A dynamic centrifugal model test was conducted for a homogeneous sandy slope under an impulsive ground motion to investigate the relationship between seismic response and slope deformation. Firstly, the deformation characteristics and dynamic responses of the slope were analyzed. Then, the main features associated with the response truncation effect were expounded. Subsequently, the Sliding block theory was introduced to explain the mechanism of the acceleration response truncation effect. At last, an approximate calculation method for the sliding mass dynamic response was developed, considering the influence of the truncation effect. The results show the variation pattern of response differs inside the slope and near the slope surface, and the dynamic amplification coefficients calculated by different methods also exhibit significant variations. The truncation of horizontal response acceleration results from the relative sliding in slope, and the truncated response fluctuates around a limited value related to the yield acceleration.

The highway network is densely distributed in the southeast coast of China. Highway subgrades passing through soft soil areas often produce large settlements, resulting in pavement cracking, bridgehead jumping, and other diseases. In order to study the effect of three trenchless treatment technologies of oblique jet grouting pile (JGP), lateral displacement limiting pile (LDLP), and load reducing pipe (LRP), centrifugal model tests were carried out under three treated conditions and without treatment. Based on the data of pore water pressure and settlement in the range of the half embankment model and outside the embankment, the settlement characteristics of highway soft soil foundation during the test simulation were studied, and the characteristics of different treatment methods were compared. The high level of pore water pressure corresponds to the rapid development of settlement. The average settlement during the existing operation period accounts for 96.7% of the total settlement of the simulation period, and the settlement does not converge. The methods can effectively inhibit the development of settlement, and each has its own characteristics: the LRP method does not involve foundation treatment, so its settlement characteristics are closest to that without treatment. The LDLP method can obviously limit the settlement within the embankment range and the pore water dissipation. The JGP method enhances the synergistic deformation ability of the embankment and significantly decreases the differential settlement.