新疆干旱地区粗粒土路基强度衰减对路面耐久性的影响研究

发布时间：2018-08-02 08:29

【摘要】：路基是路面结构层的重要组成,承受道路表面传递下来的车辆荷载,是路面结构层的基础。路基强度对路面耐久性和道路稳定性有直接影响。根据对国内现有道路的调查发现,由路基导致的路面前期破坏占到60%。另外,在路面的破坏中,一般还会与强度不高,压实度不足,路基积水,超载等有关,并且,在后期的修复会产生很高的费用,对道路耐久性产生重要影响。本文重点对新疆干旱地区粗粒土的分布与颗粒组成及受力后力学特性变化特征等系统的进行了研究。选取新疆干旱地区典型路段作为试验路,系统分析了土质、含水量及压实度等因素对路基强度的影响程度,得到相应的函数关系。另外,为了能够方便快捷的检测路基强度,通过回归分析建立了回弹弯沉和回弹模量的函数关系,并利用统计学推荐了回弹模量值。路基承受道路表面传递下的行车荷载,路面结构内部产生应力、应变等。如果路基没有足够的强度,在车辆荷载的反复作用下,路面结构将会产生变形,路面将产生车辙、开裂,不均匀沉降等病害,疲劳寿命降低,使用年限降低。利用bisar3.0程序,根据新疆干旱地区粗粒土的回弹模量测试结果和实际的轴载情况,针对新疆干旱地区粗粒士路基强度衰减后和超载情况共同作用下对路面结构受力特征的影响程度进行了系统研究,分析基层层底拉应力、基层表面压应变、路表弯沉的变化规律,明确路面结构层在路基强度衰减和超载条件下的受力性能。同时,利用破坏接近度理论评价了新建和衰减后的路面结构的平衡性,为设计受力平衡的路面结构形式提供一种方法。
[Abstract]:Subgrade is an important component of pavement structure layer. It is the foundation of pavement structure layer to bear the vehicle load transferred from the road surface. Subgrade strength has direct influence on pavement durability and road stability. According to the investigation of the existing roads in China, the early damage caused by the roadbed accounts for 60%. In addition, in the damage of road surface, it is generally related to low strength, insufficient compaction, stagnant subgrade, overload and so on. Moreover, the repair in the later period will have a high cost, which will have an important impact on the durability of the road. In this paper, the distribution and particle composition of coarse grained soil in arid area of Xinjiang and the variation characteristics of mechanical properties after loading are studied. In this paper, the influence of soil quality, water content and compaction on the strength of roadbed is systematically analyzed, and the corresponding functional relationship is obtained. In addition, in order to detect the strength of roadbed conveniently and quickly, the functional relationship between springback deflection and modulus of springback is established by regression analysis, and the value of rebound modulus is recommended by statistics. The roadbed bears the traffic load transmitted by the road surface, and the stress and strain are generated in the pavement structure. If the subgrade does not have enough strength, under the repeated action of the vehicle load, the pavement structure will produce deformation, the pavement will produce rutting, cracking, uneven settlement and other diseases, the fatigue life will be reduced, and the service life will be reduced. According to the results of the elastic modulus test and the actual axial load of coarse grained soil in arid area of Xinjiang, the bisar3.0 program is used. In view of the influence of intensity attenuation of coarse grained subgrade and overload on the stress characteristics of pavement structure in arid area of Xinjiang, the influence degree of the stress on pavement structure is systematically studied, and the tensile stress and compressive strain on the surface of base course are analyzed. The variation law of pavement surface deflection and the mechanical performance of pavement structure layer under the condition of roadbed strength attenuation and overload. At the same time, the equilibrium of the new and attenuated pavement structure is evaluated by using the theory of damage proximity, which provides a method for designing the pavement structure with balanced force.
【学位授予单位】：新疆农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416

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