## 3 Results and Discussion
### Sensitivity of Various Influencing Factors on Asphalt Pavement  
The entropy method was used to analyze the influence data of various working conditions on the mechanical response of the pavement crack tip in the foregoing three sections to obtain the primary and secondary relationship of the influence of various factors on the different mechanical responses. In the entropy analysis of this paper, the schemes to be evaluated are load effect, surface layer modulus, middle surface layer modulus, and bottom surface layer modulus. Each scheme has 10 working conditions. This paper counted the values of S33, S23, J-integral, K1, K2 under each working condition, taking the working condition as the vertical column and the evaluation plan as the horizontal row, and calculating the influence of each factor on them under 10 working conditions, and determined the weight of these influencing factors at the same time. The weight of the influence of various factors on S33, S23, K1, and K2 is shown in Table 2.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Mechanical Response** & **Surface Layout Modulus** & **Middle Surface Layer Modulus** & **Bottom Surface Layer Modulus** & **Traffic Load** \\ \hline J & 0.2444 & 0.2365 & 0.2558 & 0.2633 \\ K1 & 0.2443 & 0.2402 & 0.2872 & 0.2283 \\ K2 & 0.1846 & 0.1817 & 0.4262 & 0.2076 \\ S23 & 0.2335 & 0.2297 & 0.2791 & 0.2577 \\ S33 & 0.2528 & 0.2533 & 0.2568 & 0.2370 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Weight of various factors.  
Figure 10: (**a**) J-integral curve with modulus (**b**) K1 curve with modulus (**c**) K2 curve with modulus.  
It can be seen from the table above that among the factors that affect the J-integral, the modulus of the bottom surface layer of the surface layer is the most important factor, and the modulus of the surface layer and the middle surface layer modulus have the least influence. The factor that has the greatest influence on the four mechanical responses is the modulus of the bottom surface layer. This is because the bottom surface layer is the closest to the crack area. When the crack propagates to the bottom surface layer, the stress intensity and energy required for further expansion need to be accumulated at the contact between the bottom surface layer and the base layer. When the modulus of the bottom surface layer increases significantly, the cracking tendency becomes smaller, the cracks need to accumulate on the contact surface for a longer time, and the load needs to continue to act. Therefore, the most direct factor affecting the crack propagation process is the bottom surface layer modulus. However, the effects of several other factors need to be transmitted to the fracture area through the bottom surface layer, and the effect on the fracture area is not very direct. In addition, the analysis results also show that loads are not the most important factor affecting the mechanical response of the crack area, but from the foregoing analysis, it can be seen that they have a significant impact on the numerical value of the mechanical response of the crack area, far exceeding other working conditions. Therefore, special attention should be paid to controlling the traffic load.