# Seismic Wave Amplification Characteristics in Slope Sections of Various Inclined Model Grounds
## 5 Conclusions  
This study examined the seismic amplification characteristics in slope sections using the model grounds with single-layer slopes (\(D_{r}\) = 75% (Case 1), \(D_{r}\) = 85% (Case 2)) and multi-layer flat (Case 3) and slope (Case 4) model grounds on a 1 g shaking table. The peak ground acceleration (PGA) in the slope and vertical sections was compared, and the areas with significant impact on PGA were analyzed using contour plots. The reliability of the experimental results obtained from the model grounds on the 1 g shaking table was validated by comparing them with numerical simulation results. The findings of the study are as follows:  
1. The analysis of peak ground acceleration (PGA) results showed that the acceleration amplification from the lower to the middle and upper parts of the slope was greater in the sloped model grounds compared to the flat model ground. The least amplification occurred in the flat ground of Case 3, while greater amplification was observed in the order of Case 1, Case 4, and Case 2.
2. The contour plots of PGA trends revealed varying patterns of amplification at different points. It was found that, on average, approximately 60% of the PGA impact occurred at the topmost part of the slope, with specific amplifications of about 31.75% at the upper slope and 27.85% at the lower slope compared to the input motion. These re  
Figure 9: Comparison of spectral acceleration results between numerical analysis and 1 g shaking table tests: (**a**) Case 1 (\(D_{r}\) = 75%) ground model, (**b**) Case 2 (\(D_{r}\) = 85%) ground model, (**c**) Case 3 (2 layer flat) ground model, (**d**) Case 4 (2 layer slope) ground model.  
sults suggest that the influence of PGA varies across different points on the slope, and such variations should be carefully considered when designing seismic reinforcement. In the multi-layered model ground, different amplification patterns were observed at the layer transition points, indicating that the stratification of the ground significantly affects seismic wave amplification. This finding underscores the importance of accurately understanding the layered structure during the design process.
3. When comparing the experimental results with the numerical analysis results through Spectrum Acceleration (SA), differences of 3.22%, 3.39%, 2.56%, and 2.24% were observed for each case. Overall, there was approximately a 3% difference. The good agreement between the numerical analysis and the 1 g shaking table experiment results suggests that the experiments using the shaking table are valid.
4. This study identified differences in seismic wave amplification due to variations in relative density and layered soils. It also observed varying PGA values at different points. These findings suggest that in future ground design, especially for various geometric configurations, it is crucial to consider the effects of layered soil profiles, differences in relative density, and the diverse PGA values at different points. Based on the contour plot analysis, it is considered that approximately 60% of the PGA impact should be considered in seismic design, particularly at the topmost part of the slope.  
Writing--original draft preparation, S.J.; validation, M.M.; review, editing and supervision, D.K. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Research Foundation of Korea (NRF), NRF-2021R11A3044804.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflict of interest.