车辆速度对沥青路面动力响应影响试验研究

Experiment Study on the Influence of the Vehicle Velocity on the Asphalt Pavement Dynamic Response

通过野外现场试验,检测运动车辆荷载下沥青路面各层层底的动应变响应,以面层底部的动应变为分析对象,研究车辆速度对沥青路面结构动力响应的影响.研究结果发现,面层底部动应变既包括拉应变,又包括压应变,呈拉压应变交变状态,一定应力比下沥青混凝土的疲劳寿命与简单拉应力下的疲劳寿命差异严重,进行沥青路面结构设计时,应以应变或应力循环范围为动态设计控制参数;随着车速提高,最大拉应变和应变幅度总体呈现下降趋势,最大压应变和应变比总体呈上升趋势.重载车辆在低速状态对路面的破坏作用更加严重.应变比既受轴重的影响又受速度的影响,正常车辆速度下,14 t后桥轴重车辆作用下面层底部应变比约-2.6^-2.1,20 t后桥轴重车辆作用下面层底部应变比约-4.4^-3.6.

To study the dynamic response of the asphalt pavement under real traffic load, the dynamic strain at the bottom of each layer was examined in field, and the influence of the vehicle speed on the dynamic response of the asphalt pavement was discussed based on the the dynamic strain at the bottom of the AC layer. The resuits show that there is not only tensile strain but also compressive strain in the dynamic response, especially, there is quite difference between the fatigue life of asphalt concrete under some strain ratio condition and that under simple tension condition, so the strain or stress changing scope should be considered as a design parameter. With the increase of running speed, the maximum tensile strain and strain changing scope decrease, while the maximum compressive strain and strain ratio increase as a whole. Therefore, the fatigue damage caused by slow speed truck is more serious than that by high speed truck. The strain ratio is markedly affected by axle load, such as the strain ratio is about -2.6 ～ -2.1 when vehicle axle load is 14t, while it is about - 4.4 ～ - 3.6 when vehicle axle load is 20 t.