构性损坏形式，并对之进行落锤式弯沉仪测试，根据测试结果提出路面主要结构性破损的主要特点。根据部分路面钻芯取样和室内模量测试表明，路面结构性破损出的芯样模量与完好处路面芯样模量是一致的。然后根据前人建立的路面结构层“有效模量”的衰减规律，详细分析路面各结构层自身变形的变化规律：面层结构层自身变形的大小几乎完全取决于面层有效模量的衰减程度，基本上与土基模量和基层模量无关。基层结构层自身变形主要受面层和基层模量变化的影响明显，而土基模量的变化对基层变形的影响较小。 根据FWD的冲击荷载作用过程，本文建立了半刚性基层沥青路面结构以及开裂路面的三维动力有限元模型，详细分析了各种结构破损路面的动态响应。大量计算结果表明，路表弯沉可以表征路面结构的整体强度，但无法反映各结构层的强度。进一步验证了本文提出的路面各结构层自身变形和土基顶面压应交可以合理的反映路面结构在出现裂缝等结构破损情况下的结构强度。同时计算结果合理解释了路况调查中提出的路面结构性破坏现象及其特点。路面结构状况指数PSC可以很好的表征路面裂缝处路面破损程度。本文初步建立了FWD路表弯沉盆和评价指标的回归方程，并进行了工程验证。利用本文提出的评价指标，落锤式弯沉仪FWD可以更合理的评价路面结构强度和承载力，对我国既有半刚性基层沥青路面的评价有着重要的现实意义。 关键词：半刚性基层沥青路面，有限元方法，动力响应，土基压应变，结构层自身变形，路面结构状况指数PSC ABSTRACT Semi-rigid base asphalt pavement is the main structural type of highway in China．Because of the defect of semi-rigid base’s character and the deficiency of construction, the premature failures are very serious in this pavement，in which structural damage shows as transverse crack，longitudinal crack，block crock and alligator crack．The pavement structural performance is directly effected by the structural condition of pavement．All types of crack will reduce the bearing capacity of pavement structure，which will result in the requirement of rehabilitation．With the aging and more and more serious premature failures，the cost of rehabilitation increases rapidly．Therefore，it’s necessary to put forward the method of analysis and evaluation of pavement structural performance，according to the characteristics of the existing semi-rigid asphalt pavement’s failures． Firstly，on the basis of investigation of 8 pavements，the type of structural failures，which fall in semi-rigid asphalt pavement are listed in this paper，and tested by FWI)in the pavement．By this way，the characteristics of above failures are brought out．There are also coring and testing the modulus in the laboratory．It’s found that the modulus of core in the cracking section is the same as that in the good section．It has been studied that the“effective modulus” of pavement subsystem layer is attenuated by the pavement damage．According to the principle，the own deformation of the one subsystem layer is analyzed deeply．The surface layer own deformation is just effected by the“effective modulus”of surface layer，and have little relation to the modulus of base layer and subsoil．The base layer own deformation is effected by both surface layer modulus and base layer modulus，and has little relation to subsoil． Considering the dynamic loading of FWD，the new or cracked pavement is modeled by a dynamic three-dimensional finite element method．The dynamic response of pavement under the FWD is studied，which Call reasonably interpret the damage phenomena in the semi-rigid base pavement. The result shows that the surface deflection only indicates the entire strength of the pavement，which can not indicate the strength of the subsystem layer．In the cracked pavement，the subsystem own deformation call denote the strength of itself．The strain on the surface of soil carl more reasonably indicate the pavement’s bearing capacity than the surface deformation．The pavement structural condition index PSC in the paper Can indicate the damage degree of the crack in the pavement． The regression equations between the FWD deflection basin and the indicators have been built and used in project．By this indicators，FWD may be used to reasonably evaluate the strength of asphalt pavement，which is significant to the existing semi—rigid base asphalt pavement in China． Keywords：Semi-rigid base asphalt pavement，FEM，dynamic response，compress strain of subsoil，the own deformation of the subsystem layer，pavement structure condition index PSC |
博士论文