###### Abstract  
The natural caving method, as a new technique in underground mining, has been promoted and applied in several countries worldwide. The destruction of the bottom rock mass structure directly impacts the structural stability of underground engineering, resulting in damage and collapse of underground tunnels. Therefore, based on the principles of explosion theory and field monitoring data, a scaled three-dimensional numerical simulation model of underground blasting was constructed using LS-DYNA19.0 software to investigate the attenuation patterns of underground blasting vibrations and their impact on nearby tunnels. The results show that the relative error range between the simulated blasting vibration velocities based on the FEM-SPH (Finite Element Method-Smoothed Particle Hydrodynamics) algorithm and the measured values is between 7.75% and 9.85%, validating the feasibility of this method. Significant fluctuations in blasting vibration velocities occur when the blast center increases to within a range of 10-20 m. As the blast center distance exceeds 25 m, the vibration velocities are increasingly influenced by the surrounding stress. Additionally, greater stress results in higher blasting vibration velocities and stress wave intensities. Fitting the blasting vibration velocities of various measurement points using the Sadovsky formula yields fitting correlation coefficients ranging between 0.92 and 0.97, enabling the prediction of on-site blasting vibration velocities based on research findings. Changes in propagation paths lead to localized fluctuations in the numerical values of stress waves. These research findings are crucial for a deeper understanding of underground blasting vibration patterns and for enhancing blasting safety. umerical modeling; blast vibration; FEM-SPH algorithm; explosion center distance; in situ 2024 14 10651. 10651. In investigating the influence of the distance from the blast source on the blast vibration velocity, early studies by [PERSON] and [PERSON] and many other scholars explored the effects of blast distance on blast vibration intensity and proposed a series of empirical prediction models for blast vibration intensity [6; 7; 8; 9]. [PERSON] et al. revised the empirical formulas for blast vibration velocity prediction used by previous researchers, taking the influence of charge size on the vibration velocity during explosions into account [10]. [PERSON] et al. considered the non-elastic attenuation of energy during the propagation of seismic waves in explosions, proposing that the peak velocity of explosion-induced vibration decays exponentially [11]. [PERSON] et al. proposed a new peak velocity prediction model for blast vibration in complex terrain environments, which improves the accuracy of the Sadovsky formula and enhances the prediction accuracy of peak blast vibration [12]. [PERSON] et al. proposed a fully orthogonal empirical modal decomposition method for blasting delay identification, which is capable of accurately identifying the peak value of the blasting vibration wave at the measurement point. [13]. In studies on the propagation path and medium properties of blast vibrations, [PERSON] et al. investigated the characteristics of blast vibration responses in the cross-section and axial directions of pilot tunnels through numerical simulation. Influenced by the propagation path, the vibration velocity in the unexcavated direction of the pilot tunnel is higher, while the attenuation rate in the direction of the excavated tunnel is faster [14]. [PERSON] et al. compared the attenuation characteristics of different waves and their respective influences on blast vibrations. The results indicate a close correlation between the vibration direction at each measurement point and the propagation path, location, and composition of the waves [15]. [PERSON] et al. obtained images of source functions acting on borehole walls through the numerical simulation of blast waves, with peak pressures matching the impact pressure between blast products and rocks [16].