Abstract The vibration induced by the transient unloading of in-situ stresses(ISTU) is an important part of the eventual excavating vibration during the tunnel blasting excavation. In order to reveal the energy distribution characteristics of vibration induced by ISTU and its influence on the energy distribution of eventual excavating vibration,the energy distribution characteristics of vibration induced by ISTU under different in-situ stress levels and blasting loads were studied with the method of power spectrum analysis. The results showed that the frequency-band energy distribution of vibration induced by ISTU and blasting load were basically identical,but the main frequency of vibration induced by ISTU was lower than that induced by blasting load. The vibration induced by transient unloading of in-situ stresses was an influential factor,and it increased the low frequency component of vibration energy. The increase of in-situ stress level raised the vibration amplitude induced by ISTU and did not affect the frequency-band energy distribution.
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