基于三维探地雷达和落锤式弯沉仪的旧水泥混凝土路面疲劳性能评估

Evaluation of Fatigue Performance of Old Cement Concrete Pavement Based on Three-Dimensional Ground Penetrating Radar and Falling Weight Deflectometer

摘要:

为提高旧水泥混凝土路面的结构健康状况和疲劳性能的评估准确性。首先，考虑到旧水泥面板的厚度、模量等关键技术参数与疲劳性能评估结果的显著相关性，采用三维探地雷达（3D-GPR）和落锤式弯沉仪（FWD）准确获得了旧水泥混凝土路面的水泥混凝土层厚度h_c、水泥混凝土层模量E_c、基层模量E_t等参数，进而从提高结构参数准确性角度增强了评估方法的可靠度。然后，评估了各结构层强度状况与损坏状况之间的相关关系，建立了旧水泥混凝土路面疲劳性能评估模型。最后，分析了h_c、E_c、E_t的变化对路面疲劳性能及水泥混凝土层内部疲劳应力的影响。结果表明：在旧水泥面板因接缝传荷系数下降而导致应力集中和开裂后，面层和基层强度息息相关，两者相互影响。当h_c和E_c、E_t均降幅度1 %时，h_c引起的疲劳寿命N_e的下降幅度接近E_c、E_t引起的3倍。 h_c为影响路面疲劳性能的最关键参数，E_t及E_c的降低只会小幅改变路面内部的荷载和温度疲劳应力水平。

Abstract:

To improve the accuracy of fatigue performance evaluation for old cement concrete pavement， a comprehensive approach was adopted. First， considering the significant correlation between the key technical parameters such as the thickness and modulus of the old cement panel， and the fatigue performance， three-dimensional ground-penetrating radar （3D-GPR） and a falling weight deflectometer （FWD） were used. These tools enabled the precise acquisition of structural parameters such as the thickness of cement concrete layer （h_c）， the modulus of cement concrete layer （E_c ）， and the modulus of base layer（E_t ）， which enhanced the reliability of the evaluation method by improving the accuracy of structural parameters. Then， the relationship between the strength condition and damage status of each structural layer was evaluated， and a fatigue performance evaluation model for old cement concrete pavement was established. Finally， the effects of variations in h_c， E_c， and E_t on the fatigue performance of pavements and the internal fatigue stress of the cement concrete layers were analyzed. The results indicate that the strength of the surface layer and the base layer are closely related when the stress concentration of the old cement panel is caused by a decrease in the joint load transfer coefficient， and the two affect each other. When both h_c and E_c， E_t decrease by 1 %， the decrease in fatigue life （N_e） caused by h_c is close to three times that caused by E_c and E_t. h_c is the most critical parameter affecting the fatigue performance of the cement pavement， and the reduction of E_t and E_c only slightly changes both load-induced and temperature-induced fatigue stress inside the cement pavement.