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When the line project passes through a large area of aeolian sand, cement mixing piles are often used to reinforce the subgrade, which can effectively improve the bearing capacity of the subgrade, but its anti-liquefaction effect is worthy of in-depth evaluation. Intermittent earthquakes cause more than one liquefaction of aeolian sand subgrade, so it is worth further research on the re-liquefaction characteristics of cement mixing piles in treatment of aeolian sand subgrade. In this paper, a real-time comparative test (pile reinforced area and unreinforced area) is carried out through a shaking table, and the liquefaction and re-liquefaction characteristics of the reinforced subgrade are mainly explored. The experimental model will produce the following results under 0.4g EL Centro wave excitation:(1) The pore pressure will have multiple peaks, causing the surface of the model to float or sink. The phenomenon will be weakened by experiencing multiple earthquakes of the same level or using pile reinforcement;(2) The deeper the burial depth, the longer the time for the pore pressure to reach the maximum peak value. After multiple vibrations, the corresponding time of the shallow layer in the unreinforced area and the deep layer in the reinforced area doubles;(3) The cement mixing pile can improve the liquefaction and re-liquefaction resistance of aeolian sand foundation, and the effect is best in the shallow foundation, with an increase of more than 30%, and the deeper the burial depth, the lower the effect;(4) After the subgrade has experienced a strong earthquake, its resistance to liquefaction will be improved, but the acceleration response during the next earthquake will increase significantly.

The relationship between slope and prevention structures under the action of rainfall is complicated. In this paper, a series of model tests were carried out to study the coevolution mechanism of slope and prevention structures under rainfall. It was found that the prestressed grouting steel anchor tube frame beam composite structure has a good reinforcement and protective effect on the slope. Specifically, less damage degree is observed for a slope with prestressed grouting steel anchor tube frame beam, while the slope of without prestressed grouting steel anchor tube frame beam suffers from severe deformation. Under the effect of rainfall, the evolution process of slope and prevention structure cooperative deformation can be divided into three stages: creep stage, extrusion stage, and acceleration stage. The antisliding force provided by the prevention structure is positively correlated with the slope deformation. Moreover, as an initiating factor for changes in various monitoring parameters, rainfall plays a dominant role in the variation of earth pressure reinforcement by steel anchor tube.

With the vigorous development of railway and highway construction, tunnel construction often follows the mountains and rivers, crossing high-intensity landslide areas, and potential earthquakes triggering damage in areas including tunnel landslides have become a hot issue today. Based on this, this paper performs a shaker test on the tunnel-containing landslide body, inputs horizontal seismic waves, and tests the acceleration response data of different bits in the landslide body. By analyzing the temporal and frequency domain transformations of the acceleration response at different positions in the slope body combined with the deformation characteristics of the slope, and then analyzing the seismic response of the slope under the action of the front and back seismic sequences, the results show that (1) the existence of the tunnel has the effect of energy dissipation and vibration reduction, making the energy input at T8, and the measuring point on the upper part of the tunnel at the lowest. (2) When the seismic wave is transmitted, it will cause reflection around the tunnel, forming complex seismic wave field, resulting in the irregular distribution of acceleration amplification coefficient. (3) There is a high correlation between seismic responses of different levels. When the acceleration response of the preseismic response to the landslide-containing tunnel is not considered, the acceleration response of the postseismic response to the slope and the structure will be lower than the real value. (4) The sequence of failure at different locations of landslide mass containing tunnel is found through marginal spectrum analysis. It is concluded that the failure mode of landslide mass with tunnel is extrusion and sliding out of the middle slope. The research results can provide some reference for the reinforcement design of landslide with tunnel in high-intensity area.

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