# Energy Generation and Attenuation of Blast-Induced Seismic Waves under In Situ Stress Conditions
## 1 Introduction
Their numerical results show that the vibration frequency of blasting seismic waves becomes higher as the in situ stress exerted on the rock mass increases. Focusing on structural discontinuities in actual rock masses, [PERSON] and [PERSON] [26], [PERSON] et al. [27], and [PERSON] et al. [28] investigated the seismic wave propagation in a stressed rock mass with a single joint by using theoretical methods. It is found that the seismic wave attenuation across the joint is dependent not only on the stress level and lateral coefficient but also on the incident wave direction. [PERSON] et al. [29] and [PERSON] et al. [30] carried out numerical studies on stress wave propagation in stressed rock masses with multiple joints. They find that the stress wave attenuation across the joints also relies on the number and spacing of the joints, as well as the amplitude and frequency of the incident waves. The wave propagation in the jointed rock mass is susceptible to the variation of joints when the preloaded stress is lower. However, with an increase in the initial stress, the influences of the joint variation on the stress wave propagation gradually diminish. [PERSON] et al. [31] also carried out related experimental research. The results indicate that the transmission of incident waves across the joints first increases and then decreases as the initial stress increases from zero. In addition, [PERSON] et al. [32] experimentally investigated the blast-induced dynamic strain field in stressed sandstone specimens. They observe that the increase rate of the blasting strain is inhibited by the compressive strain due to the initial stress. The above studies show that during blasting in deep or stressed rock masses, the generation and propagation of blasting seismic waves are affected by in situ stress. However, the current studies in this regard are mainly concerned with the seismic wave amplitude and its attenuation with distance or across joints. However, there are few pieces of research reported on the initial seismic energy generated in deep rock blasting and its attenuation under different in situ stress conditions, especially for multiple-hole blasting. In fact, this is an important issue because it involves energy distribution and energy efficiency of deep rock blasting. In this study, the seismic energy generated in deep rock blasting and its attenuation with distance is theoretically analyzed first to reveal the effect mechanisms of in situ stress on blasting seismic energy. Numerical simulations of multiple-hole blasting for a circular excavation under hydrostatic and non-hydrostatic in situ stresses are then conducted with the coupled smoothed particle hydrodynamics (SPH) and finite element method (FEM). According to the simulated results, the effects of in situ stress levels and anisotropy on the initial blasting seismic energy are investigated. Furthermore, the seismic energy attenuations under varied in situ stress conditions are analyzed. Finally, a case study in which the blasting vibration monitoring was carried out in the rock masses with different in situ stress levels is presented to verify the theoretical and numerical results.