Abstract: The propagation characteristics of seismic waves in soft soil are crucial for enhancing the seismic resilience of buildings. By analyzing the attenuation properties of dynamic peak acceleration (PGA) through centrifugal vibration table tests, we aim to enhance our understanding of the impact of soil properties on seismic wave propagation. To accomplish this, we adjust the obtained soil samples to moisture contents of 35%, 45%, and 55% and perform conventional physical tests. Subsequently, the cluster morphology and tangential stiffness of particle bonding within the model will be determined by macro-micro parameters, including friction factor, Poisson ratio, and other critical factors like the damping ratio. Additionally, both the mass damping β_n  and the stiffness damping k_n  will be meticulously examined as they regulate particle motion and collisions. According to the results of the conventional physical test of the different moisture contents, the effect of soft soil on the decay effect of PGA under different moisture content conditions are studied. The research results show that under different ground motion conditions, the peak acceleration in soft and hard layered soil at a depth of 30 m presents a change law of slow attenuation, sharp attenuation and then rebound rise. With the increase of water content, the attenuation ratio of peak acceleration in the depth of 30 m to 8 m increases in the range of 2.33 to 2.70. The corresponding magnification of 8−0 m depth strata decreases in the range of 1.60−1.23. The period of the response spectrum 0.2−1.1 seconds corresponds to the middle and low frequency range, and the acceleration value shows an increasing trend; the higher frequency range corresponds to the period 1.1−2.0 seconds, and the acceleration value generally shows a decreasing trend, which is consistent with the high-frequency attenuation effect. Through comparison and verification of numerical simulation and theoretical analysis, the law of ground motion propagation and amplification near the surface under different water contents is preliminatively verified, which provides a theoretical basis for assessing earthquake disaster risk and improving earthquake protection.

Key words: seismic waves, amplification effects, DEM, PGA, moisture content