足尺沥青混凝土路面加速加载动力响应

Accelerated loading dynamic response of full-scale asphalt concrete pavement

采用足尺沥青混凝土路面加速加载试验设备,检测了移动车辆荷载下路面结构的动力响应,分析了面层底部的动应变和土基顶竖向压应力,研究了车辆轴重、行驶速度和轮胎胎压对路面结构动力响应的影响,分别建立了动力响应与轴重、车速的回归模型,在不同轴重、车速和胎压下对4种路面结构进行了试验。分析结果表明:在行车荷载作用下,面层底部应变响应呈拉压应变交变状态;在中等试验温度条件下,面层底部应变响应随轴重的增加而线性增加,土基顶竖向压应力呈单向应力状态,且随轴重增加而增大;车速显著影响面层底部应变响应,但对竖向压应力影响不大,仅影响应力的脉冲持续时间;随车速增加,应力脉冲时间缩短,面层底部应变响应减小;重载车辆在低速行车时对路面的破坏作用更严重,但胎压对面层底部应变和土基顶竖向压应力影响较小。

The dynamic response of pavement structure under moving vehicle loads was measured by using the accelerated loading test facility of full-scale asphalt concrete pavement.The dynamic strain at the bottom of surface layer for the pavement and the vertical compressive stress at the top of subgrade were taken as analysis objects,and the influences of axle load,speed and tire pressure on the dynamic response were studied.The regression models among dynamic response,axle load and speed were established respectively.Four kinds of pavement structures were tested in different axle loads,speeds and tire pressures.Analysis result shows that under moving vehicle loads,the strain response at the bottom of surface layer is in the alternative condition of tensile strain and compressive strain.Under intermediate test temperature,the strain response at the bottom of surface layer increases linearly with the increase of axle load,the vertical compressive stress at the top of subgrade shows uniaxial stressed state,and it increases with the increase of axle load.Speed affects the strain response at the bottom of surface layer significantly,but it has little influence on the vertical compressive stress,and affects the stress pulse duration only,and the stress pulse duration and strain response at the bottom of surface layer reduce with the increase of speed.The destroy degree of pavement is more serious in low speed and heavy load,but tire pressure has little influences on the strain at the bottom of surface layer and the vertical compressive stress at the top of subgrade.5 tabs,13 figs,14 refs.