随着高速铁路网的快速推进，一些关键线路不可避免地穿越采空区场地，对高速铁路的建设和安全运维提出了更高的要求，研发相关试验系统是研究此类科学问题的重要手段。针对国内外缺乏相关试验系统的问题，研发了一套采空区场地高速铁路路基动力加载模型试验系统。建立了几何相似比为1∶100的二维采空区场地高速铁路路基模型，利用三级傅里叶级数拟合得到相似常数为100时，时速360 km/h对应的40 Hz高速铁路M波。同时实现了误差10%以内高铁荷载M波输出，验证了采空区场地高速铁路路基模型动力加载试验的可行性，并进行了100万次不间断的高速铁路M波循环加载。依据模型试验结果，阐述了主关键层下三角形离层空间的成因，讨论了不同加载阶段动荷载在采空区覆岩中的传递路径，分析了垮落断裂带与弯曲变形带在动荷载作用下的相互作用，揭示了高铁荷载下采空区地基活化机理。研究表明：覆岩活化空间具有从移动边界到垮落覆岩中心逐渐减少的分布规律，其中覆岩横向离层则具有从顶板至关键层逐渐增大的分布特征，以此揭示了主关键层下三角形离层空间的成因。因主关键层下三角形离层空间的隔离作用，加载初期动荷载传递需通过覆岩移动边界的拉伸区向下传递至垮落断裂带，并最先影响移动边界的砌体梁结构使其失稳活化。随着动荷载的施加，主关键层下离层空间逐渐闭合，动荷载传递路径逐渐向采空区中心移动，剩余活化沉降量持续向上传递，整体沉降趋于平缓。由于荷载传递路径的变化，垮落断裂带活化具有先快后慢，由终采线向采空区中部发展的特征。垮落断裂带活化进一步影响了主关键层以上覆岩受力形式和模型表面不均匀沉降，使弯曲变形带具有横向、竖向、倾斜3种裂隙形式及沿路基两侧的分布特征。

With the rapid advancement of the high-speed railway network, it is inevitable that some key lines will cross the mininggoaf site. This poses higher requirements for the construction, safe operation, and maintenance of high-speed railways. To address these scientific issues, the development of related test systems becomes an important approach for a comprehensive study. However, there is a lack of relevant test systems both domestically and internationally. To fill this gap, a dynamic loading model test system for high-speed railway subgrade in mininggoaf sites has been developed. This system involves the creation of a two-dimensional high-speed railway subgrade model with a geometric similarity ratio of 1∶100. By using a three-stage Fourier series fitting, the 40 Hz high-speed railway M-wave corresponding to a speed of 360 km/h is obtained when the similarity constant is 100. Additionally, the system allows for the realization of the M-wave output of high-speed load within a 10% error, thereby verifying the feasibility of dynamic loading tests for the high-speed railway subgrade models in mining goaf areas. The system also enables the performance of 1 million uninterrupted M-wave cyclic loadings for high-speed railways. This study examines the causes of the triangular separation space under the main key stratum and discusses the transmission path of dynamic load in the overburden rock of the goaf at different loading stages. It analyzes the interaction between the caving fault zone and the bending deformation zone under dynamic load, and reveals the activation mechanism of the foundation in the goafunder a high-speed rail load. The research findings indicate that the activation space of the overburden rock gradually decreases from the moving boundary to the center of the collapsed overburden rock, and the horizontal separation of the overburden rock gradually increases from the roof to the key stratum, thus explaining the cause of the triangular separation space under the main key stratum. The triangle abscission layer space acts as an isolation barrier, requiring the transfer of dynamic load downward to the caving fault zone through the tensile zone of the moving boundary of the overlying rock during the initial stage of loading. The masonry beam structure, which first affects the moving boundary, becomes unstable and activated. With the application of dynamic load, the separation space under the main key stratum gradually closes, causing the dynamic load transfer path to shift towards the center of the goaf. The residual activated settlement continues to transfer upward, resulting in an overall settlement that tends to be more gentle. The change in load transfer path leads to the activation of the caving fracture zone, which initially occurs rapidly and then slows down, extending from the stop line to the middle of the goaf. The activation of the collapse fault zone further impacts the stress distribution in the overlying rock above the main key layer and causes an uneven settlement on the model surface. This results in the formation of three types of cracks (transverse, vertical, and inclined) in the bending deformation zone, which are distributed along both sides of subgrade.