基于光纤光栅传感技术的沥青路面行车工况下力学响应研究

Mechanical response of asphalt pavement under driving conditions by fiber bragg grating optical sensing technology

为揭示半刚性基层沥青路面内部真实力学响应规律,为耐久性路面设计提供参考。通过现场埋设光纤光栅传感器,基于真实荷载工况开展了不同车速与轴载作用下沥青路面应变测试试验。测试结果表明:沥青面层轮载中心拉应变最大,为该层最不利荷载点位;静载应变历时曲线黏弹性明显,且很好地符合Bugers模型,拟合判定系数为0.98;动载应变曲线呈现明显的压-拉-压波形。水稳碎石基层轮隙中心拉应变最大,为该层最不利荷载点位;静载应变历时曲线符合弹性性质,动载应变曲线主要表现为拉峰波形。构建了路面结构层层底应变随轴载和车速变化的理论函数模型,并得到了纵向动应变压峰与拉峰的峰值比值随车速变化的规律。其研究成果可供耐久性沥青路面设计及室内疲劳试验参考。

To reveal real mechanical response law in semi-rigid base asphalt pavement and provide references for the design of durable pavement, the strains of asphalt pavement under realistic cases of vehicle speeds and axle loads were tested by fiber bragg grating optical sensors. Test results show that the most unfavorable load position on asphalt surface layer is the center of wheel load where the largest tensile strain in this layer can be observed ; viscoelasticity is manifested obviously in the duration curve of static strain, conforming with obvious compression-tension-compression waveform is shown in the Bugers model by a fitting coefficient of 0.98; An the dynamic strain curve. The most unfavorable load position of cement stabilized macadam base layer is the gap center of two wheels where the largest tensile strain in this layer can be observed; The elastic behavior is manifested in the duration curve of static strain and the tension waveform with a peak is mainly presented in the dynamic strain curve. Theoretical function models were established for the strain at the bottom of pavement layers changing with axle load and vehicle speed, and the law for the ratio of compressive peak to tensile peak of the longitudinal dynamic strain changing with vehicle speed was obtained. The research results can be referred in the design of durable asphalt pavement and fatigue tests in laboratory.