车辆轴数与轮组对半刚性沥青路面极限轴载的影响

发布时间：2018-06-18 14:46

本文选题：半刚性沥青路面 + 极限轴载　；参考：《湖南大学》2015年硕士论文

【摘要】：目前,公路交通运输超载日益严重,沥青路面早期破坏现象越来越普遍,半刚性沥青路面在某个极限的轴载作用下一次就可以达到破坏。车辆荷载是影响路面使用寿命的关键因素之一,我国现行规范中采用单轴双轮组100k N作为标准轴载,然而调查显示,某些公路上超载车辆单轴轴重超过300k N,双轴总重在600k N以上,而无法控制过大轴载的一次作用对路面结构造成的破坏极限状态。极限轴载与路面结构、车辆轴数与轮组(即轴型)及土基模量有关,本文采用有限元方法,针对超载对路面产生的的一次破坏作用,系统和深入地研究了车辆轴数与轮组(即轴型)及土基模量对路面结构极限轴载的影响。路面结构层各层底弯拉应力随着轴载的增大而增大,达到某个值时,某结构层层底的最大弯拉应力达到该结构层材料的抗拉强度,使得该结构层发生破坏,进而整个结构发生破坏,本文定义这个值为极限轴载。研究结果表明:轴数与轮组是影响半刚性沥青路面结构极限轴载的重要因素,增加车辆的轴数或者轮组可以减轻重型车对路面的损害,保证路面结构的使用寿命;轴型系数反映了轴数与轮组对极限轴载的综合影响,极限轴载与轴型系数呈正比关系;轮组相同时,轴型系数增长的速率随轴数的增加而降低,由单轴增加到双轴、三轴及四轴时,轴型系数增长速率为50%~27%~18%;轴数相同时,轴型系数增长的速率随轮组的增加而增加,由单轮组增加到双轮组、四轮组时,轴型系数的增长速率为7.3%~13.5%。此外,车辆的轴数与轮组对土基回弹模量与路面极限轴载的关系有一定影响。不同轮轴型作用下,土基模量是影响沥青路面极限轴载的一个原因,增加土基回弹模量可以改善路面结构的受力状态,路面极限轴载随土基回弹模量的增加而近似线性地增加,对于单轴双轮组的标准轴型,土基回弹模量由20MPa增加到40MPa与60MPa时,路面极限轴载分别增加约19%和29%。
[Abstract]:At present, the overload of highway transportation is becoming more and more serious, and the early failure phenomenon of asphalt pavement is becoming more and more common. The semi-rigid asphalt pavement can be destroyed once under the action of a certain limit axle load. Vehicle load is one of the key factors affecting pavement service life. In the current code of our country, 100kN of single axle and double wheel group is adopted as standard axle load. However, the investigation shows that, The single axle weight of overloaded vehicles on some highways is more than 300kN and the total weight of two axles is more than 600kN, but the failure limit state of pavement structure caused by the primary action of excessive axle load can not be controlled. The ultimate axle load is related to the pavement structure, the axle number of vehicle and the wheel group (shaft type) and the modulus of soil foundation. In this paper, the finite element method is used to deal with the primary failure of road surface caused by overload. The effects of vehicle axle number, wheel group (shaft type) and soil modulus on the ultimate axle load of pavement structure are systematically and deeply studied. The bending tensile stress of each layer of pavement increases with the increase of axial load. When a certain value is reached, the maximum bending tensile stress at the bottom of a certain structure layer reaches the tensile strength of the material of the structure layer, which causes the failure of the structure layer. Then the whole structure is destroyed, and this value is defined as the ultimate axial load in this paper. The results show that the axle number and wheel group are the important factors that affect the ultimate axle load of semi-rigid asphalt pavement structure. Increasing the axle number of vehicle or wheel group can reduce the damage of heavy vehicle to pavement and ensure the service life of pavement structure. The axial coefficient reflects the comprehensive influence of the number of shafts and the wheel group on the ultimate axle load, and the ultimate axle load is proportional to the axial type coefficient, and when the wheel group is the same, the growth rate of the axial coefficient decreases with the increase of the number of shafts, and increases from uniaxial to biaxial. When the number of axes is the same, the increasing rate of axial coefficient increases with the increase of wheel group, from single wheel group to double wheel group, and from single wheel group to double wheel group, and from 4 wheel group to 7. 3% 13. 5% increase rate of axial coefficient. In addition, the axle number and wheel group of vehicle have some influence on the relationship between the modulus of resilience of soil foundation and the ultimate axle load of road surface. Under the action of different axle types, the modulus of soil foundation is one of the reasons that affect the ultimate axial load of asphalt pavement. Increasing the modulus of resilience of soil foundation can improve the stress state of pavement structure, and the ultimate axial load of pavement increases approximately linearly with the increase of modulus of resilience of soil foundation. For the standard axle type of single axle and double wheel group, when the elastic modulus of soil foundation increases from 20 MPA to 40 MPA and 60 MPA, the ultimate axle load of pavement increases by about 19% and 29%, respectively.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.217

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