Attenuation of blasting vibration in a railway tunnel

Abstract

In order to deeply explore the propagation and attenuation law of column charge blasting stress waves or seismic waves, and to improve the prediction model of the blasting peak vibration velocity, a theoretical study on the blasting peak vibration velocity was carried out. First of all, based on the Heelan short-column charge theory, the concept of the equivalent radius of action was introduced, and the attenuation equation for the blasting peak vibration velocity under the action of the internal instantaneous excitation load was obtained. Then, the concepts of the equivalent action radius and equivalent blasting load were applied to the theoretical derivation of the blasting peak vibration velocity. The attenuation laws of the blast-induced vibration in cutting hole sections and non-cutting hole sections were studied, respectively. Finally, based on the dimensional harmony theorem, the reliability and universality of the attenuation model were verified. Combined with an example of tunnel blasting project, the attenuation laws of the blasting peak vibration velocities corresponding to different segments of detonators and different types of blast holes were studied. The results show that the improved formula can well fit the peak velocities of the above two types of blasting vibrations, which can accurately reflect the transmission law of the tunnel blasting vibration. In addition, the expressions of the charge form of the improved formula under the conditions of spherical charge and columnar charge were discussed, and the prediction effects of various fitting models were compared. The comparison results show that using the equivalent radius of action as a fitting reference variable can comprehensively consider the influence of different detonator positions and different blast hole types on the blasting vibration attenuation law. The reference variables of the statistical data show that the fitting effect obtained by the improved formula is the best, which can provide a reference for similar research of tunnel blasting vibration.