Stress Analysis Of Heavy-load Road Structural Layer And Evaluation Of The Bonding Condition Between Interlayer

Overload can increase the cumulative equivalent axle loads dramatically and it can also cause fatigue cracking, rutting, shear move and other forms of early destruction, thus the service life of the road will be reduced and the highway construction investment benefit will be influenced greatly. The mechanical response analysis of the road strctural layer under different working conditions is helpful to road design and management. According to the national asphalt pavement design standard, the contact of layers is assumed to be completely continuous, which is inconsistent with the actual situation. In this assumption for theoretical calculation, the accuracy of the results is hard to ensure. So it is very important to evaluate the bonding condition and eliminate the bad combination between layers, both during and after construction, for it has a very vital significance to the prediction of early distress, road maintenance and repair plan.Based on a Logistics channel in Henan province, the road model and materials in this paper are chosen in accordance with the actual engineering. By analyzing the mechanical response of road under different conditions with Abaqus software, the deflection basin indexs are used to evaluate road combination condition of interlayer, and the evaluation results are verified by contrasting the field test. The main contents and conclusions of the paper are as follows:1. The conditions of heavy load and overload of the existing high level roads are investigated and the range of load and the model of wheel seal are confirmed.2. Abaqus are used to analyze the mechanics responses under different conditions (overload, horizontal stress, different friction coefficients between interlayer). The results suggest:Both the maximum deflection and the maximum compressive stress have good linear relationships with load level, with or without the horizontal stress. The sharing stress at the bottom of surface have a great increase when the horizontal stress was added. Friction coefficient between interlayer has a great influence on max deflection value, tensile stress under upper layer and the difference between radial stresses directly above and below the interlayer. Friction coefficient between surface and base has a great influence on surface deflection, while friction coefficient between upper surface and under surface has a great influence on tensile stress under upper layer.3. The relations between friction coefficients and deflection basin indexes are established, and the bonding conditions between interlayers are evaluated in deflection basin indexes. The results suggest:Friction coefficient between upper surface and under surface has a good relationship with F1/F2. Friction coefficient between surface and base has a good relationship with AI1/AI2、F1/F2and SCI/BCI.4. Shearing tests are carried on the drill sample of the the corresponding point in the test section to verify the evaluation results. The results suggests:Evaluation results and the measured results are consistent, and the deflection basin index F1/F2can be used to evaluate the bonding conditions between upper and under surfaces.