Dynamic Response Characteristics of Foundation of Mined-out Areas under High-speed Railway Load

To reveal the dynamic response characteristics of the foundation of mined-out areas (MOA) under the high-speed railway (HSR) load is important for predicting settlement and safety assessment of the foundation. Taking MOA of Dianshang under the Taiyuan-Jiaozuo HSR as the engineering background, the model experiments and numerical analysis were employed to reveal the dynamic response of both subgrade and the foundation of the HSR, as well as the attenuation law of the acceleration in the overlying strata of the MOA. Results show that within the full frequency range of the HSR load, the dynamic response of the foundation increases with the increase in load frequency. When the depth exceeds 6 m, the dynamic response of the foundation initially increases and subsequently decreases with the increase in load frequency. Contrasted with single- point loading, the superposition effect and moving effect of the HSR load will form a dynamic response superposition zone within 1-4 m below the subgrade, leading to a significant enhancement of the dynamic response of the foundation. Compared to HSR axle load, the driving speed of HSR has a greater impact on the acceleration of both the subgrade and foundation. The obtained conclusions provide a reference for the safety operation of the HSR crossing the MOA.