## 3 Results
### Analysis of the Depth of Influence
#### 3.5.2 Analysis Process  
Figure 14 depicts the variation in equivalent amplitude between scheme 1 and scheme 2. The equivalent amplitudes at the top of the roadbed are more similar between the two schemes than the main frequency amplitudes. At the same driving speed, the excitement experienced by both sides is the same. The upper structure of gravelly soil is identical to that of geocell-reinforced aeolian sand. Thus, the equivalent amplitude is more comprehensive than the maximum amplitude and is a more comprehensive measure of vibration velocity.  
The vertical attenuation of scheme 1 has an obvious turning point at 0.96 m. It indicates that the surface material of gravelly soil has similar effects on vibration from the perspective of energy attenuation. In contrast, scheme 2 has two distinct inflection points at 0.66 m and 0.81 m, and the slope increases with speed in this range. When the vibration of vehicles traveling at speeds above 100 km/h, the vertical attenuation effect of geocell-reinforced aeolian sand is the most obvious.  
Figure 15 depicts the amplitude attenuation of primary frequency amplitude and equivalent amplitude at various structural layers. After aeolian sand is reinforced with geocells, the proportion of primary frequency amplitude attenuation increases dramatically, ranging from 0.52% to 2.26%. Geocells reinforce a large rise in the equivalent amplitude attenuation of aeolian sand. Expanding 11.66, 2.57, 2.83, 5.58, 7.32, and 9.73, respectively, between 20 to 120 km/h. It demonstrates that the reinforcement of the geocell on the aeolian sand accelerates the vibration energy dissipation by the aeolian sand. The reinforcement impact grows with the speed of the driving vehicle when the driving vehicle's speed exceeds 40 km/h [55].  
At all vehicle speeds, geocell-reinforced aeolian sand attenuates more main frequency amplitude than gravelly soils, with a maximum difference of 2.4%. At driving speeds of 20 km/h, 40 km/h, 60 km/h, 80 km/h, 100 km/h, and 120 km/h, the main frequency amplitude attenuation ratio is 3.89, 1.08, 2.38, 2.51, 3.75, and 2.37 times that of gravel type soil. The proportion of equivalent amplitude attenuation of geocell-reinforced aeolian sand from 20 km/h to 120 km/h is 0.94, 0.61, 1.15, 0.81, 1.83, and 2.39 times that of gravelly soils. Polypropylene resin geocells increase the aeolian sand's dynamic elastic modulus and damping. The aeolian sand's compression properties and deformation characteristics under  
Figure 14: Equivalent amplitude decay curve.  
traffic loads are changed by geocell. Moreover, geocells restrict lateral soil deformation and prevent the development of shear zones in the soil, increasing the soil's load-bearing capability and enhancing its vibration suppression performance [56; 57]. Thus, the vibration resistance of the geocell-reinforced aeolian sand layer exceeds that of the gravelly soil layer in most cases.  
In addition, as driving speed increases, the proportion of equivalent amplitude attenuation of geocell-reinforced wind-cumulus increases. Specifically, there is a substantial increase from 0.75% to 1.64% between 80 km/h and 100 km/h. The vibration response of the system increases sharply after approaching a critical driving speed was also concluded [58; 59].