Abstract: To address the dual challenges of environmental risks caused by the storage of mine tail ⁃ ings and the instability of subsidence areas，and in response to the key influence of the control of the ratio of sand to cement on the dynamic mechanical properties and engineering applicability of the filling body，a Separated Hopkinson Pressure Bar（SHPB）dynamic impact test system was adopted to compare and ana ⁃ lyze the strength evolution laws and energy dissipation mechanisms of filling bodies with a ratio of 1 ∶4，1 ∶6， and 1 ∶8 under high strain rate loads.The research results show that at the same strain rate，increasing the sand-cement ratio increases the dynamic compressive strength by 13.5%to 107.4%，and reduces the impact damage degree.The analysis of impact failure morphology indicates that the high sand-cement ratio（1∶4） specimens exhibit brittle crushing failure，while the low sand-cement ratio（1 ∶8）specimens show axial splitting-shear composite failure.The study on energy dissipation mechanism reveals that under the same incident energy conditions，the energy absorption rate of the 1 ∶8 sand-cement ratio specimens is 43.75% higher than that of the 1 ∶4 specimens，verifying the ductile characteristic of the high sand-cement ratio filling body in dissipating impact energy through plastic deformation.Engineering applications demonstrate that through collaborative treatment of subsidence areas，this technology can reduce the accumulation vol⁃ ume of tailings by 85%，and the strength of the filling body after 28 d can reach 2.1 MPa.The research confirms that optimizing the sand-cement ratio to 1 ∶6 and 1 ∶8 can not only meet the dynamic bearing re ⁃ quirements but also achieve energy dissipation balance，providing theoretical support for the construction of a tailings-free mining mode.

Key words: cemented filling bodies, control of sand-cement ratio, compressive strength